Ran into a really crazy one tonight. A 1771-OFE2 /B card which was controlling a modulating valve stopped working.

It was in Rack 21 Slot 2 in the old PLC 5 nomenclature but now connected to a 1756-L653 through a 1756-DHRIO to a 1771-ASB. and BTW Message.

The Valve in question was on Ch1 and could be controlled by a Fluke 787 Processmeter when the wires were moved from the swing arm to it.

The 13 BTW Words had the following data when I found it.

Word 1 = 4095
Word 2 = 0
Word 3 = 587
Word 4 = 0
Word 5 = 0
Word 6 = 0
Word 7 = 100
Word 8 = 0
Word 9 = 100
Word 10 = 0
Word 11 = 100
Word 12 = 0
Word 13 = 100

The BTR Status Bits were as follows.
.0 = 1
.1 = 0
.2 = 1
.3 = 0

After reading the manual I tried changing the Max Scaling so the config was as follows
Word 1 = 4095
Word 2 = 0
Word 3 = 587
Word 4 = 0
Word 5 = 0
Word 6 = 0
Word 7 = 4095
Word 8 = 0
Word 9 = 4095
Word 10 = 0
Word 11 = 4095
Word 12 = 0
Word 13 = 4095

The resultant Status bits was:
.0 = 1
.1 = 1
.2 = 1
.3 = 1

Went Back and adjusted the ch1 data requested as follows:
Word 1 = 100
Word 2 = 0
Word 3 = 587
Word 4 = 0
Word 5 = 0
Word 6 = 0
Word 7 = 100
Word 8 = 0
Word 9 = 100
Word 10 = 0
Word 11 = 100
Word 12 = 0
Word 13 = 100

And the Status Feedback went to the following:
.0 = 0
.1 = 0
.2 = 1
.3 = 0

And the valve started working.

Wrote this all up for Elec. Eng. to review in the AM, but wonder why I could change the max scale to 4095. Manual says I should be able to.

Bigger question is I don't know how or who broke this. Problem originally showed up at 11am and I inherited it at 3pm.

OH the joys of covering 2nd shift!

Is there some scaling that was set on the card?

The BTR Status Bits were as follows.
.0 = 1 enable
.1 = 0 enable waiting
.2 = 1 start
.3 = 0 done

is this correct? Found it on the help file

The BTR Status Bits were as follows.
.0 = 1
.1 = 0
.2 = 1
.3 = 0
above
this is saying it was enabled and started but did not transfer info to its destination target address.


The resultant Status bits was:
.0 = 1
.1 = 1
.2 = 1
.3 = 1
above
This looks like it just puked and in an unknown state.

And the Status Feedback went to the following:
.0 = 0
.1 = 0
.2 = 1
.3 = 0
above
start transferring the data but why is not the done bit set?
Maybe as in all program logic its done and then gets reset i am sure.
Just do this count the dn bits as a test to see if the BTW is working. Put an add instruction in to count the dn bits or .3 bit.

Your question? I think your venting for being on second shift. hehe

When I said Status Bits I meant the status of the 1771-OFE2 not the status of the BTR.

THe BTR brings back 5 Dints
DINT 1 = DAC 1
DINT 2 = DAC 2
DINT 3 = DAC 3
DINT 4 = DAC 4
DINT 5 = Status Bits

and
DINT 5.0 = Fault Channel 1
DINT 5.1 = Fault Channel 2
DINT 5.2 = Fault Channel 3
DINT 5.3 = Fault Channel 4

Is there a MSG that sets up the configuration of the card?

I have seen the 1771-OFE lose its configuration before and exhibit similar symptoms. Our were set up to only write the configuration on first scan. We changed them to read the configuration and trigger the BTW when there was a mismatch between what we read and what we wanted. This was on a PLC5 controlled system by the way.

Paul

error bit set for that channel is just saying you sent an invalid channel data is being sent to the analog card

Why is channel 2 still showing error when everything is good?

Has to be a scaling issue inside the card?

Maybe the scaling is set in a data table and became corrupted during either power glitch, lightening strike, or whatever caused the memory to become corrupted during this moment.

Might be good idea to hard code the parameter at first scan like Paul was pointing out to you.

Issue resolved by our EE today.

Turns out to scale a 1771-OFE2/B from 0 to 4095 you need to select binary data format not bcd.

In other words BTW Data word 5 bit 15 needs to be a 1 not a 0.

No one is sure how the card config got so "hosed" but it is working now with 0 to 4095 scaling as we all are used to.

There was a contractor on site and connected to the PLC yesterday morning, but I'm in a "glasshouse" so I'll reserve judgement.

BCD - that keeps coming up

see attached file from pdf
When you say bit 15 needs a 1, are you talking about the decimal bit 15?
I was just looking at the manual and that bit is not used.
If you talking about bit 15 octal that is part of reserved part of the word 5
maybe decimal bit 14 in word 5?
manuals sometimes are confusing to me.

Dude - what you posted is the BTR Data Word Description I am referring to Word 5 bit 15 decimal or bit 17 octal of the BTW Data Packet that goes out to the card.

Look back a chapter in the manual you'll find the 13 word BTW Packet description and it should make sense.