Hello everyone,
I am working with a Logix5561 processor. I have a program which was written for SLC 5/04 PLC which used a lot of ONS (Ons Shot) instructions. We did an automatic port of the SLC 5/04 program to the ControlLogix platform. In SLC 5/04, the ONS instruction is left untouced at power on, i.e. all the ONS instructions are cleared. In Controllogix, the ONS instruction is SET during Prescan. The old SLC 5/04 program relied on the fact that 5/04 DID NOT SET the ONS during prescan because it caught alarms based on this fact on power up.
My question is: Is there a way to change this default behavior inside the ControlLogix PLC? I was trying to write code in the Power-Up Handler to clear the ONS instructions so that the Logix5561 can pickup alarms during the First Scan. I am not having a lot of success with it.
Please help.
With best regards,
bobby1234
I am working with a Logix5561 processor. I have a program which was written for SLC 5/04 PLC which used a lot of ONS (Ons Shot) instructions. We did an automatic port of the SLC 5/04 program to the ControlLogix platform. In SLC 5/04, the ONS instruction is left untouced at power on, i.e. all the ONS instructions are cleared. In Controllogix, the ONS instruction is SET during Prescan. The old SLC 5/04 program relied on the fact that 5/04 DID NOT SET the ONS during prescan because it caught alarms based on this fact on power up.
My question is: Is there a way to change this default behavior inside the ControlLogix PLC? I was trying to write code in the Power-Up Handler to clear the ONS instructions so that the Logix5561 can pickup alarms during the First Scan. I am not having a lot of success with it.
Please help.
With best regards,
bobby1234