Two Transmitter Connection

Not enough information.
Presumably connect a single power source to both. Afterall you can power two lightbulbs from the same source in your house and I believe some people can even run a TV and a light at the same time

Presumably the power input to the device will have some individual protection and if the devices comply to EMC EMI regulatioins they won't interfere with each other. As long as the power supply is suitably rated there should be no problem.
Del

Use this.

If these are in a 4-20mA current loop, you may be able to series two or more together. It depends on specific transmitter type(s).

Loop powered transmitters can not be connected in series in one loop because it makes no sense. How can one single loop consisting of two transmitters in series represent two different process variables?

A transmitter regulates the current in the loop by varying the loop current to get the loop current to match a proportional representation of the process variable that the transmitter is measuring.

A single loop with a DC current the same in all parts of the loop can't represent more than one process variable.

Connecting loop powered transmitters in parallel to a power supply has been done since the development and commercialisation of electronic transmitters.

4-20mA loop loads, the analog inputs that receive a 4-20mA signal, can sometimes be connected in series, depending on the common mode and isolation characteristics of the devices involved.

I wasn't sure whether two different variables were to be measured, versus multiple devices sharing the same signal for one variable. (Such as a sensor, a PLC, and an additional display.)

If the transmitters in question communicate using HART, you do have the option of building a "multidrop" network where the transmitters no longer output 4-20 mA analog signals but instead communicate only via HART digital messages. HART multidrop is seldom used because it is very slow and often unsupported by control platforms.

easy. Just connect the supply to both loops, Boss.

What we do is to connect the (+) of the transmitters to V+. The (-) is connected to the individual PLC inputs. I encountered only one instance where the devices were connected in parallel.

We were measuring the level of tanks by monitoring their weights. We used two load cells that had outputs of 2...10 mA. Connecting them in parallel made them 4...20mA.

regards,

Vulcan (",)