1771 OFE BTW clarification

Hello,

I am having issues getting my channel output voltages to change (1-5vdc) by manipulating the data file values. I am also curious as to my scale max. It is an existing PLC5/20e program that has unused analog outputs for some time that are now trying to be utilized for something different.

My data file block for BTW is N16:111 Length 37. So I am changing values in registrs N16:11,12,13,14 respectively for 4 output channels.

My understanding is the max scale for all votage/current outputs is 4095. My register scaling starting at bit N16:117 is 16533. I am confused by this, and is this possibly causing my issues?

Right now I have 2.8vdc on channel 0, 1vdc on channel 1, 1vdc on channel 2 and 3.5vdc on channel 3.

My values for N16:111-N16:114 are 0,0,1280,16533.

I've done this before in a previous program and everything worked fine and matched how the manual for the module explains it.

I'm missing something on this application. The rung has also been disabled some time ago by a timer that would never execute. I am testing with a test toggle bit.

Any insight/explanation for the pros would be really appreciated.

Thanks,

B

short on time - but here is something that jumps out at me ...

My data file block for BTW is N16:111 Length 37.

Click to expand...

the length 37 in a BTW is USUALLY set up to configure an analog INPUT module (for example: a 1771-IFE) ... make sure that you're working with the correct BTW ...

the length of a BTW for an analog OUTPUT module is USUALLY about 13 ...

going further ...

if you're allowed to do it, you might consider attaching your ENTIRE project file (.RSP extension) and we'll try to help you with some more detailed answers ... you'll have to ZIP the file first (forum rule) before you can attach it to this thread ... note that some of us here will not access a file from a dropbox, etc. due to security reasons ...

hope this helps ... good luck with your project ...

Ron beat me to it...

for a 1771-OFE, the BTW length should be 13 maximum.

Scaling maximum should be 9999

What value is the configuration word? prob N16:115

I like the documentation provided with the PLC5 for analog cards (setup screen in the BTW instruction) as it gives a clear user interface to the configuration and scaling. Do you know if that has been done for this module?

Program attached

Rung 107 is the BTW for my output (I think). My 1771 OFE is physically in slot 5 of local chassis.

JohnCalderwood said:

Ron beat me to it...

for a 1771-OFE, the BTW length should be 13 maximum.

Scaling maximum should be 9999

What value is the configuration word? prob N16:115

I like the documentation provided with the PLC5 for analog cards (setup screen in the BTW instruction) as it gives a clear user interface to the configuration and scaling. Do you know if that has been done for this module?

Click to expand...

***I get no modules exist error on setup screen***

To add this module to the documentation:

Goto <controller> <IO Configuration>
Double click on <chassis type> and change it to the correct size (no of slots)
Then add the 1771-OFE module to slot 4 (rung 104 and 105)
It will then prompt you for the BTW and BTR parameters.
Put them in and it should show you the I/O Screen.
(see attached capture)

I would change the BTW length to 13 and the BTR length to 5.
Then change the data format to binary and set the voltage ranges to the ones you need....check the jumpers are correct on the module

Tell us what happens then....