OT: Clear and Trial (Tri Start) Process

Hi All,

Im hoping to get some insight from you guys regarding isolation procedures and diplays.

We are building functionality into our PLC code and SCADA to assist in the isolation of equipment and tracking and verification.

Sequence

1. Field tech isolates equipment in substation.
2. Plant Controller puts equipment in maintenance mode.
3. Field tech then goes to local equipment push button and tries to start equipment.
4. Controller gets a display on SCADA in control room that equipment is isolated.
5. When Isolator input changes the state is cleared.

In a hard wire maintenance circuit (Bypass PLC) its pretty simple how this would work since you will physically never energise the "coil".

What happens in the case you have start/stop commands being issued over communication protocols. Do you still need to issue the start command to the device or is verification in PLC sufficient?

Im thinking of cases where potential intelligent started device would go into fault mode because it is trying to start and its not detecting a load.

Any experience/advice thoughts will be appreciated.

And a final greeting to all for the festive season.



Thanks

you should still attempt to start it, as a simple label.wrong or mistake by the guy locking out and you have a problem. You attempt to start while in maintenance mode ad it fails to start then it can display you have verified isolation...

Thank you for the feedback , i agree with this and we will implement using this method.

My worry is that certain intelligent starters might go into a fault mode, but we will test the relevant equipment to determine how it behaves under these conditions.

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