PLC5 && 1771-IFE Questions

[Wormfood]

I have a PLC5 5/15 that use to read a level probe (4-30mA) signal from a 1771-IFE analog input card. The probe has been out of use for probably 10 years (if not more). I'm trying to reclaim the life of the AI card, but can not seem to get anything to read on the input side. Now trying to read a 4-20mA signal for IR thermocouple.

I think the configuration is right for the BTR & BTW instructions, but I'm going by the I/O configuration in the PLC. The rack is actually 7-slot rack with all the I/O in the rack. Not worried about the previous configuration (like I said, the other device died, and was never replaced).

I've done similar instruction moves with the Generic Block Transfer as the Module Type and BT registers as the Control Block, never as that 1771-IFE analog card and an integer file as the control block. Pretty sure that I have the data file set up properly (although the max scaling is a question).

I've attached the PLC I/O configuration that I found, and a shot of the PLC ladder (PLC5.JPG) that is being used. I'll attach a picture of the rack on the next post. Does anyone see my issue?

 

[Wormfood]

Picture of my rack. The wiring has changed on the analog. This pic shows to analog. I removed the first analog input (since the device no longer works) and wired my IR sensor to the same place. Reading 5.6mA on the IR sensor input, but the value never gets into the PLC.

 

[Ken Roach]

The first thing that I see is that the sizes of the Block Transfers are incorrect.

The BTR for a 1771-IFE should be 20 words long; you have 5.
The BTW for a 1771-IFE should be 37 words long; you have 7.

I'll bet the BTR's error indicates it's the wrong request size. The 5 words you have are status and overrange/undderrange; the input data begins on Word 6.

Did the BTR/BTW wizard create the instructions and the I/O data files automatically ?

Is the 1771-IFE actually in the first slot of Rack 01 ? What addressing mode (half, 1-slot, 2-slot) is the Rack set up for ? What's in the second slot ?

 

[Ron Beaufort]

your screen shots aren't readable - and least to my poor tired eyes ...

can you post your entire RSP program file? ... you'll need to ZIP it first ...

also - have you checked the IFE card's internal jumper settings? ...

 

[Ken Roach]

Nice photo !

OK, so the BTR/BTW are also directed to the incorrect slot number. That's a 1771-A3B chassis with 12 slots, and there are adjacent 16-bit input modules, which suggests you're using "Single Slot" addressing (I might be wrong about that; only the backplane switches will tell us for sure).

The first 8 slots of this Chassis are Rack 00. The second 4 slots of the Chassis are Rack 01, Groups 00, 01, 02, 03.

So, the 1771-IFE is in "Rack 01, Group 02, Slot 00."

 

[Wormfood]

Ok, attached is the PLC code.

Found the following issues:
#1 - PLC communiation was overwriting my data file.
#2 - Fixed Rack Group Error as pointed out in the above posts.


Still tryinh to reading only 1 word. That status shows that the work s over ranged.

I'm pulling the card tomorrow and checking jumper settings for differential/single ended inputs (original is wired differential, but the meter doesn't allow mA signal to flow through meter in series.)

Can read 5.6mA at the card, nothing comes in the PLc

 

[Wormfood]

PLC code....silly thing won't attach as *.rsp, so zipped as recommended (Maybe I'll learn to read!)