1771-OFE analog module on ControlLogix system ...

[Ron Beaufort]

Greetings to all ...



I got this in my emails today from somebody new ... I’m answering it here to benefit the forum ... I’ve cleaned out everything that I think MIGHT be “secret” or anything along those lines ...

Hi Ron



Going through some posting you have entered on PLCTALK, you seem rather knowledgeable on the matter.



Attached is a screen shot of the hardware setup of a PLC – Control Logix 5555. On installing the card (1771-OFE2 B) in the remote rack using DH+, the Controller tags inserted do not include any Configuration registers. How do I go about setting up this card using a Message call? The Modbus card inserted in the slot before the analogue output is functioning correctly.



Regards,

________

first things first ... you’re NOT using “DH+” for this ... instead you’re using RIO (Remote I/O) ... blue hose - YES ... Data Highway - NO ...



next ... in most cases you’ll need to consult the User Manual for your specific Analog Card in order to come up with the proper “bit pattern” data to be sent to the card ... or ... if you’re blessed like I am, you have a spare PLC-5 and RSLogix5 software standing by ... so you run the configuration through that system - and then copy the data over into the “latest and greatest” ControlLogix and RSLogix5000 platform ... as you’ve noticed, RSLogix5000 doesn’t include the capability to help configure this “oldie-but-goodie” 1771 stuff ...



the notes below should get you going ... if you have specific questions you may CALL me ... if you email, I’ll eventually get a chance to answer, but it will probably be several days ... lately I have more time to talk than I have time (and energy) to type ...



or ... better yet, post your future questions on the forum ... there are many members here who are qualified to help you ... and questions asked on the forum benefit everybody ...

you didn't mention any details about how you want your module to be configured (scaling, etc.) - so I went with the “plain vanilla” settings that I use in my classes ... this is the way MOST systems in the field are set up ... your mileage may vary ...

hope this helps ...

 

[daba]

Ah, this takes me back, Ron. Well not that far actually, less than 2 years ago I worked on several system upgrades where the existing 1771 I/O was retained, while the controllers were upgraded to ControlLogix. ASB's replaced PLC5's

I used exactly the methods you described to get the binary data I needed to load into the 1771 configuration BTR tag data. Although I was lucky it already existed in the PLC5 backup files.

A well-presented explanation, and well worth a bump.


And I can also recall, some years before, a junior programmer spent hours with the manual, poring over all the module configuration data bits, bytes, nibbles, etc. determining the correct bit patterns, converting to data values, and storing them in the configuration BTR files for N-series analog cards.

And then he started to read the next chapter in the manual....


(for those who don't know - the next chapter introduced the "Configuration Utility", built into the 6200 software, which did all the bit and byte pattern encoding for you).


The well-used acronym "RFM", "Read the Fxxxxxx Manual", I always thought was a derivation from "RMF", "Read the Manual First".

 

[Ron Beaufort]

Greetings daba ...



and thank you for the kind compliments ...

And I can also recall, some years before, a junior programmer spent hours with the manual, poring over all the module configuration data bits, bytes, nibbles, etc. determining the correct bit patterns, converting to data values, and storing them in the configuration BTR files for N-series analog cards.



And then he started to read the next chapter in the manual....



(for those who don't know - the next chapter introduced the "Configuration Utility", built into the 6200 software, which did all the bit and byte pattern encoding for you).

and I thought that I was the only one who ever did that ... that was EXACTLY how I learned to configure analog modules many years ago ... I labored for DAYS through the manual for the module - and finally got the thing to work ... and THEN later I found out that the software would generate the configuration bit patterns for me ...



the "silver lining" is that I learned how each and every one of those bits affects the system's operation ... so far I haven't ever NEEDED that information - but who knows what tomorrow will bring ...



somewhat along these same lines of using a PLC-5 system as a "tool" for a ControlLogix setup, here is something else that comes to mind ...



the PLC-5 will do a handy "Autoconfigure" of a Remote I/O network - something that the newer SLC-500 and the ControlLogix systems can't do ... so ... anytime I'm working with an SLC or CLX and I have trouble with a RIO system, one of the first things that I do is fire up a spare PLC-5 and let it investigate the network for me ... it quickly shows the addresses and the rack sizes of the various devices that are currently communicating ...

the only way to get that sort of information otherwise is to dig through the manuals for all of the remote devices - and nuke out the DIP switch settings, etc. ...



secret handshake: when switching the "blue hose" network connection between the RIO port on a PLC-5 and the RIO port on a 1747-SN module (for an SLC-500 system) the positions of the CLEAR and the BLUE conductors must be physically SWAPPED ... note that the 1756-DHRIO module for ControlLogix uses the same alignment as the PLC-5 ...