Troubleshooting/A-Series Closed-Loop Motorized Devices

Troubleshooting A-Series Closed-Loop Motion Devices

Symptom	Check
Nothing happens when I turn the knob either way.	Manual control may have been disabled. Issue the Restore Settings (Cmd 36) command or enable the knob using Set Knob Disabled Mode (Cmd 107) with data 0.
Two or more devices both respond to commands sent to device 1.	Most devices are shipped with their device number set as 1. If you connect the devices through Zaber Console, you will be prompted to renumber them. If you aren't able to install and open Zaber Console, send the Renumber Instruction (command 2) in the software you are using to set all of the device numbers to different values.
Nothing happens when I send a move instruction.	The device needs to be "homed" first. You must issue the Home (Cmd 1) command after power up to initialize the device.
Device does not move when sending an instruction or turning the knob.	Check whether the green LED is fading in and out slowly. If so, the device is Parked. Send Set Park State (Cmd 65) with data 0 to unpark the device, or Home (Cmd 1) the device.
The device can move smoothly, but only moves for a short time then stops. Blue LED is flashing.	If the blue LED is flashing and Slip Tracking or Unexpected Position responses are received, but the device is not actually slipping or stalling, the internal encoder counter may need to be re-initialized. Reset the device by power cycling it or sending Reset (Cmd 0) command, then re-initialize it with the Home (Cmd 1) command. Ground the device and avoid operating it under statically noisy environment.
The device is moving on its own, and is running against the ends of travel.	The internal encoder counter may need to be re-initialized. Reset the device by power cycling it or sending Reset (Cmd 0) command, then re-initialize it with the Home (Cmd 1) command. Ground the device and avoid operating it under statically noisy environment.
Stall condition: The device makes noise but does not move. Blue LED is flashing.	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. You can achieve higher thrust or torque by lowering the speed of the device using the Set Target Speed Instruction (command 42). If a device is stalled with no external load then it requires servicing.
There is no communication between the computer and my Zaber device, the yellow light does not come on or flash.	There are several things you should check: Make sure you have the correct serial port selected. Try selecting other serial ports in the software. To ensure that your serial port is working properly, you can connect the send and receive pins of the serial adapter without connecting any devices. Use a wire to connect pins 2 and 6. Your software should echo a reply every time you send an instruction. You can view the pinout diagram here. Check the baud rate, hand shaking, parity, stop bit, etc. when configuring your serial communications software. The required settings are listed in the Control Through The RS-232 Serial Port section above. Also make sure that your serial port is not configured with a termination character (it often defaults to linefeed). Make sure there are no bent pins in the ends of all the data cables Make sure the power supply is working. The dc plug should measure 12 - 48 Vdc when it's not plugged into the device. Make sure the power plug is plugged in all the way. If your device has LEDs, the green LED should light. If your computer is a laptop running on batteries, try plugging in the power. Some laptops disable the serial ports when running on batteries. Make sure you do not have a null modem adapter or cable in the line. The serial to mini-din adapter comes in many varieties and many have different pin connections. Check the adaptor for continuity on the proper pins by consulting the adaptor pin-out diagram above. If you encounter the problem when trying to control the device with your own software, try using one of the demo programs from our website to verify that the hardware is functioning properly.
My device is behaving strangely. It responds to some commands as expected but not to others.	Send a Restore Settings Instruction (command 36). A setting might have been inadvertently changed. If you have a T-MCA or T-CD series stepper motor controller, note that a data value should be entered with the Restore Default Settings Instruction corresponding to the Peripheral Id of the device you are controlling. Your 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.
The device is moving very slowly. It used to behave differently.	The speed settings may have been changed inadvertently. Send a Restore Settings Instruction (command 36).
Green LED does not come on	Check the A/C wall plug, the voltage adaptor and its connection to the device. If the power is coming over the data cable, check the mini din connector for bent or broken pins.
Green LED flashes at 2Hz	The power supply voltage or temperature is out of range. It may either be too low or too high.
Green LED fades in and out slowly. Device does not move when sending an instruction or turning the knob.	The device is Parked. Send Set Park State (Cmd 65) with data 0 to unpark the device, or Home (Cmd 1) the device.
The yellow light comes on briefly when sending a command, but the device does not move and does not return codes.	Check baud rate, hand shaking, parity, stop bit, etc. Make sure that your software does not transmit any control characters like line feed, spaces or something else. The device numbers may not be what you think they are. Issue a renumber command, make sure that the computer does not transmit anything else while the devices renumber. Check that you transmit 6 bytes and that the device number and command are valid. If you encounter the problem when trying to control the device with your own software, try using one of the demo programs from our website to verify that the hardware
The red LED is on or flashing	Device has lost its settings, or an error has occurred. Please contact technical support.
The device does not send replies but otherwise works.	Auto-reply might have been disabled via Set Auto-Reply Disabled Mode (Cmd 101), try sending a Restore Settings (Cmd 36) command. If you encounter the problem when trying to control the device with your own software, try using a demo program from our website to verify that the hardware is functioning properly. Make sure that the receiving part of your code or commercial package is correct. Check baud rate, etc. Check connectors for bent or broken pins.
The device sometimes returns fewer than 6 bytes.	This problem usually indicates a problem with the settings for your serial port. 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. When this happens, it appears as though the device has not sent enough bytes, but really the controlling computer has just removed some before you could read them. You will need to change the serial port settings to fix the problem.
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 that the force on the device is less than the maximum thrust. Check the voltage using the voltage command. Voltage less than the specified voltage for the device will reduce the device’s maximum thrust. Try a slower target velocity (command #42) as stepper motors produce more thrust when moving slowly. Lead screw conditions greatly affect the performance of linear motion devices. Dirt, damaged threads, no grease or too much grease will degrade performance and may contribute to a stall. A black residue appears on the lead screw after extended use. This can increase friction and reduce thrust. Clean the screw and re-grease it with a grease that does not degrade plastics. In general if you try to move a large payload or have a large static axial load (like lifting something vertically) you will have more problems. For vertical motion, the use of a counterweight, spring or rubber band can help reduce the static load and improve the performance of the device. The default value of the acceleration and target velocity are good for small to medium loads and medium speeds. For very light loads and higher speeds, or heavy loads at lower speeds, these parameters can be tuned. Trial and error is the best tuning technique.
The device has repeatability errors smaller than 4 full steps.	If you're not skipping steps, friction or loose parts may still cause some variation when returning to a position.
The device does not behave as expected when software sends it a series of commands.	It can be challenging to track down problems in a complicated script or other software. In addition to the standard techniques of debugging any software, it's also helpful to see exactly what bytes are being sent and received on the serial port. There are several tools available to display the raw data from a serial port, and stackoverflow.com has a list of some.