Attachment of One RTD with Two transmitters/ Modules

zia-ur-Rehman, because of the way the circuit converting the RTD resistance change to an electrical analog of the temperature works, your best bet would be to use a temperature measuring device with a repeater output. Eurotherm springs to mind as a company that supply these (see e.g. their model 2408i, discussed recently in another thread).

If the loop resistance is low enough, simply wire the two receiving devices in series in the transmitter milliamp loop.

If it isn't low enough then Lee Dickens (usual disclaimer) does a 1:1 current mirror in its "alphabet block" range.

Dear friend

If you want using one RTD. And you want to connect TWO TRANSMITTER MODULS. YOU DO ONE THING RTD output you directly connect ISOLATOR.It give two output signal then after you connect this signal to two input moduls. This is normally using in redundensy control system

Sir:

I've connected several RTD sensors to one transmitter but never have I found a need to connect one RTD sensor to two transmitters. Understanding why you would want to do this might allow us (or just me ) to help you or provide several alternatives.

If you intend to use one transmitter for alarm and the other for recording, you need not bother getting a second transmitter. Just connect the transmitter output, alarm limit and recorder in series. It'll work.

The RTD sensor(Three wire) is built in Motor winding.This RTD sensor is connected to an Alarm Module which is located in MCC.We want to monitor the Temperature indication in the Central Control Room.This is the problem which need to be solved.

Thank you

Zia-ur-Rehman

Ah clarity!

In this case, I'd use an indicator with alarm contacts. I've been using Ero Electronics TIS indicators for years and they work very well. They can accept RTD inputs, provide 2 or 3 alarm contacts (depending on the particular model you select), and can also re-transmit the temperature signal as 4-20mA. They're small and very easy to use.

As indicated in at least one of the threads above the RTD is a small millivolt type of signal that cannot feed into to different type of monitoring devices without some loss of signal or introduction of noise and or grounding issues depending on the end devices. The best solution would be to bring it into a transmitter that can isolate the RTD as well as feed multiple inputs in the form of a 4-20ma or your flavor of transmitting device ie (Fieldbus). Now with that said there are probably other issues that were not included in the request and that would be where is it located and what area classification come into play. This would also need to be understood in completing the final equation of the selection and choice of wiring method (Intrisic Safe or Non Incendive) as well as the process that it will control.