Convert SINT to DINT

[luffy 0]

Hi guys 

I am still learning my ways around Allen Bradley plc. So at the moment I am in need of a solution ASAP.

One of the PLC is currently sending values in SINT data type and on the other PLC I have to convert the SINT data type to DINT data type. The 1st plc is sending values in a SINT data type and the second one should read those values in a DINT data type. 

So I am currently struggling with the conversion of the two data type. I want to convert SINT to DINT. 

I would really appreciate your response. Thank you in advance 

[pturmel 160]

You can't convert in the message. One processor or the other needs to make another tag, matching the datatype in the other.  Then the message will work tag to tag.  The value can be converted in the one processor by simple assignment (ladder logic MOV instruction).

[luffy 0]

@Sparky thank you for your response. If I may, can you please send an example of how the ladder logic should look like.

I do understand what you're saying, so I am trying to figure how will ladder logic look like. I would really appreciate it and I hope I'm not taking a lot of your time. 

[pturmel 160]

Dev tool not handy over the weekend, but the code is just one instruction "MOV someSINTtag someDINTtag".  Allen-Bradley processors automatically convert datatypes when moving or assigning into a different type.

[luffy 0]

Alright, Thank you for the information. I will give a try tomorrow. 

I really appreciate it.

[dumdum 1]

Keep in mind when using mov, -1 sint value (all 8 bits = 1)  moved to dint would be all 32 bits = 1.

[pturmel 160]

Yes, Allen-Bradley integers (at least up to recent firmwares) are signed.  Moving to a larger register size performs sign extension.  This is all documented in the instruction set manual.  The simplest way to avoid that would be to use AND instead of MOV.