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RS232 Troubleshooting for 6000 Series Products


Above posting also has step-by-step instructions on connecting and screen captures on using Motion Architect software.

This guide serves as an aid in establishing RS232 communication with with 6000 Series stand-alone products only (not bus-based 6000 products), as well as troubleshooting most commonly seen RS232 communcation problems. Before proceeding, make sure that you have downloaded the Motion Architect V3.5 software package.

If you do not have Motion Architect V3.5, you can download it from from Support & Downloads

  1. Set up the correct connections between the PC and the Compumotor Product:

    9 Pin PC Connection Compumotor Product 25 Pin PC Connection Compumotor Product
    Pin 2(Rx) Tx Pin 2(Tx) Rx
    Pin 3(Tx) Rx Pin 3(Rx) Tx
    Pin 5(GND) GND Pin 7(GND) GND

  2. Be sure to choose the correct COM port of the computer in Motion Architect----TERMINAL, SETTINGS, SERIAL PORT. If the SERIAL PORT is grayed out and it cannot be "clicked", you first need to disconnect (TERMINAL, TRANSFER, CONNECT), then you can choose the other serial port. After this port is chosen, reconnect (TERMINAL, TRANSFER, CONNECT).

  3. Kill any running programs by typing !K. Then, type a simple command such as !TAS into the Motion Architect Terminal screen.
    1. If you get a response: *TAS010101.. then you are successfully communicating.
    2. If you do not see the letters !TAS as you type, go to Step 4.
    3. If you can see the letters !TAS as you type, but you get no response, go to Step 5.

  4. Problem: No Echo Of Commands
    1. Double check the connections between the computer and the Compumotor product (see Step 1). The Rx and Tx wires could be swapped. Complete a continuity check on the cable according to the table in Step 1.
    2. The communication echo could be turned off. Type the following three commands in the Terminal screen of Motion Architect:


      After issuing these commands, go back to Step 3.

    3. You may have selected the wrong COM port in Motion Architect. Change the COM port under the SETTINGS menu - See Step 2.
    4. Perform a "Loop Back" test to verify that your serial cable is working:
      • Disconnect Rx and Tx on the Compumotor product
      • Short Rx and Tx wires together
      • While these two connections are shorted, type any characters
      • If you do not see any of these characters: Either you have a bad cable, you chose the wrong COM port, or your COM port is damaged.
      • If you do see characters, then Rx and Tx are swapped. Reverse the Rx and Tx wiring connections, then go back to Step 3.

  5. Problem: Commands echo, but no response is returned by the Compumotor product
    1. You chose the wrong COM port. Try the other COM port if your unit has one (go back to Step 2).
    2. You may have a short in the cable. First, perform a continuity test to verify the connections (See Step 1)
    3. Disconnect the RS232 cable from the Compumotor product. Then type some characters into the Terminal. If you continue to see your typed characters appear on the screen, then your RS232 cable has an internal short. To test, ohm the RS232 cable by measuring resistance across the Tx and Rx wires. If you see an open circuit between Tx and Rx when measuring resistance, the cable is not shorted.
    4. The unit or PC port could be damaged.


NO LUCK? Other Possibilities:

1) Try connecting your product to another PC, and repeat the aforementioned process.

2) Is the computer power cord and Compumotor product's power cord plugged into the same AC outlet? In some cases, a ground potential between two AC outlets has caused an RS232 port failure. Plug both into the same AC outlet. Try communicating with the other COM port, if the device has one.