Hi, I have a 1762-OF4 A/O Module connected to my ML 1400. The module is configured through RSLogix 500 and wired properly per the UM. The problem I have is that I do not know how to enter the scale values to get 4-20mA from the module. Can anyone please show me step by step what function do I need to set this it up? I need to be able to select 8mA, 12mA, 16mA & 20mA. Where should these values be stored? Please provide a link or screenshot on how this should be done. Thank you in advance.
ML 1400 & 1762-OF4 Operation
- Thread starter caleno
- Start date
This forum thread should help.
http://www.plctalk.net/qanda/showthread.php?t=33024
http://www.plctalk.net/qanda/showthread.php?t=33024
Mickey
Lifetime Supporting Member
Writing to the module's output word, depends on where it is located. (slot # ??)
If you can tell us that or post the .RSS file ( zip it first) someone can tell from that.
The above raw data written to the card will depend on how you have configured it
"Raw Proportional" or "Scaled for PID"
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Guys Thank you so much for the help. I actually used the info at the thread below. It shows exactly what I needed to know. Now I am using the SCP instruction for my 1762-OF4 and it is working fine.
The problem I have now, is that I am also using a 1762sc-OF8 module. It is properly configured and working with the PLC and RSLogix 500. The problem I have here is the scaling again. Shouldn't the scaling used for my 1762-OF4 work for this module as well? I tried to use it, except that I changed the Output from O:2.0 (1762-OF4) to O:1.0 (1762sc-OF8). the mA value I get is different on both modules. Shouldn't one scaling work for both modules?
http://www.plctalk.net/qanda/showthread.php?t=36263
The problem I have now, is that I am also using a 1762sc-OF8 module. It is properly configured and working with the PLC and RSLogix 500. The problem I have here is the scaling again. Shouldn't the scaling used for my 1762-OF4 work for this module as well? I tried to use it, except that I changed the Output from O:2.0 (1762-OF4) to O:1.0 (1762sc-OF8). the mA value I get is different on both modules. Shouldn't one scaling work for both modules?
http://www.plctalk.net/qanda/showthread.php?t=36263
Mickey
Lifetime Supporting Member
It depends on how you have it configured. Raw values are very different. See pdf
And link to the manual if you don't have it.
http://www.spectrumcontrols.com/products/1762-micrologix/1762sc-of8/
And link to the manual if you don't have it.
http://www.spectrumcontrols.com/products/1762-micrologix/1762sc-of8/
Mickey, attached is a screenshot of the SCP instruction I am using with the 1762-OF4. N7:4 carries the value that changes the output mA value. Currently it has 20015, which gives me 20mA reading. So
20015 = 20mA
17000 = 16mA
14000 = 12mA
11000 = 8mA.
Now that I am using the scale above. How can I use it or modify it to work with the 1762sc-OF8 to obtain the same mA output reading on both modules?
Thank you
20015 = 20mA
17000 = 16mA
14000 = 12mA
11000 = 8mA.
Now that I am using the scale above. How can I use it or modify it to work with the 1762sc-OF8 to obtain the same mA output reading on both modules?
Thank you
Mickey
Lifetime Supporting Member
Why are you using an "SCP" instruction?
I don't understand the 8000 to 20000 range numbers.
Where does N7:4 get it's values from?
I don't understand the 8000 to 20000 range numbers.
Where does N7:4 get it's values from?
Mickey
Lifetime Supporting Member
Is the 1762-OF8 configured for "Raw Proportional"?
If so a "MOV" instruction is all you need
Source N7:4 (value 31176 = 20ma)
Destination O:2.0
A "MOV" instruction is all you need for the 1762-OF4 also
Source N7:4 ( value 31206 = 20ma
Destination O:2.0
If so a "MOV" instruction is all you need
Source N7:4 (value 31176 = 20ma)
Destination O:2.0
A "MOV" instruction is all you need for the 1762-OF4 also
Source N7:4 ( value 31206 = 20ma
Destination O:2.0
I got the SCP instruction from this link and it worked.
http://www.plctalk.net/qanda/showthread.php?t=36263
N7:4 values' are pre-programmed. I chose those values cause they gave me the 4, 8, 12, 16 & 20 mA.
Please indicate if I should use a different way. thanks.
Mickey
Lifetime Supporting Member
See my last post above. (you posted as I was typing, with one finger)
Mickey
Lifetime Supporting Member
Do you have both cards installed?
If so then the output word address will be different of course.
If so then the output word address will be different of course.
Mickey
Lifetime Supporting Member
Now if you are using N7:4 to hold the ma value then the SCP instruction will work for you.
Input min 4 (4000 would also work ,suit yourself)
Input max 20 (20000 would also work, suit yourself)
Scaled min 6241
Scaled max 31206
Input min 4 (4000 would also work ,suit yourself)
Input max 20 (20000 would also work, suit yourself)
Scaled min 6241
Scaled max 31206
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