T-Series/Commands/Set Closed-Loop Mode

Set Closed-Loop Mode - Cmd 118

Warning: This is an "include" page. As such, its contents may be included in multiple other pages. To see a list of all pages that include this page, click on "What links here" in the bottom left navbar. If you make changes to this page, be sure that your changes are appropriate to all pages on which this content will be included. You are also encouraged to review our Zaber Wiki Editing Guidelines. This header will not be included in other pages.

Instruction Name	Set Closed-Loop Mode
Applies to	A-Series and X-Series motorized closed-loop devices
Firmware Version	6.xx
Command Number	118
Command Type	Setting
Command Data	Closed-Loop Mode
Reply Data	Closed-Loop Mode
Safe to retry?	Yes
Returns Current Position?	No
Persistence	Non-Volatile
Summary	Sets the closed-loop (slip, stall, and displacement detection and recovery) control mode for encoder embedded devices.

This command configures the closed-loop behavior of a device, determining its reaction to slips, stalls, and displacement conditions. Behavior and available settings vary by encoder type.

Devices with Motor Mounted Encoders

Closed-Loop Mode	Slip Detected1	Stall Detected2	Displaced While Stationary
0 - Disabled	No action.	No action.	No action.
1 - Passive Mode	Slip Tracking (Cmd 12) reply is sent. Blue LED remains on while slipping.	Blue LED cycles on and off every two seconds.	Unexpected Position (Cmd 13) replies are sent. Blue LED flashes twice per second.
2 - Stall Detection	Slip Tracking (Cmd 12) reply is sent. Blue LED remains on while slipping.	Device stops after a duration specified by a Stall Timeout (Cmd 120) and an Unexpected Position (Cmd 13) reply is sent. Blue LED cycles on and off every two seconds.	Unexpected Position (Cmd 13) replies are sent. Blue LED flashes twice per second.
3 - Position Correction (Default)	Slip Tracking (Cmd 12) reply is sent. Current Position (Cmd 60) is updated based on encoder position. Blue LED remains on while slipping.	Device stops after a duration specified by a Stall Timeout (Cmd 120) and an Unexpected Position (Cmd 13) reply is sent. Blue LED cycles on and off every two seconds.	Unexpected Position (Cmd 13) replies are sent. Blue LED flashes twice per second.
4 - Stall Recovery	Slip Tracking (Cmd 12) reply is sent. Current Position (Cmd 60) is updated based on encoder position. Blue LED remains on while slipping.	Device stops and then resumes after a duration specified by a Stall Timeout (Cmd 120).	Unexpected Position (Cmd 13) replies are sent. Blue LED flashes twice per second.
5 - Displace Recovery	Slip Tracking (Cmd 12) reply is sent. Current Position (Cmd 60) is updated based on encoder position. Blue LED remains on while slipping	Device stops and then resumes after a duration specified by a Stall Timeout (Cmd 120).	Slip Tracking (Cmd 12) replies are sent. Blue LED flashes twice per second. Restores to its original location after remaining stationary for a duration specified by a Stall Timeout (Cmd 120) . Once recovered, an Unexpected Position (Cmd 13) reply is sent.

^{1 - A stepper motor has slipped when the encoder feedback lags the Current Position - Cmd_60 by two full steps of the motor or more.
2 - A device has stalled when the motor has failed to make progress towards the targeted position for the Stall Timeout - Cmd 120 period.}

Devices with Direct Reading or Linear Encoders

Closed-Loop Mode	Approaching Targeted Position	Stall Detected3	Displaced While Stationary
0 - Disabled	No action.	No action.	No action.
1 - Passive Mode	Not available.	Not available.	Not available.
2 - Stall Detection	No action.	Device stops after a duration specified by a Stall Timeout (Cmd 120) and an Unexpected Position (Cmd 13) reply is sent. Blue LED cycles on and off every two seconds.	Unexpected Position (Cmd 13) replies are sent. Blue LED flashes twice per second.
3 - Position Correction (Default)	Device makes small movements to try to match the encoder's position to the targeted position. If the encoder's position doesn't match the targeted position after the adjustments, Current Position (Cmd 60) is updated to match the encoder's position.	Device stops after a duration specified by a Stall Timeout (Cmd 120) and an Unexpected Position (Cmd 13) reply is sent. Blue LED cycles on and off every two seconds.	Unexpected Position (Cmd 13) replies are sent. Blue LED flashes twice per second.
4 - Stall Recovery	Device makes small movements to try to match the encoder's position to the targeted position. If the encoder's position doesn't match the targeted position after the adjustments, Current Position (Cmd 60) is updated to match the encoder's position.	Device stops and then resumes after a duration specified by a Stall Timeout (Cmd 120).	Unexpected Position (Cmd 13) replies are sent. Blue LED flashes twice per second.
5 - Displace Recovery	Device makes small movements to try to match the encoder's position to the targeted position. If the encoder's position doesn't match the targeted position after the adjustments, Current Position (Cmd 60) is updated to match the encoder's position.	Device stops and then resumes after a duration specified by a Stall Timeout (Cmd 120).	Slip Tracking (Cmd 12) replies are sent. Blue LED flashes twice per second. Restores to its original location after remaining stationary for a duration specified by a Stall Timeout (Cmd 120) . Once recovered, an Unexpected Position (Cmd 13) reply is sent.

^{3 - A device has stalled when the motor has failed to make progress towards the targeted position for the Stall Timeout - Cmd 120 period.}

Voice Coil Devices

Closed-Loop Mode	Stall Detected4	Displaced While Stationary5
0 - Disabled	Not available.	Not available.
1 - Passive Mode	Not available.	Not available.
2 - Stall Detection	Not available.	Not available.
3 - Position Correction	Device stops after a duration specified by a Stall Timeout (Cmd 120) and an Unexpected Position (Cmd 13) reply is sent. Current Position (Cmd 60) is updated to the stopped location, matching the encoder's position. Blue LED cycles on and off every two seconds.	Current Position (Cmd 60) is updated to the new location, matching the encoder's position. An Unexpected Position (Cmd 13) reply is sent. Blue LED flashes twice per second.
4 - Stall Recovery	Current Position (Cmd 60) is updated to match the encoder's position. Device continues to approach its targeted position.	Current Position (Cmd 60) is updated to the new location, matching the encoder's position. An Unexpected Position (Cmd 13) reply is sent. Blue LED flashes twice per second.
5 - Displace Recovery (Default)	Current Position (Cmd 60) is updated to match the encoder's position. Device continues to approach its targeted position.	Device always restores to its original location.

^{4 - A voice coil device is considered to have stalled when the motor has output its maximum force for over the Stall Timeout (Cmd 120) period during a position controlled movement.
5 - A voice coil device has been displaced if it has been held at a new location for the Stall Timeout (Cmd 120) period in position control mode.}

Closed-loop (slip/stall/displacement recovery) mode can be enabled on devices with a built-in encoder.

To use closed-loop modes with a third party encoder, use ASCII mode to configure encoder.mode and all encoder related settings. Set encoder.dir so that encoder.count increments in the same direction as pos. Adjust cloop.steps and cloop.counts to reflect the correct ratio between motor full steps and encoder counts.