Analogue Input scaling in a S5 CPU942b

MartinW

Member
Join Date
Apr 2008
Location
UK
Posts
70
Hi all you gurus,

I've got a CPU942b which is reading an analogue input, and scaling it, but I'm getting odd results.

In short, what the code is doing is (I'm shorthanding it because it uses lots of DO instructions)

L PW128
SLW 1
SRW 4
T FW218

Now to my simply brain, this means that the resulting value in FW218 should be scaled 0-10V = 0-2048

However when I monitor FW218 it shows a value of 2812

The only other places that FW218 is used are for read/comparison.

What would happen if, say, I had 13V instead of 10V going to the analogue input card. Would it discard the "extra" 3v or would it read 21294 instead of 16384?

Thanks

Martin
 
The answer is that the input was indeed receiving 13V. It wasn't supposed to; it's fed with a 10V supply.....but that's another story.

Thanks all.

Martin
 

Similar Topics

Hello guys I am just wondering do I need to set up each channel configuration, including enabling the channel , ranging … if I have already...
Replies
8
Views
1,975
There have been a number of posts asking about scaling so I thought this may help. The formula is: Out := ((Variable_In - ZeroIn) / (SpanIn -...
Replies
11
Views
5,985
Hi, In a Siemens, when you read an analogue input from a standard modul you read in the range 0-27648 INT value. What is the range in a TSX...
Replies
1
Views
1,637
Hi, I have a device which is giving out a 4 -20mA signal but the ADC's on the PLC channel do not match. The supplier is saying the channel needs...
Replies
2
Views
736
Hi, I'm planning to install a new Analogue Input module Q68AD-G. It will inserted on Rack 0 Slot 4. When it's installed, will the code recognise...
Replies
6
Views
2,406
Back
Top Bottom