How do I create a tag for First scan when using RSlogix5K to program a 1769L30 compact logix.
In the help a see a tag "s.fs" but how do I create this tag ?
Thanks

Message text:

 

The logix platform lets you create an entire program that will execute one scan on power up. In your nav tree, right click on the Power-Up Handler and pick new program.

To access s.fs you can use the GSV (Get System Variable) instruction, but the Power-Up handler is a better way.

 

There is already a system tag for that, no need to create one. Use s:fs

grs

 

I found s:fs quite by accident. I wanted the first scan bit, so I typed, "S:1/15" and the software changed it to s:fs. Do you know how I find out about other system tags I might like to use?

 

Thanks Guys s:fs is what I was looking for.

Why will the following give a major error when in the power up handler but not when in the main program
MOV 2#1000_0011_000_0100 AI_CONFIG_VALUE

Where Ai_config_value in the configuration word for a 1769 IF4 analog input card.

Thanks again

 

The RSLogix help topic "Access Runtime Controller
Configuration and Status" describes the following:

S:FS First Scan flag
S:N Negative flag
S:Z Zero flag
S:V Overflow flag
S:C Carry flag
S:MINOR Minor Fault flag

Any other processor information must be obtained by using the GSV (get system variable) instruction.

Anthony Kerstens P.Eng.

 

Watch out - the Power-Up Handler does not execute on every first scan. Only if the controller had lost power while in RUN mode and is powering up again without the key being switched to Program.

 

> There is already a system tag for that, no need to create one. Use s:fs

Can I just type in S:FS, as i cant see it in the drop down menu to select it?