We are having Triconex PLC with HMI and connected to DCS by Mod bus.we get the HMI frozen so many time and the only way to solve thi problem was to reboot the HMI.
Anyone of you have an answer how to solve this issue?
Modbus is a protocol ( how the 1's and 0's are put together to make a message), and it is doubtful that is the problem.
Most likely the problem is the handshake going on between the 2 machines. Handshaking can be 1. None, 2. Xon/Xoff (a message saying shut-up, I am busy), or 3. Hardware (DTR/DSR, and RTS/CTS).
Check the documentation on both units, and set them the same. Don't forget to check the cable pin-out as well. More times than I can count both units said "No Handshaking", but that only meant that they did not change the state of theiroutgoing pins, they still needed the corresponding inputs in the correct state. Sometimes that is a jumper on a board, sometimes it is wiring on the connectors at either/both ends of the cable.
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TANSTAAFL (If you don't know what that means, Google it - yourself)
If HMI and PLC talk OK then your comms are probably OK. If the HMI runs for a period of time then hangs it is probably not the Modbus link (however don't discount this altogether- I agree with the previous post check the obvous stuff like your cable). Wiggle it about and see if you can get it to fail or hang (don't break it though ;-).
Does the HMI seem to run OK for a while then gradually the updates get slower and slower until finally it hangs? Do you have something that is hogging the PC resources. Does the SCADA application grab more of the PCs resource the longer it runs (if I remember correctly that is called memory creep or memory leakage) Check with the HMI supplier if this is a known problem? Are you running any other applicaitons on the same HMI that can hog the system resources?
Are the operators opening multiple windows where most of them are trend pages? and then open some more without first shutting down the previous ones?
Do you have enough RAM or is your page file set large enough?
Reboot - Do Ctrl Alt Del, Task Manager and check Performance - take note of the numbers and check again after a day (or however long yours lasts).
Can you check the driver for update times to see if it gets slower as the machine runs?
Also check your harddrive - is it full? Is the alarm event logger set to log loads of entries and filling up the hard drive? If so you need to set it so that after so many entries they drop off the end or after a month they auto save to a back up. Either way it should be limited to how much hard drive space it can consume (the best way to do that is to log alarms and events to a different drive from the root where the SCADA application runs from)
If it is a logging thing you need to refine it by deleting stuff surplus to requirements and only log the stuff you need to.
Does this happen after an event (e.g a process shutdown) where you get an alarm flood for example.
Another common one is - if your analogue tags don't have a deadband set then they will be logging every fluctuation in signal. Set a deadband so it only logs important changes.
Some other stuff to consider is the loading on the comms driver - how often is it polling? Are you set to poll every tag all the time - if so maybe stagger them so that e.g temperatures that change slowly only get polled every so often say every 30seconds etc.
HMI communication fail
Re: HMI communication fail
