How can I clear a RS5000 UDT in Stuctured Text?

[PLC_Shaggy]

I'm using RSLogix 5000 v20. I have created a User Defined Type that I would like to zero out in Structured Text.

In Ladder I can use the FLL command

FLL(0,myUDT,1)​

This works great. But the FLL command is not available in ST. So at the moment I am setting each item individually.

 

[bernie_carlton]

Even in ladder I create and maintain an empty UDT based tag. Then I just COPy that into the target UDT.

 

[dbh6]

Well depending on what your udt is can't you just initialize the udt by using the assignment operator Ex. UDT tag := 0? Or I remember in ladder for logix 5000 their is a CLR instruction which I think clears the bits which also gives you a value of 0 not sure if that is available in ST but you can check.

 

[PLC_Shaggy]

Thanks Bernie the COP command did work.

COP(nullUDT,myUDT,1);​

I also tried these two methods, but neither worked:

• myUDT:=nullUDT;
• myUDT:=0;

CLR is not available in ST, but even in ladder it does not work with a UDT.

 

[jstolaruk]

To clear the the members of a udt, you'll have to address each one individually.

Myudt.a := 0;
Myudt.b := 0.0;
etc.