Check the convertor:
If there is an RS232 to RS485/422 converter being used, then check to see that it is setup correctly, things to check are:
- Check the wires haven’t fallen out or broken off!
- RS485: does the converter need to be set to 2-wire or 4-wire mode or is this done by jumpering across from Tx to Rx ?
- Power requirements: Is the convertor’s power supply working? Check with a Voltmeter
- LEDs: are there LEDs indicating comms traffic? Are they flashing Tx but not Rx? See here for a note on how often they should flash.
- If the RS232/RS485 converter is self-powered, does the 9-pin port on the PC supply enough power? Some laptops don’t, and some USB-to-Serial convertors don’t.
- If there are no LEDs on the converter itself, you can make some to verify that SpecView is talking out to the instruments, see here.
- Does the converter have Automatic Send Data Control? If not, then it probably won’t work! See here for more details on this. Note: “KD485” convertors need to be “KD485 ADE” versions to work.
If there is a USB-to-Serial converter in use, you can check to see if that is working properly