Analog signal conditioning (1 AOUT to multiple loads)

[wtzll]

Hello,

I am trying to figure out if this is possible.

Say I have one analog output with the following specs:
Output range = 4 to 20 mA
Absolute output load resistance = 500 Ohm or less

One load (it is an analog signal 0-10V on a drive card to control the speed based on supplied voltage) with the following specs:
Input range = 0 to 10V
Input current 1mA at 10V


I essentially need to run 10 loads from one analog output. I know a common way to do that is to use a signal conditioners. Question is will i run into trouble running 10 of these drive cards through a signal conditioner.

I used MCR-FL-C-UI-2UI-DCI before to run 1 load per channel, but that was it.

Conditioner specs:
Maximum output signal per channel = 35 mA or 15 V
Load per channel = ≥10 kOhm at V output

From my calculations 10 loads (in parallel, because voltage drop...) are equal to 1k Ohms load resistance which is not quite 10kOhms required.. Unless I add 9kOhms in series to the load, but will this work?

Thoughts?

 

[osmanmom]

post your diagram sketch

 

[wtzll]

post your diagram sketch

Here you go.

Keep in mind each drive card is getting its own power (24V). I didn't bother to draw that in.

 

[osmanmom]

MCR-FL-C-UI-2UI-DCI base on datasheet are Signal Multiplier

IMO probably it will not work and if it's work it will damage you isolator,

so far i not saw this type of method the max load i know only 2 unit 4-20 MA in series.

i will prefer use small PLC with CPU and analog IO module slot.

others issue how you control the speed with diff diameter/gearbox if exist

 

[dogleg43]

Contact Phoenix Contact or Action Instruments. They have little isolators that have 1 input w/multiple outputs. They are configurable for 4-20mA, 0-10VDC, etc.

 

[osmanmom]

you need test it at workshop

 

[Tom Jenkins]

With a voltage signal this should work, since devices in parallel all see the same voltage. You need to figure the total impedance in each circuit to make sure that you have a load greater than the minimum allowed by the transmitters.

The max output load for the PLC 4-20 mA signal only applies to the total resistance of the signal conditioner. What happens on the output side of it is isolated from the PLC.

 

[osmanmom]

others possibilities

 

[shooter]

You can use the current output if it can run from 0 to 20 mA
This way you convert it from 4 to 0 out.
input is 10 volts, so if you put them all parrallel 10 mA is flowing to the loads, so another 10 mA on 10 Volts need to go to a resistor of 10000 ohms.
If it is possible to set the loads to 2-10 Volt no converter is needed.