4 20mA signal

[deekay999]

Can I parallel a 4-20mA signal from a transmitter to a PLC input and another device such as a display?

Assuming both are compatible for a 4-20 signal

 

[electrageek]

Yes but you don't need to parallel them you need to series them. Go out of one and into the other and return to the common side of the transmitter.

If you had a voltage input device you could convert the 4-20ma into a voltage by placing a 250 ohm resistor in series with the 4-20ma. The voltage drop across the resistor will be 1 to 5 Vdc. Quite a few devices actually work by first converting the 4-20ma into a voltage through the use of a dropping resistor.

 

[buzzp]

Depends on if they are loop powered or not.

 

[buzzp]

electrageek is correct also. YOu need to series them, not parallel. Parallel would split the current in half to each device assuming both have equal resistance.

 

[deekay999]

Thanks guys.

My first thought was also the loop powered issue.

If they are not loop powered is series still the answer?

Thanks

 

[Macbeth]

If they are loop powerd it lies in the power suply voltage.
Most devices need at least 11vdc to operate. Don't forget in a series ckt the sum of the voltage drops is equal to the sorce. Increasing the supply voltage should take care of any problems.