M580 redundant CPU stop logic execution

[mohanchandra113]

Dear All,

We have an architecture, have 10 M580 Hot-Standby Systems in ring architecture and communicate with redundant Plant Scada via OFS communication. Sometimes we face an issue that one of M580 system stop logic execution (Does not take any command from SCADA and also the section under MAST not executing, it holds the last values). But the CPU does not go to either STOP or HALT mode. LED status on both CPUs found OK and in RUN mode. Nothing found also in diagnostic viewer. After downloading the program in both controllers, system start again. We cannot understand why it is happening. 

Controller: BMEH4040, PV:26, SV: 3.22

Software: Control Expert 15.2 with DTM of 15.3.

[Mac]

Do you have this options turned on?

10 M580 HSBY and how many RIOs to each? We had similar issue but solved it.

[mohanchandra113]

'Allow Logic Mismatch' -- Not Checked.

'Number of Modification' -- 0

'CPU Execution' -- First Section

'Controller A Online' -- True

'Controller B Online' -- True

Number Of RIO -- 3

[Mac]

RIO Addressing and PLC Download Recommendations

Make sure that RIOs in different HSBYs do not share the same physical address if they are in the same IP subnet.

We encountered an issue in a setup with 5 HSBYs, each containing RIOs with addresses 1–5. During downloads on different HSBYs, the system would occasionally associate a RIO from another configuration, leading to incorrect behavior.

Recommendation:

• Assign unique physical addresses to RIOs across all HSBYs.

• Use the rotary switch on each RIO (if available) to ensure the physical address is different for every RIO in the same subnet.

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PLC Download and Redundancy Settings

Additionally:

• Enable “Allow logic mismatch”

• Set Number of modifications = 20

These settings help prevent the PLC from stopping:

• during downloads

• when switching between primary and standby controllers