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Frequently Asked Questions

The purpose of this section is to highlight some of our more popular questions about the Baxter, Sawyer, and Intera and to point you in the direction of the solutions to the associated conundrums.


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Maintenance

Q: Is there any preventative maintenance that should be performed on my Baxter robot?

A: See the Preventative Maintenance page for more information, but note that Baxter contains DC brushless motors and sealed gear boxes in each joint and there is very little preventive maintenance required.

Q: One arm on Baxter is "pulling" when in Zero-G mode... What can I do about this?

A: This probably means that your Baxter's arms need to be calibrated! See the page on Calibration for details.

Q: A spring on an arm of Baxter is making a squeaking or groaning noise. How do I go about fixing this?

A: Apply some grease to the gravitational compensation spring. How to Grease the Gravitational Springs is a guide on doing this.

Q: The foam on the fan cover appears to be very dusty? How do I clean it?

A: It's good practice to clean the filters on the fan covers to ensure clean air enters Baxter's torso. Click here for a guide on doing this.

Hardware

Q: What kind of grippers work with the Baxter Robot?

A: Rethink Robotics sells two types of grippers to be used with Baxter. The Electric Gripper and the Vacuum Gripper. Intera 3.2 introduced the ability to recognize custom end of arm tooling on Baxter. For more information about custom end of arm tooling that customers have been successful in using with Baxter, contact Rethink Robotics Support for more information.

Q: How do I use my custom (non-Rethink) pneumatic gripper on Baxter?

A: In some cases, pneumatic grippers designed to use an M8 NPN sensor may be able to be recognized by the Intera software as a parallel gripper and utilize Pick and Place functionality. These can be connected by interfacing with the Rethink pneumatic gripper cable (sold separately). See Pneumatic Parallel Grippers. Other pneumatically actuated endeffectors may be installed on the robot and actuated using external I/O. See Custom Grippers. For more information on using custom end of arm tooling or pneumatic grippers, contact Rethink Robotics Support.

Q: Where can I find general hardware specifications for my Baxter?

A: See detailed specifications here. Datasheet: Baxter Datasheet

Q: How do I shutdown the robot?

A: Follow the instructions to shut down the robot.

Q: What are the required dimensions for the Baxter workspace?

A: See the Workspace Guidelines page for more information.

Q: Can I run Baxter off a battery pack or mobile power source?

A: No.

Q: How often does Baxter need to be calibrated?

A: We recommend calibrating the arms at least once a month. See Calibration for more detailed information

Training

Q: Baxter has a confused face. What does this mean?

A: This feedback typically means that the robot has run out of parts to pick, however it may be indicative of a different issue. Please visit the Confusion section.

Q: How do I configure multiple place locations from one pick?

A: In the simplest example, a subtask with one pick and two place locations can be created to branch. Each place location can have a separate ready signal when triggered will command the arm to that particular location. See the Pass/Fail Tasks example for help in setting this up.

Q: How do I convince my boss that Baxter is safe without guarding?

A: The robot was built to be safe to work around but it's highly recommended that each company perform their own safety assessment before deploying Baxter at a particular application. Baxter is part of a system that includes the robot, end effectors, parts, and other equipment and the safety assessment should be performed in the context of the system. Learn more at the Safety and Compliance page.

Q: Who do I contact if I have an issue?

A: If you have questions or issues with Baxter, please contact Support at 866-704-7400

Q: Can I order replacement parts for grippers?

A: Yes! Please contact your regional distributor or Rethink Sales to place an order.

Q: If Baxter breaks, can I do my own repairs?

A: Please contact Rethink Support before attempting any repair. The robot may be covered under warranty, which would make you eligible for a Rethink Field Engineer to come on site and repair Baxter.

Q: How long is my warranty?

A: Baxter comes with a standard 1 year warranty. There are an additional 2 years of warranty that are available for purchase.

Q: Can the arms do two tasks independently?

A: Yes, the arms can be trained to run completely separate motions. Technically, the arms will both be running the same task but do not necessarily need to be working on the same parts or performing the same operations.

Q: Can I switch tasks with a signal?

A: This is not currently supported in the software, however you may be able to accomplish the same goal by building each routine into one task, and using signals to command which sub-task is run and when.

Q: Why do the arms fall when I hit the E-stop?

A: Hitting the E-stop cuts off all power to the motors in the arms. Therefore the arms will fall slowly to a safe position. It is recommended that an Error Output signal is used on a production task to alert other machinery that the robot has had an Emergency-Stop.

Q: To train an action group, can I give Baxter the number of rows and columns and let it calculate the locations?

A: This is not currently supported in the 3.3 software version.

Q: Can I train a “safe zone” around my fixtures so that Baxter does not bump into them?

A: No. But every action has a path into and out of that action. The robot will automatically generate paths during the task training, however the paths can be re-trained and modified to ensure the arms do not come in contact with any fixture in the workspace. See Paths for more information.

Q: How often does Baxter need to be calibrated and why?

A: We recommend calibrating the arms at least once a month to ensure the best arm performance and accuracy. See Calibration for information about calibrating the arms.

Q: Why is my calibration failing?

A: make sure that end of arm tooling has been removed from the robot before calibrating, the robot is level, and the arms are free from obstruction. See Calibration for troubleshooting tips.

Q: Why is the current pose invalid? It is within the work area on the task map.

A: Be careful that none of the 7 joints on the robot's arm are at or near a hard limit. If a joint is near a hard limit, the robot may not allow you to create a pick, place, or hold in this joint configuration. You can determine if the arm is near a hard stop or close to the screen if the arm icon on the user interface has been grayed out.

Q: Does Baxter slow down when the sonar detects someone?

A: The sonar is not currently used in the 3.3 software, and is a placeholder for future functionality.

Q: Can I use vision to inspect the part?

A: The cameras in the robot are not currently available to be used for inspection. The cameras are used for the Robot Positioning System. Intera 3.2 allows you to create task using only hold actions and you can add external camera to do part inspection.

Q: Why can’t I train a task that consists of all holds?

A: Hold only tasks are available in Intera 3.2. If your robot is an older version of software, please contact Rethink Robotics support for the latest software upgrade.

Q: How long is the count pulse?

A: The output signals from Baxter are approximately 0.5 seconds long. You can verify the output is being sent from Baxter to your external devices by connecting to Task Editor.

Q: Can Baxter pick up something with both arms?

A: No, Baxter cannot pick up one object with both arms.

Q: Why are approach/retract and done grayed out in the advanced settings dialog?

A: This may mean that the approach and retract locations may be too far for the arm to reach. Be mindful that although an arm may be able to reach an Action location, it does not necessarily mean the approach and retract locations are valid. See Workspace Guidelines for more information.

Q: Does Baxter’s torso rotate?

A: Baxter's torso does not rotate, however both arms together have 360 degree reach around the work-space.

Q: Can I set the number of pick attempts?

A: Yes. Baxter's pick attempt value is defaulted to 2. After 2 missed picks, the robot will become confused. If more or less pick attempts are needed, you can change the default setting in the more options section of the Task Order Screen.

Signals

Q: How do I configure a PLC to communicate with Baxter?

A: Baxter communicates with the outside world through the Ethernet port on the back of the robot's torso via MODBUS TCP/IP. Your PLC must be either MODBUS enabled or digitally connected to a MODBUS device in order to successfully communicate, send, and receive signals to and from the robot. For information on connecting external devices to Baxter, see the Configure Modbus sections.

Q: How long will a Done signal stay true after completing a Task, Subtask, Action?

A: In Intera 3.2 and earlier, the Done signal remains true until the count on the element is reset. In Intera 3.3, Done signals will remain true for the pulse duration set on that particular done signal. In general, the Done signal will remain true for no less than .5 seconds and can be monitored by using Monitor Mode.

Q: Why doesn't my Action run the second time through even though the Ready signal has always been true?

A: Check the count, which is only reset on the rising edge of Ready. Therefore, if you have a count of 1 and you leave Ready true, the Action will only happen once and the count will never be reset. If you’re using Ready to control a Pick, set the count to infinity. If you’re using Ready to control a Place and are using multiple subtasks, you can either set the count to infinity and use the Skip signal to move on to the next subtask or make sure that you cycle Ready false to true to reset the count.

Q: How do I use signalling and an external PLC to run Action Sequences out of order?

A: See here for more information on signals.

Q: If I invert an output signal (e.g. Done) and have not started the task, what will the output be and when does it become inverted?

A: Inversion takes place as soon as the modification is saved in the task and the changes have time to propagate throughout the system, typically a second or so.

Q: If two input signals become true at the same time (e.g. Pick Ready and Subtask Skip), can I predict what will happen? Is there a way to understand what has a higher probability of getting chosen?

A: Relying on the robot’s behavior in this case is fundamentally unreliable system design. This is a classic synchronization problem and there is fundamentally no way to predict which signal will take priority. Whichever one Intera happens to notice first will take effect. Note that even in a procedural language, where you might be checking one signal then the other in a loop in order to decide what to do next, if they change at literally the same time you can’t predict which one will be noticed first. In situations where two signals might change at nearly the same time and predictable behavior is defined and required, we highly recommend that you use a PLC and logic that creates a window in which both signals are examined and an unambiguous decision is made, which is then communicated to and synchronized with Intera by asserting only one signal representing the required action

Q: Why is Baxter confused when I try to run my imported tasks?

A: When importing tasks with signals, make sure the device names associated with each signal are renamed to the corresponding device for the destination robot.

Q: How long will a Done signal stay true after completing a Task, Subtask, Action?

A: In general, the Done signal remains true until the count on the element is reset. When using automatic reset, i.e., the Ready signal isn’t being used, Action counts are reset when their containing Subtask ends, whereas Subtask counts are reset when the Task completes. Due to the automatic resetting (e.g., in a Subtask with only one Place Action, the Subtask will end when the count is satisfied and then immediately reset the count) Done signals may only stay true for a short period of time, but in any case no less than 0.5 seconds.

Q: Why doesn’t my Action run the second time through even though the Ready signal has always been true?

A: Check the count, which are only reset on the rising edge of Ready. Therefore, if you have a count of 1 and you leave Ready true, the Action will only happen once and the count will never be reset. If you’re using Ready to control a Pick, set the count to infinity. If you’re using Ready to control a Place and are using multiple subtasks, you can either set the count to infinity and use the Do Subtask signal to move on to the next subtask or make sure that you cycle Ready false to true to reset the count.

Q: How do I use signalling and an external PLC to run Action Sequences out of order?

A: There are two main approaches to using signalling to run sequences out of order using an external PLC:
  1. Put multiple Action Sequences into single Subtask using the combine operation on the Task Order screen. Use Ready signals on the Picks to choose which Action Sequence to run.
    1. Counts should be set to infinity for all Picks and Places, since the single subtask never ends and the sequence is being controlled externally.
    2. The Ready signal for a Pick must be held true until the action completes. A way to reliably synchronize is to monitor the Increment Count signal and use that to clear Ready. An alternative approach would be to use the Increment Count on the corresponding Place, which would allow the Pick to repeat if the part was dropped. Which approach is better is highly application dependant.
  2. Put each Action Sequence into its own Subtask and use the Subtask Do Subtask signal to choose which Subtask to run.
    1. All Subtasks should have their own Do Subtask signal connected. In the idle case, all of the Do Subtask signals should be true.
    2. To run a particular Subtask, the PLC should set that Subtask’s Do Subtask signal to false. To operate reliably, the signal should remain false until the PLC receives a positive acknowledgement that the Subtask has started. This could be from the Start signal of the first Action, for example.
    3. In order to ensure that the Subtask doesn’t start again immediately upon completing the Action Sequence, Do Subtask should be cleared immediately upon receiving the indication that the sequence has started. Since Do Subtask is only looked at when no Action Sequence is running, this will allow the current sequence to complete and not restart.
    4. Do not use the Subtask Ready signal.

Q: In the case of a HOLD -> PICK -> PLACE, why won't the robot go back to the first HOLD when PICK READY is not enabled?

A: Action Sequences are defined to not start unless there is an available Pick. This is to prevent the robot from getting stuck in a sequence when a better choice might come along. For example, a Do Subtask signal might want to end the Subtask, but that can’t happen in the middle of an Action Sequence.

Q: If two input signals become true at the same time (e.g. Pick Ready and Subtask Do Subtask), can I predict what will happen? Is there a way to understand what has a higher probability of getting chosen?

A: Relying on the robot’s behavior in this case is fundamentally unreliable system design. This is a classic synchronization problem and there is fundamentally no way to predict which signal will take priority. Whichever one Intera happens to notice first will take effect. Note that even in a procedural language, where you might be checking one signal then the other in a loop in order to decide what to do next, if they change at literally the same time you can’t predict which one will be noticed first.

Q: If I want to use a signal in order to look for an absent space on a conveyor, how would I do that?

A: You could attach a Part Presence sensor to the robot and a Ready signal to the Place location. All you need to do is invert the signal so that instead of acting as a parts presence sensor, it actually works as a parts absence sensor.

Q: Why can the Error In signal not be assigned to a subtask?

A: An Error in signal will stop the robot's current operation. Since the task will need to be restarted after the signal is triggered, the signal can only be assigned at the task level.

Q: Can an Error In signal be used as a safety stop?

A: See the page on Safety and Compliance for more information.

Q: Will any counts in my task be reset when a Pause signal is used?

A: No, the pause signal does not reset any of the procedures currently running in the task. When the Pause signal is removed, all task elements will pick up exactly where the were when the signal was triggered.

Q: Why can I not assign a Pause signal to a subtask?

A: The Pause signal is designed to temporarily stop all robot actions. Stopping only one subtask would allow other task elements to continue to run.

Q: When I use a Skip signal on a Hold, does the arm still move through the Hold location in the Baxter workspace?

A: Yes, the Skip signal will work slightly differently on a Hold compared to on a Sub-task. When it is applied to a Hold, the arm will still move to the Hold point, but will not wait for the given Hold time. When the Skip is on a sub-task, all actions in the sub-task will be disregarded until the signal goes low.

Q: I have the skip signal tied to a sub-task and when my external devices sends the signal, the robot doesn't skip the sub-task. What am I doing wrong?

A: Because the robot is only looking for a sub-tasks's Skip signal for a brief moment the very end of the previous sub-task, you need to make sure that the incoming signal is held True (latched) for the time that you need the robot to not perform that particular sub-task.

Q: What is the difference between using an inverted Skip Signal and using a Do Subtask Signal?

A: These two signals are similar in that they directly impact if a subtask will be performed or not. Inverting the Skip signal will act similarly to the Do Subtask. However the Skip signal can also be applied to a Hold action.

Q: Why is the robot showing confusion when I use the reset in signal?

A: Make sure that when the reset is applied, the gripper is not holding anything. If the gripper has a part in hand, and the task is reset, the robot will become confused.

Q: What is the difference between a Reset signal and a Reset Count signal?

A: The Reset signal can only be applied at the task level and is used to reset every element of a task while the Reset Count signal can be assigned to different task elements (except Holds) and will only Reset the count of the specified element.

Q: Why can the Reset Count signal not be assigned to a Hold?

A: Holds cannot have counts, so the Reset Count signal does not apply.

Q: Can the Done signal be applied to a task element that does not have an associated Count?

A: Yes. While the Done signal will trigger the count of a task element has completed, it will also trigger at first completion of the task element if there is no associated count.

Q: In what scenario would I use a Count signal over a Done signal?

A: A Done signal will only trigger when the count of a task element is full. A Count signal will be used when you want to send an output at each increment of the Count and not only when it is full.

Q: How is an Error Out signal different from a Confusion signal?

A: An Error Out signal is used for more critical errors with the robot than the confusion signal. The Confusion signal typically means that an object is missing or something is not trained properly while an Error means that there is a more serious failure.

Q: What can cause the robot to enter a state of confusion?

A: See the Confusion page for more information.

Q: Why can I not assign an Action Started signal to a task?

A: There should be no need to assign this signal to a task since the start of a task is never triggered internally, so there would be no need to send out a pulse notification that this has begun.

Q: When is the Action Ended signal triggered if I have a count assigned to a specific action?

A: The Action Ended signal is trigger when the action has completed and the count is full.

Q: Why would I need to send Reset Out signal when I manually reset the task running on the robot?

A: The Reset Out signal would be used to trigger any associated devices so that each device does not need to be manually reset.

Q: When is it beneficial to use an Active signal over a Start signal?

A: The Active should be used when a level signal is required for the duration of a Hold action. The start signal will only send a pulse when the robot arrives at the approach point for an action while the Active signal will remain trigger for the entirety of the action.

Specifications

Q: What make the robot safe?

A: See our page on Safety and Compliance for more information.

Q: What is Baxter’s maximum grip force?

A: The Electrical Parallel Grippers maximum grip force (torque) is 10 lb / 4.4 kg

Q: What is Baxter’s accuracy?

A: Baxter's repeat-ability in space is +/- 2.5mm, however by leveraging the compliance of the robot's arm and using fixturing, one can achieve much tighter tolerances. Please see this video for an example of using compliance to gain tight tolerances.

Q: How many Inputs and Outputs can Baxter handle?

A: Baxter can handle upwards of 99 Inputs and Outputs by using a MODBUS Remote Terminal Unit or PLC. There are an additional 1 in and 1 out if you use the DB15 port.

Q: What is Baxter's payload?

A: Each arm has a payload of 5 lbs. This includes the weight of the gripper. Attempting to lift more weight may result in a hardware failure.

System

Q: Where is the robot's serial number located?

A: The serial number can be found on the back of the robot next to the power button. For more information, see Serial Number Information.

Q: How do I enter the Field Service Menu (FSM)?

A: See these detailed instructions on how to access the FSM.

Q: How do I set a Static IP address?

A: To set a static IP for Baxter, you'll have to access the Field Service Menu.

Q: What is Baxter's IP Rating?

A: Baxter is rated IP50. See Baxter Datasheet for Baxter's data sheet.

Maintenance

Q: Is there any preventative maintenance that should be performed on my Sawyer robot?

A: See the Preventative Maintenance page for more information, but note that Sawyer contains DC brushless motors and sealed gear boxes in each joint and there is very little preventive maintenance required.


Q: The foam on the fan cover appears to be very dusty? How do I clean it?

A: It's good practice to clean the filters on the fan covers to ensure clean air enters Sawyer's Control Box. See Cleaning Sawyer's Air Filter for a guide on doing this.

Hardware

Q: What kind of grippers work with the Sawyer Robot?

A: Rethink Robotics sells two types of grippers to be used with Sawyer. The Electric Gripper and the Vacuum Gripper. For more information about custom end of arm tooling that customers have been successful in using with Sawyer, contact Rethink Robotics Support for more information.

Q: How do I use my custom (non-Rethink) pneumatic gripper on Sawyer?

A: In some cases, pneumatic grippers designed to use an M8 NPN sensor may be able to be recognized by the Intera software as a parallel gripper and utilize Pick and Place functionality. These can be connected by interfacing with the Rethink pneumatic gripper cable (sold separately). See Pneumatic Parallel Grippers. Other pneumatically actuated endeffectors may be installed on the robot and actuated using external I/O. See Custom Grippers. For more information on using custom end of arm tooling or pneumatic grippers, contact Rethink Robotics Support.

Q: Where can I find general hardware specifications for my Sawyer?

A: Datasheets available here:

Sawyer Data Sheet

Sawyer Tech Specs

Q: How do I shutdown the robot?

A: Follow the instructions to shut down the robot.

Q: What are the required dimensions for the Sawyer workspace?

A: See the [here] page for more information.

Q: Can I run Sawyer off a battery pack or mobile power source?

A: No.

Training

Q: Sawyer has a confused face. What does this mean?

A: This feedback typically means that the robot has run out of parts to pick, however it may be indicative of a different issue. Please visit the Confusion section.

Q: How do I configure multiple place locations from one pick?

A: In the simplest example, a subtask with one pick and two place locations can be created to branch. Each place location can have a separate ready signal when triggered will command the arm to that particular location. See the Pass/Fail Tasks example for help in setting this up.

Q: How do I convince my boss that Sawyer is safe without guarding?

A: The robot was built to be safe to work around but it's highly recommended that each company perform their own safety assessment before deploying Sawyer at a particular application. Sawyer is part of a system that includes the robot, end effectors, parts, and other equipment and the safety assessment should be performed in the context of the system. Learn more at the Safety and Compliance page.

Q: Who do I contact if I have an issue?

A: If you have questions or issues with Support, please contact Support at 866-704-7400

Q: Can I order replacement parts for grippers?

A: Yes! Please contact your regional distributor or Rethink Sales to place an order.

Q: If Sawyer breaks, can I do my own repairs?

A: Please contact Rethink Support before attempting any repair. The robot may be covered under warranty, which would make you eligible for a Rethink Field Engineer to come on site and repair Sawyer.

Q: How long is my warranty?

A: Sawyer comes with a standard 1 year warranty. There are an additional 2 years of warranty that are available for purchase.

Q: Can the arms do two tasks independently?

A: Yes, the arms can be trained to run completely separate motions. Technically, the arms will both be running the same task but do not necessarily need to be working on the same parts or performing the same operations.

Q: Can I switch tasks with a signal?

A: This is not currently supported in the software, however you may be able to accomplish the same goal by building each routine into one task, and using signals to command which sub-task is run and when.

Q: What happens when I hit the E-stop?

A: The 24V power will be disconnected from the arm. When this happens, the arm will fall a slight amount and the brakes will engage.

Q: To train an action group, can I give Sawyer the number of rows and columns and let it calculate the locations?

A: This is not currently supported in the 3.3 software version.

Q: Can I train a “safe zone” around my fixtures so that Sawyer does not bump into them?

A: No. But every action has a path into and out of that action. The robot will automatically generate paths during the task training, however the paths can be re-trained and modified to ensure the arms do not come in contact with any fixture in the workspace. See Paths for more information.

Q: Why is my calibration failing?

A: make sure that end of arm tooling has been removed from the robot before calibrating, the robot is level, and the arms are free from obstruction. See [Calibration] for troubleshooting tips.

Q: Why is the current pose invalid? It is within the work area on the task map.

A: Be careful that none of the 7 joints on the robot's arm are at or near a hard limit. If a joint is near a hard limit, the robot may not allow you to create a pick, place, or hold in this joint configuration. You can determine if the arm is near a hard stop or close to the screen if the crosshair icon on the user interface has been grayed out. Additionally, the joint indicators on the left of the screen in the workspace view show the joint limit level. If bar is full red, that join has reached a joint limit.

Q: Can I use vision to inspect the part?

A: The cameras in the robot are not currently available to be used for inspection. The cameras are used for the Robot Positioning System. Intera 3.3 allows you to create task using only hold actions and you can add external camera to do part inspection.

Q: How long is the count pulse?

A: The output signals from Sawyer are approximately 0.5 seconds long. You can verify the output is being sent from Sawyer to your external devices by connecting to Task Editor.

Q: Why are approach/retract and done grayed out in the advanced settings dialog?

A: This may mean that the approach and retract locations may be too far for the arm to reach. Be mindful that although an arm may be able to reach an Action location, it does not necessarily mean the approach and retract locations are valid. See Workspace Guidelines for more information.

Q: Can I set the number of pick attempts?

A: Yes. Sawyer's pick attempt value is defaulted to 2. After 2 missed picks, the robot will become confused. If more or less pick attempts are needed, you can change the default setting in the more options section of the Task Order Screen.

Signals

Q: How do I configure a PLC to communicate with Sawyer?

A: Sawyer communicates with the outside world through the Ethernet port on the back of the robot's torso via MODBUS TCP/IP. Your PLC must be either MODBUS enabled or digitally connected to a MODBUS device in order to successfully communicate, send, and receive signals to and from the robot. For information on connecting external devices to Sawyer, see the Configure Modbus sections.

Q: How long will a Done signal stay true after completing a Task, Subtask, Action?

A: In Intera 3.3, Done signals will remain true for the pulse duration set on that particular done signal. In general, the Done signal will remain true for no less than .5 seconds and can be monitored by using Monitor Mode.

Q: Why doesn't my Action run the second time through even though the Ready signal has always been true?

A: Check the count, which is only reset on the rising edge of Ready. Therefore, if you have a count of 1 and you leave Ready true, the Action will only happen once and the count will never be reset. If you’re using Ready to control a Pick, set the count to infinity. If you’re using Ready to control a Place and are using multiple subtasks, you can either set the count to infinity and use the Skip signal to move on to the next subtask or make sure that you cycle Ready false to true to reset the count.

Q: How do I use signaling and an external PLC to run Action Sequences out of order?

A: See here for more information on signals.

Q: If two input signals become true at the same time (e.g. Pick Ready and Subtask Skip), can I predict what will happen? Is there a way to understand what has a higher probability of getting chosen?

A: Relying on the robot’s behavior in this case is fundamentally unreliable system design. This is a classic synchronization problem and there is fundamentally no way to predict which signal will take priority. Whichever one Intera happens to notice first will take effect. Note that even in a procedural language, where you might be checking one signal then the other in a loop in order to decide what to do next, if they change at literally the same time you can’t predict which one will be noticed first. In situations where two signals might change at nearly the same time and predictable behavior is defined and required, we highly recommend that you use a PLC and logic that creates a window in which both signals are examined and an unambiguous decision is made, which is then communicated to and synchronized with Intera by asserting only one signal representing the required action

Q: Why is Sawyer confused when I try to run my imported tasks?

A: When importing tasks with signals, make sure the device names associated with each signal are renamed to the corresponding device communicating with the robot

Q: How long will a Done signal stay true after completing a Task, Subtask, Action?

A: In general, the Done signal remains true until the count on the element is reset. When using automatic reset, i.e., the Ready signal isn’t being used, Action counts are reset when their containing Subtask ends, whereas Subtask counts are reset when the Task completes. Due to the automatic resetting (e.g., in a Subtask with only one Place Action, the Subtask will end when the count is satisfied and then immediately reset the count) Done signals may only stay true for a short period of time, but in any case no less than 0.5 seconds.

Q: Why doesn’t my Action run the second time through even though the Ready signal has always been true?

A: Check the count, which are only reset on the rising edge of Ready. Therefore, if you have a count of 1 and you leave Ready true, the Action will only happen once and the count will never be reset. If you’re using Ready to control a Pick, set the count to infinity. If you’re using Ready to control a Place and are using multiple subtasks, you can either set the count to infinity and use the Do Subtask signal to move on to the next subtask or make sure that you cycle Ready false to true to reset the count.

Q: How do I use signaling and an external PLC to run Action Sequences out of order?

A: There are two main approaches to using signaling to run sequences out of order using an external PLC:
  1. Put multiple Action Sequences into single Subtask using the combine operation on the Task Order screen. Use Ready signals on the Picks to choose which Action Sequence to run.
    1. Counts should be set to infinity for all Picks and Places, since the single subtask never ends and the sequence is being controlled externally.
    2. The Ready signal for a Pick must be held true until the action completes. A way to reliably synchronize is to monitor the Increment Count signal and use that to clear Ready. An alternative approach would be to use the Increment Count on the corresponding Place, which would allow the Pick to repeat if the part was dropped. Which approach is better is highly application dependent.
  2. Put each Action Sequence into its own Subtask and use the Subtask Do Subtask signal to choose which Subtask to run.
    1. All Subtasks should have their own Do Subtask signal connected. In the idle case, all of the Do Subtask signals should be true.
    2. To run a particular Subtask, the PLC should set that Subtask’s Do Subtask signal to false. To operate reliably, the signal should remain false until the PLC receives a positive acknowledgement that the Subtask has started. This could be from the Start signal of the first Action, for example.
    3. In order to ensure that the Subtask doesn’t start again immediately upon completing the Action Sequence, Do Subtask should be cleared immediately upon receiving the indication that the sequence has started. Since Do Subtask is only looked at when no Action Sequence is running, this will allow the current sequence to complete and not restart.
    4. Do not use the Subtask Ready signal.

Q: If I invert an output signal (e.g.Done) and have not started the task, what will the output be and when does it become inverted?

A: Inversion takes place as soon as the modification is saved in the task and the changes have time to propagate throughout the system, typically a second or so.

Q: In the case of a HOLD -> PICK -> PLACE, why won't the robot go back to the first HOLD when PICK READY is not enabled?

A: Action Sequences are defined to not start unless there is an available Pick. This is to prevent the robot from getting stuck in a sequence when a better choice might come along. For example, a Do Subtask signal might want to end the Subtask, but that can’t happen in the middle of an Action Sequence.

Q: If two input signals become true at the same time (e.g. Pick Ready and Subtask Do Subtask), can I predict what will happen? Is there a way to understand what has a higher probability of getting chosen?

A: Relying on the robot’s behavior in this case is fundamentally unreliable system design. This is a classic synchronization problem and there is fundamentally no way to predict which signal will take priority. Whichever one Intera happens to notice first will take effect. Note that even in a procedural language, where you might be checking one signal then the other in a loop in order to decide what to do next, if they change at literally the same time you can’t predict which one will be noticed first.

Q: If I want to use a signal in order to look for an absent space on a conveyor, how would I do that?

A: You could attach a Part Presence sensor to the robot and a Ready signal to the Place location. All you need to do is invert the signal so that instead of acting as a parts presence sensor, it actually works as a parts absence sensor.

Q: Why can the Error In signal not be assigned to a subtask?

A: An Error in signal will stop the robot's current operation. Since the task will need to be restarted after the signal is triggered, the signal can only be assigned at the task level.

Q: Can an Error In signal be used as a safety stop?

A: See the page on Safety and Compliance for more information.

Q: Will any counts in my task be reset when a Pause signal is used?

A: No, the pause signal does not reset any of the procedures currently running in the task. When the Pause signal is removed, all task elements will pick up exactly where the were when the signal was triggered.

Q: Why can I not assign a Pause signal to a subtask?

A: The Pause signal is designed to temporarily stop all robot actions. Stopping only one subtask would allow other task elements to continue to run.

Q: When I use a Skip signal on a Hold, does the arm still move through the Hold location in the Baxter workspace?

A: Yes, the Skip signal will work slightly differently on a Hold compared to on a Sub-task. When it is applied to a Hold, the arm will still move to the Hold point, but will not wait for the given Hold time. When the Skip is on a sub-task, all actions in the sub-task will be disregarded until the signal goes low.

Q: I have the skip signal tied to a sub-task and when my external devices sends the signal, the robot doesn't skip the sub-task. What am I doing wrong?

A: Because the robot is only looking for a sub-tasks's Skip signal for a brief moment the very end of the previous sub-task, you need to make sure that the incoming signal is held True (latched) for the time that you need the robot to not perform that particular sub-task.

Q: What is the difference between using an inverted Skip Signal and using a Do Subtask Signal?

A: These two signals are similar in that they directly impact if a subtask will be performed or not. Inverting the Skip signal will act similarly to the Do Subtask. However the Skip signal can also be applied to a Hold action.

Q: Why is the robot showing confusion when I use the reset in signal?

A: Make sure that when the reset is applied, the gripper is not holding anything. If the gripper has a part in hand, and the task is reset, the robot will become confused.

Q: What is the difference between a Reset signal and a Reset Count signal?

A: The Reset signal can only be applied at the task level and is used to reset every element of a task while the Reset Count signal can be assigned to different task elements (except Holds) and will only Reset the count of the specified element.

Q: Why can the Reset Count signal not be assigned to a Hold?

A: Holds cannot have counts, so the Reset Count signal does not apply.

Q: Can the Done signal be applied to a task element that does not have an associated Count?

A: Yes. While the Done signal will trigger the count of a task element has completed, it will also trigger at first completion of the task element if there is no associated count.

Q: In what scenario would I use a Count signal over a Done signal?

A: A Done signal will only trigger when the count of a task element is full. A Count signal will be used when you want to send an output at each increment of the Count and not only when it is full.

Q: How is an Error Out signal different from a Confusion signal?

A: An Error Out signal is used for more critical errors with the robot than the confusion signal. The Confusion signal typically means that an object is missing or something is not trained properly while an Error means that there is a more serious failure.

Q: What can cause the robot to enter a state of confusion?

A: See the Confusion page for more information.

Q: Why can I not assign an Action Started signal to a task?

A: There should be no need to assign this signal to a task since the start of a task is never triggered internally, so there would be no need to send out a pulse notification that this has begun.

Q: When is the Action Ended signal triggered if I have a count assigned to a specific action?

A: The Action Ended signal is trigger when the action has completed and the count is full.

Q: Why would I need to send Reset Out signal when I manually reset the task running on the robot?

A: The Reset Out signal would be used to trigger any associated devices so that each device does not need to be manually reset.

Q: When is it beneficial to use an Active signal over a Start signal?

A: The Active should be used when a level signal is required for the duration of a Hold action. The start signal will only send a pulse when the robot arrives at the approach point for an action while the Active signal will remain trigger for the entirety of the action.

Specifications

Q: What make the robot safe?

A: See our page on Safety and Compliance for more information.

Q: What is Sawyer’s maximum grip force?

A: The Electrical Parallel Grippers maximum grip force (torque) is 10 lb / 4.4 kg

Q: What is Sawyer’s accuracy?

A: Sawyer's task repeatability is 0.1mm. By leveraging the compliance of the robot's arm and using fixturing, one can achieve the best accuracy. Please see this video for an example of using compliance to gain tight tolerances.

Q: How many Inputs and Outputs can Sawyer handle?

A: Sawyer can handle upwards of 99 Inputs and Outputs by using a MODBUS Remote Terminal Unit or PLC. The Moxa ioLogik E1212 Remote Terminal Unit for interfacing with the external world. It has 8 inputs and 8 output. For more information on the Moxa device, see Moxa_ioLogik_E1212


Q: What is Sawyer's payload?

A: Each arm has a payload of 4 kg (8.8 lbs). This includes the weight of the gripper and the object. Attempting to lift more weight may result in a hardware failure.

System

Q: Where is the robot's serial number located?

A: The serial number can be found on the back of the robot next to the power input cord. For more information, see Serial Number Information.

Q: How do I enter the Field Service Menu (FSM)?

A: See these detailed instructions on how to access the FSM.

Q: How do I set a Static IP address?

A: To set a static IP for Baxter, you'll have to access the Field Service Menu.

Q: What is Sawyer's IP Rating?

A: Sawyer is rated IP54. See Sawyer Datasheet for Sawyer's data sheet.

Can't find your answer?

Contact Support at Rethink Robotics with any other questions you may have.