Hello. I am interested in comments anyone has regarding inconsistent behavior of different versions of Thermotron 8800 controllers over RS232. Here's my story...
I have software built on LV2014 that has been in use on a variety of test stands for quite some time. It works fine at 9600 baud rate with standard settings on any 8800 controller with software version 2.xx on it. The newer 8800 controllers that have been coming in are in the 4.xx version range. The newer ones have been having issues with VISA sessions disconnecting at 9600. We have been able to get around this by turning the baud rate up to 57600. But on the controllers that needed 57600, the VISA session still occasionally disconnects. It was rare enough that I gave up trying to figure it out.
Recently we had a 2.xx controller fail and replaced it with a new 4.xxx version. This one is the worst yet. It doesn't like any baud rate. I can get a thermal started at 57600, but it won't last long. We tried other known good PCs, cables etc. This one just doesn't like RS232.
When I look at the Thermotron log of commands it receives, there are some garbled characters in addition to what the stand sent out.
So I decided to try switching to TCP/IP. It works great. I've had it cycling for two days now with no issues at all. So that's the answer I'm going with.
But people are asking why after all these years of RS232 working fine would we need to switch to Ethernet for newer controllers.
Anyone have similar experience with these?