Strange Phenomena

[rajsiyer]

Hi gang; Today, I saw something strange!. I was attempting communication on the Unitelway port with X-Way driver manager version 7.7 & the application being developed on PL7 ver 4.3. The PLC was a TSX 57103 version 5.9. The programming device was a PC with WIN98. Even though the PL7 & XWAY manager were meant for WIN98... No communications took place even though I tried everything. I was using an ADAM make RS485/232 convertor, on the AUX port. Ominously, the ERR light remained steady on the PLC despite repeated resets! In frustration, and perhaps fearing damage to the PLC, I moved everything to another PC with WIN-XP. I found communication getting established rather easily. In fact, comm. was established readily even despite the fact that PL7 ver 4.3 does not support TSX57103 ver 5.9!. Even if the baudrate was wrongly configured in the X-way driver, (proper parity, data and stop bits are essential) The PLC connected in a trice. I think its because of some difference in the way the COM port is managed in WINXP, as compared to WIN98. XP manages the handshake at com port better! So next time you have a connecting problem try XP. Regards, & best wishes that this info is of some use to at least some readers. Raj S. Iyer

[Wize]

I have had the same sort of problems with Siemens PLCs and Win98, but that was a Dos program and 98's time slicing on Dos programs was a bit on the jumpy side. Even full screen it would drop out. Probably ok for most applications, but if the program handled its own comms routines rather than letting the system do it the data would be in burst instead of a smooth flow. Could be the same with those drivers. Also its likely to be a faster PC, so less likely to give the driver some odd sized time slices.