I recently wrote a simple java driver to communicate with Omron devices (CJ1 and CJ2) via the FINS protocol over UDP.
I've installed this software at a number of my client's sites and it works well most of the time.
However, I've encountered a number of instances where a CJ1 device will consistently return what looks like a valid response but every memory register I request will return zero.
I've deployed the software to 5 sites with identical configurations. The sites have one CJ2 device and one CJ1 device. The CJ2 devices work exactly as expected. Three of the CJ1 devices work exactly as expected but the other two have this issue where every value is zero all of the time. This issue is not intermittent at those sites - I have never had it return anything other than a zero for any memory register for a CJ1 device at those two sites.
Example:
TX: [80, 00, 02, 00, 0a, 00, 00, c9, 00, ff, 01, 01, 98, 00, 00, 00, 00, 64]
RX: [c0, 00, 02, 00, c9, 00, 00, 0a, 00, ff, 01, 01, 21, 08, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00]
