Allen-Bradley 5069 Analog I/O Modules

Hi all,
I'm hoping to get some advice from you guys who may be familiar with these Allen-Bradley devices. We are using an A-B CompactLogix PLC with 5069 series controller. The 5069 analog I/O modules for use with this controller are 5069-IF8 (differential current/voltage) and 5069-IY4. The IY4 is able to take thermocouple and RTD inputs along with diff current and voltage. The user manual (Compact 5000 I/O Analog Modules User Manual) for both of these modules state that 3-wire analog devices "are not supported regardless of the channel mode configuration." I have a flow meter that is a 3-wire device and its wiring is as shown below:
Flow_Meter_Wiring.png
I am a little confused by the user manual b/c the installation manual for 5069-IY4 (Compact 5000 Analog 4-channel Current/Voltage/RTD/Thermocouple Input Modules) shows the 3-wire wiring diagram below. Couldn't I wire as shown by the single-ended current diagram? The signal wire (Ch) to Input 0+, 24V+ (brown wire) to power supply 24+, my flow meter blue wire to ground, and the power supply 24- to the same common ground.
IY4 Wiring.png

Or for the 5069-IF8 module, couldn't I wire something like this:
1651966045096.png
 

Attachments

I wouldn't worry too much about the 3-wire concept.
1. It's easier to think of design with (using) 2 wires
2. There can, and has been confusion between 3-wire and 4-wire; If you have a Siemens system they generally refer to 2-wire and 4-wire - your own desription above actually has 4 wires - hence the confusion.
You can understand why Rockwell are hesitant is supporting anything above 2-wire.

So your own diagram above is OK - some of us connect -ve to earth, and screen to -ve, but commonsense usually prevails (OK - screen is usually connected panel end only, unless in complete isolation).

You've not mentioned thermocouple directly: these are wired more or less as shown in the manual whether they be 2 or 3-wire.
The odd 4 wire thermocouple -unlike the above take you back to 2 wire, linked to suit.
 
Thanks for the response oneye14. I should have been more clear. Forget the 5069-IY4 AI module. To revise my previous post, I was unclear as to why the 5069-IFA AI module was stating that 3-wire devices are not supported but I see your point. Thanks again!
 
Top