Hi guys, I really can do with some good advice how to solve this one.

For one, the PLC is an O7KT97 from ABB programming which I have no trouble. But it is linked to ABB's Scada called SCADA PORTAL. This is through an ordinary RS232 cable. There is no problem with connecting the PLC to the PC.

However, when connecting to SCADA, the link is horrible. It almost never connects. The SCADA is served by a Codesys OPC server which polls some 1000 symbol items in the PLC. The Update rate for this OPC server is some 200ms default setting! I despair how can this thing work if at all. The PLC program is large. There are more than 100 Discrete IOs and about 40 analogs.

My question is whether the serial link between the PLC and scada can take this load. Anybody ever has a similar experience?.


Thanks a million to anybody who thinks about this situation and advises me sensibly,

With best wishes, I remain,

Raj S. Iyer