Eurotherm 2408i

Subject to there being enough voltage to drive the loop, Mate, just string 'em all in series. That way the current in the loop will be everywhere.

Shame really, as I do a good line in secondhand previously-enjoyed power supplies as a sideline from my supplier in Vange. There'a one or two in my skip going begging <wheeze, cough>.

For calibrating, refer to section 4.5.2 of the engineering manual. You'll need to select sensor type mA, and set up the offset (to allow for the 4mA zero point), and set the span for readout = 90 with the silo full.

It's not obvious from the docs, but I'd guess you go with Stinky, & just connect across the V- and V+ sensor terminals.

I have several of the Eurotherm 2408i controllers in use. You my buy a 24 VDC power supply module that goes in Module 1 position ( TRANSMITTER PSU AHO25863 ), or you may use an external power supply. I have had problems when I powered more that 10 units from the same external power supply.

You must also place a 2.49 ohm precision resistor across terminal V+ and V-. This is the sense resistor for the 4 - 20 mA current.

Best of Luck, Mike

Further to other comments - I suggest you call Eurotherm & ask for technical advice.

If they supply crap manuals, they should sort it out.