Best practice LOTO
We have a factory using AC450 and 800M controllers.
When doing lockout on a motor, locking the safetyswitch off, we need to do a start from the faceplate to check for remaining energy.
If MOTCON is interlocked, what is the best practice to check for remaning energy?
Give all operators permanent tune permission to be able to override interlocks?
Use MOTCON test function? (how?)
When doing lockout on a motor, locking the safetyswitch off, we need to do a start from the faceplate to check for remaining energy.
If MOTCON is interlocked, what is the best practice to check for remaning energy?
Give all operators permanent tune permission to be able to override interlocks?
Use MOTCON test function? (how?)
Asked 3 months ago
Answers
0
For the AC450 part, its usually easier and much more reliable to select the Digital Output Command Channel and turn that on. For the AC800M part it depends on the process library you use - You say MOTCON so are you using the Pulp & paper Lib ? You may or may not be able to open a faceplate for the Output Command. Unfortunately, the P&P lib is not really designed for this use case.
You should not give operators tune permissions. These will be misused to override interlocks during plant operation and some smart guy is going to think changing all your PID settings at 3 am is a ~ good idea ~
Generally, - Use a Supervisor account that can block interlocks and use Operator Logover with Audit Trail to track who does what. Of course then you get into the problem of interlocks being removed for testing and not returned for operation. And what about interlocks that can't be blocked.
In any case, whatever you decide to do needs to be part of your safety review. If your LOTO procedure is relying on the face plates to test IO channels without considering Software Interlocks preventing the channel from operating then you have a gap.
You should not give operators tune permissions. These will be misused to override interlocks during plant operation and some smart guy is going to think changing all your PID settings at 3 am is a ~ good idea ~
Generally, - Use a Supervisor account that can block interlocks and use Operator Logover with Audit Trail to track who does what. Of course then you get into the problem of interlocks being removed for testing and not returned for operation. And what about interlocks that can't be blocked.
In any case, whatever you decide to do needs to be part of your safety review. If your LOTO procedure is relying on the face plates to test IO channels without considering Software Interlocks preventing the channel from operating then you have a gap.
Answered 3 months ago
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