How to compare 2 identical scanned values in Micrologix 1400 PLC

[asjeetabhi8816 0]

I want to compare 2 identical scanned values in Allen Bradley Micrologix 1400 PLC. What are the instructions required to do that?

[Armadillo852 25]

Depends what you want to do.

EQU: If the values are equal to each other.

NEQ: If the values are not equal to each other

GRT" If A is greater than B

GEQ: If A is equal to or greater then B

LES: If A is Less than B

LEQ: If A is equal to or less then B

[b_carlton 61]

If by 'scanned values' you mean strings then use the ASR command.

[kaiser_will 65]

Please clarify...what do you mean by "scanned values"?  Float, real, string/ASCII?

[asjeetabhi8816 0]

Its a string.

and I want to know if i scan a certain barcode,then can i store or use that barcode to match the exact same barcode which i will scan later?

 

 

[b_carlton 61]

You can use COP (Copy File) to copy one string to another. Later, as mentioned, you can use the ASR command to compare strings.

[asjeetabhi8816 0]

Thanks for the reply b_carlton

But how to use this copy command in case of string?

I have put ST12:1 to source and ST12:2 to destination with 10 as length.but it is saying my program has errors.

So can you tell me how to put values of string in COP command.

[asjeetabhi8816 0]

I have tried COP command again and this time its working.

But i have one problem, when i scan a certain value at  ST 12:1 (as an example),then the value gets copied to ST 12:20(through COP command).But when i reset the scan and scan again the value do not remain on ST 12:20.It gets vanished.

So can you tell me how to save that value so that i can compare it with another scan

[b_carlton 61]

It sound like your program is continously copying ST12:1 to ST12:20 so that when you 'reset the scan' ST12:1 is cleard and the cleared string is copied. If you can create a PDF printout of your program or at least this particular section we could look at it. (I only have the 'free' software and it can't operate with a Micrologix 1400 program.)