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Old September 6th, 2005, 07:27 AM   #1
Keldog
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Talking Scaling

I'm fairly new to Control Logix 5000 and i was wondering if there is anyway to change the scaling on an Analog I/O card? It's already installed and i would like to change some of the values that are set already.
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Old September 6th, 2005, 07:50 AM   #2
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You can change the scaling either online in the hardware (I/O) config... Right click on a module and select properties.

You can also change the module scaling values programmatically by messaging to the module. You will need to refer to the analog modules manual for the details.
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Old September 6th, 2005, 09:12 AM   #3
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thanks rdast, but i'm not having much luck getting it changed i can change it in the program but the second i accept the change it goes back to the original number..
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Old September 6th, 2005, 12:17 PM   #4
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Make the changes offline and then download the program again - the new I/O configuration should then work.
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Old September 6th, 2005, 01:52 PM   #5
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is there a way to do it without uploading the program again. If i stop the program everything is going to come to a screeching halt and then i'm in trouble...
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Old September 6th, 2005, 02:09 PM   #6
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Not that I know of. As far as I'm aware (please correct me if you know better), you have to make the changes offline as you are essentially re-writing the I/O configuration, which obviously you have to download to the processor each time you make a change.
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Old September 6th, 2005, 02:14 PM   #7
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no your right, i didn't think you could, but i was just hoping somebody knew a shortcut. It's gonna suck to have to shut everything down but thanks for your input.
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Old September 6th, 2005, 02:18 PM   #8
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wonder if i could create a bit to make the BTR shut off while i change the value then turn it back on and it should read the new value into the BTW.... (i could be wrong though)
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Old September 6th, 2005, 02:22 PM   #9
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It might work, but I doubt it. Configuration changes usually mean shutting down the processor so it can upload the new values when it restarts.
If you do find a way please post it on here for all to see, good luck.
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Old September 6th, 2005, 02:24 PM   #10
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thanks man, i'll let you know if i find away around it
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Old September 6th, 2005, 03:17 PM   #11
Ron Beaufort
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failure to communicate? ...

Greetings Keldog,



something sounds kind of fishy here ... what type of analog modules are you using with this ControlLogix system? ... your mention of BTWs and BTRs makes it sound like you might be using 1771-type I/O ... maybe in a remote rack? ... maybe if you tell us exactly what you have - and exactly how you want to change it - then maybe we can come up with a reasonable workaround ...



one thing to consider: how about just adding in some temporary math functions (on extra rungs) to have the processor do the “new” scaling for the time being? ... you shouldn’t have to shut anything down to take care of that ... then the next time your plant has a down-day, you could download the new scaling to the module and delete the temporary fix ...



but ... if you really are using 1771-type I/O (with BTWs and BTRs) then there’s a good chance that you can “reconfigure” the modules without shutting down the system ...



best course of action: post your code ...
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Old September 6th, 2005, 04:08 PM   #12
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1756 Series and other modules that run on BTR/BTW (Flex, 1771, etc) allow for reconfiguration on the fly.

For 1756, you make the changes for each channel on the scaling or channel tab on the module properties box (while online), and hit apply. You will get a warning that the MODULE may (or will) go offline while the changes are applied, but this really shouldn't hurt anything (unless you are making major changes that will confuse your process).

Programmatically configuring 1756 modules is a bit more complicated, and requires the use of CIP formatted MSG instructions with specific attributes, but works fine.

If you really do have a BTR/BTW module, it's likely that the program is constantly writing a default set of values to the module, so if you try to make a change, it gets tossed away. If that's the case, find the data for the associated BTW, and write the scaling values in there.
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Old September 6th, 2005, 06:07 PM   #13
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The 1756 modules should be able to be reconfigured online. I just tested it with an unused channel on one of our CLXs and had no problem changing the scaling.

I concur with Ron and rdrast - you might have some code that is writing the configuration back to the module programatically.

IIRC, there was a tech note about excessive messaging to the IO modules and the flash memory on the modules, so if the program is already overwriting the configuraiton when its not necessary you may want to change that anyways. I could be wrong about the tech note, it may have been about messaging to another device, but at any rate, its not necessary to constantly write a module's configuration across the backplane.
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Old September 7th, 2005, 06:14 AM   #14
Keldog
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Ron is totally correct it is a 1771-I/O module in a remote rack.

message1read.en message1write.en |--------MSG------|
|------|/|-----------------|/|---------------| BTR |
| Message1read |
|-----------------|
message1read.dn message1readfal
|------|/|-----------------(res)-------------|--------FAL------|
|Message1readFAL |
| |
|-----------------|
message1write.en S:FS message1writefal
|------|/|-------------| |------(res)--------|--------FAL------|
|Message1writeFAL |
| |
|-----------------|
message1writefal.dn
|--------| |---------------------------------|--------MSG------|
| BTW |
| Message1write |
|-----------------|

I'm sorry if that is confusing to anyone but i just took over this program not long the guy who originally wrote the program is gone now so i'm still trying to figure out how it is ran. When i look at the tags it's all set up but if i try to change the number it won't keep. So hopefully this clears stuff up for someone if they were wondering what i meant. sorry about the confusion.
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Old September 7th, 2005, 06:15 AM   #15
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Sorry i just started using this forum the rungs are a little messed up but just move them second and third rows in each rung over to the FAL instruction and it should make more sense
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