Template:A-Series/Troubleshooting/Closed-Loop

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Troubleshooting A-Series Closed-Loop Motion Devices

The following sections contain tips for troubleshooting common problems with the A-Series devices.

If the device is unable to communicate, and it is operating erratically, a manual factory reset can be performed as a last resort through the following steps:

  1. Power Off the device
  2. Push and hold the knob for the first Axis (if applicable)
  3. Power On the device
  4. Continue to hold the knob in until the Blue LED is lit (~5 seconds), release the knob.

The device has been returned to its factory defaults and can be configured per the steps in Initial Setup.

Front Panel Indicators

Green LED On
The device is powered on and operating normally
Green LED Fades In and Out
The device is parked.
Issue a tools parking (T:65) unpark command, or home (T:1) the device.
Green LED Flashes Slowly
The operating conditions of the device are outside of the recommended range.
This will occur when the supply voltage is either over or under the recommended range, the internal temperature has exceeded the set limit or the driver has disabled. Check the following:
  • The input voltage within the operational range of the device. This can be read from the device with the get system.voltage command.
  • The device temperature is within range. This can be read from the device with the get system.temperature command.
  • The driver is not disabled. If the driver is disabled the result of the warnings command will contain the FD flag.
Green LED Off
The device is not powered.
Check the supply connections and power adaptor for correct operation.
Red LED On or Flashing.
A critical error has occurred.
Please contact Zaber Technical Support.
Blue LED On or Flashing.
The device has slipped or stalled.
Please see the Slipping and Stalling section below.
Yellow LED Always Off or Flashes but No Reply.
There are communication errors.
Please see the Communication Errors section below.

Manual Control

Turning the knob either way results in no movement
The knob may have been disabled.
Check that the knob.enable (T:107) setting is correct.
Restore the default parameters through the system restore (T:36) command.
The device won't cover the full range of travel.
The device hasn't been homed.
Turn the knob anti-clockwise until the device reaches the fully retracted position (closest to the motor). The device will home and the full range of travel available.

Unexpected Behaviour

The device doesn't respond to a move command.
The device needs to be homed before use.
Send the home (T:1) command.
The device is moving on its own and running against the ends of travel.
The position encoder has de-synchronized.
Reset the device by power cycling it or sending system reset (T:0) command, then re-initialize it with the home (T:1) command. Ground the device and avoid operation under a statically noisy environment.
The device is moving very slowly. It used to move faster.
The speed settings may have been changed inadvertently.
Send a system restore (T:36) command.
The device makes louder than normal noise during travel and is frequently slipping.
This condition happens if the thrust needed is more than the thrust available from the device.
Check the following:
  • The force on the device is less than the maximum thrust.
  • The voltage using the get system.voltage command. Voltage less than the specified voltage for the device will reduce the device’s maximum thrust.
Test the following:
  • Try a slower target velocity. Stepper motors produce more thrust when moving slowly.
  • Try a lower acceleration and deceleration.
  • Clean the screw and lightly re-grease it with a grease that does not degrade plastics.
The device has repeatability errors smaller than 4 full steps.
If steps aren't being skipped, friction or loose parts may still cause some variation when returning to a position.
Please contact Zaber Technical Support.
The device doesn't cover the full range of travel, or runs into the end.
A setting might have been inadvertently changed.

Communication Errors

There is no communication with the device, the Yellow LED does not come on or flash.
There are several things should be checked:
  • Make sure the correct serial port is selected. Try selecting other serial ports in the software.
  • Check the baud rate, hand shaking, parity, stop bit, etc. when configuring the serial communications software. The required settings are listed in the RS232 Communications section above.
  • Make sure there are no bent pins in the ends of all the data cables
  • Make sure the device is powered, the Green LED should be on.
  • If the computer is a laptop running on batteries, try plugging in the power. Some laptops disable the serial ports when running on batteries.
  • Make sure a null modem adaptor or cable is not being used.
  • Make sure the correct adaptors(if any) are being used. Refer to the pinouts in the RS232 Communications section above.
  • If the problem encountered when trying to control the device with custom software, try using one of the demo programs from the Zaber website to verify that the hardware is functioning properly.
The yellow light comes on briefly when sending a command, but the device does not move and does not reply.
Check baud rate, hand shaking, parity, stop bit, etc. are set as per the RS232 Communications defaults.
The device numbers may not be what is expected, issue a system renumber (T:2) command. Make sure that the computer does not transmit anything else while the devices renumber.
If using the binary protocol, check the following:
  • 6 bytes are transmitted and that the device number and command are valid.
  • The software does not transmit any control characters such as line feed and spaces.
  • That the serial port is not configured with a termination character (it often defaults to linefeed).
If problems are encountered when using custom software, try using one of the demo programs from the Zaber website to verify that the hardware works.
The device does not behave as expected when software sends it a series of commands.
The computer might be set to Unicode. This is common for languages that use non-Latin based characters. Go to Control Panel/Regional and Language Options/Advanced. Select a language for non-unicode programs. This should be English or another Latin based character language.
Check what is being sent out of the serial port. stackoverflow.com has a list of some tools to monitor serial ports.
In Binary mode, the device does not send replies but otherwise works.
Auto-reply might have been disabled via T:101.
Send a system restore (T:36) command.
If the problem is encountered when trying to control the device with custom software:
  • Use a demo program from the Zaber website to verify that the hardware is functioning properly.
  • Make sure that the receiving part of the code or commercial package is correct.
  • Check the serial port settings are correct.
  • Check connectors for bent or broken pins.
In Binary mode, the device sometimes returns fewer than 6 bytes.
This typically indicates a problem with the serial port settings. Some serial ports are set to automatically recognize and remove specific control characters such as carriage returns when they appear in the RS232 receive buffer.
Check the settings are correct and not removing or replacing characters.

Slipping and Stalling

The device moves smoothly, but only moves for a short time then stops. The blue LED is flashing but the device is not actually slipping or stalling
The internal encoder counter needs to be re-initialized. Reset the device by power cycling it or sending system reset (T:0) command, then re-initialize it with the home (T:1) command.
Ground the device and avoid operating it under statically noisy environment.
The device makes noise but does not move. Blue LED is flashing.
The device is stalling.
Try removing all external loads. If the device now extends and retracts normally, the problem is excessive load. Try to reduce the load and ensure the load is less than the maximum thrust. A higher thrust or torque can be achieved by lowering the speed of the device using the maxspeed (T:42) setting.
If a device is stalling with no external load at default speed and acceleration settings then it requires servicing.