When changing out PCs in your Multitrac or Mentor system you may run into an issue where devices are not talking on the serial link to the PC. Depending on the MOXA card installed on the PC, your serial port communicates over pins 1 & 2
or 3 & 4. An adapter,
09BC09NRBT, can be purchased to facilitate the changeover. Use the instructions below to help guide you through the changes.
If your Moxa Card has a cable with 4 connectors on it, know that there are 2 possible pinouts. The cable marked with P1, P2, P3 and P4 uses a different pinout than the cable marked with Roman Numbers I, II, III, IV.
In every case you should have the cable connector 09BC09NRBT (you may need 4) in case you need to change the cable pinout. Obviously, you cannot change the MOXA cable since it is molded together. So, you would change the D-sub 9 connector on the gray cable that leads to the terminal blocks.
This D-Sub 9 Connector below is suitable for this conversion.
What is your original wiring?
Check your connector and locate which pins are used on your plug. The plug shown below is using pins 3, 4, and 5. Older PC cables may have used pins 1 and 2 instead of pin 3 and 4. Older MOXA card used a 4-port cable connected with one connector to the Moxa card and split into 4 individual 9 pin connectors. These probably used pin 1 and 2 in the serial cable. PCs with the Moxa connector onboard the PC currently use pins 3 and 4 for serial communication. If this is your case, you need to rewire the connector using the new plug with internal screw terminals.
Cut the Cable and Connect the New Plug
| Older Serial Configuration | Current MOXA Configuration |
|---|
| Pin 1 (Serial low SRL - ) | Pin 3 (Serial high SRL + ) |
| Pin 2 (Serial High SRL +) | Pin 4 (Serial low SRL - ) |
| Pin 5 (Ground) |
See the pictures for help with wiring.
Older Serial Configuration
Current MOXA Configuration
My Connector Doesn't Fit
The new connector is thicker on one side. This will require the chassis mounted ports to be flipped over. The face plate and connector both need to be flipped to keep the port number the same. You will need a T-8 torx-bit and a flat head screwdriver.
