Studio 5000 How to get a bit to swap states every scan.

[ezbz]

I want to know how to make a flip flop rung that will change states every scan. This is for a fast sequencer. Is there a special bit similar to a first scan bit that I can use?

 

[JeremyM]

Bit := NOT Bit; ?

Or if the bit is bit zero of a DINT,

Dint := Dint XOR 1; ?

I’m suspicious of this being a troll question.

 

[kalabdel]

Bit := NOT Bit; ?


I’m suspicious of this being a troll question.

No, but there's more to the question, we will eventually find out.

 

[kalabdel]

I want to know how to make a flip flop rung that will change states every scan. This is for a fast sequencer. Is there a special bit similar to a first scan bit that I can use?

Please clarify what you mean with "similar to first scan bit"?
First scan executes only once as the name indicates, on first scan so similar to it would be like........how?

 

[dmroeder]

I'm thinking a counter with it's own CU bit normally closed in front of it. Use the Counters ACC.0 bit, it will toggle 1/0 every other scan.

XIO MyCounter.CU CTU MyCounter 2147483647 0

MyCounter.ACC.0 = odd/even bit, changing state every scan.

Edit: or an unconditional add, adding 1 to itself, same concept with bit 0.

 

[JeremyM]

Please clarify what you mean with "similar to first scan bit"?
First scan executes only once as the name indicates, on first scan so similar to it would be like........how?

He’s referring to just watching a System bit that just alternates continuously, scan by scan.

 

[I_Automation]

XIO BIT OTE BIT


That's how I program a "Every Other Scan" bit for testing and and how I used to count scans per second on SLC's by a counter, then multiply the ACC count by 2.

 

[Ken Roach]

There is no "every other scan" bit built into the ControlLogix operating system.

It is trivial to create one with a single rung or a single structured text statement, simply inverting the value of a Boolean tag.

 

[kalabdel]

What is a fast sequencer?