How do we connect rtd to the plc?

If you have a RTD module you can connect it directly to this module according to the module datasheet.
if you have an ordinary Analog Input Card (0-10v) or (4-20mA), then you have to connect the RTD to a transmitter to convert signal generated from RTD to the standard signal of the AI module, then connect the transmitter output to the AI card.

Hi Abdul,

        There are two ways to connect RTD to PLC are :

 1) If you have RTD module in PLC so it will get directly connected just need to know the wiring.

 2) RTD will be connected to transmitter which will generate signals( mA DC or V DC) to PLC analog modules.

Thanks

PLC have RTD input module you can directly connected to PLC,otherwise you need transmitter to retransmitting the universal input4-20ma or1-5 volt signal,this you connected to Analog input module

First Thing is the selection RTD type to be installed and connected to PLC as the Tempraute requirments. Normally the old PLCs have no have no RTC port, to connect RTD to them, the  R2I transmitter were used to interface the RTD to PLC through the AI card.Also it is important to know the numbers of RTD wires2,3, or4 wires to connect at the proper points in the module or the R2I transmitter.

Different type of plcs handle it dirrently. 

However in general, most of the PLCs have sperate RTD Modules. 

Depending on the type of RTD you are using , you can connect your RTD with the RTD Modules.

Normally there are3 wire RTD or4 Wire RTD, but wiring is mostly same as4th wire is left open. 

 

Having struggled with RTDs many years ago, I can understand how confusing this can seem to be.
An RTD is a very simple device, the resistance of which changes in proportion to the temperature in the area where the RTD is mounted.
RTDs are usually remotely located--remote in this sense meaning they are not located directly next to the PLC or monitor they are connected to.
So, wires have to be used to connect them to the monitors or PLCs.
Wire has resistance, and long wires have more resistance than short wires.
So, since the resistance of the RTD circuit is very important the resistance of the wires used to connect the RTD to the PLC or monitor needs to be accounted for (subtracted) in the conversion of the RTD resistance to temperature.
So, there is a third, and sometimes a fourth, wire that is used to calculate the resistance of the wire in the RTD circuit and that resistance is then subtracted from the total resistance of the circuit to arrive at the RTD resistance which is then converted to temperature by the PLC or monitor.
A simple "drawing" of an RTD is shown below.
Typically, the two wires coming from one end of the RTD are the same color (quite often white), and the single wire coming from the other end is a different color (red or blue, for example).
---------- | ----- | | | | RTD | | | | ----- |\ | \ | \ | ------- | ----------- You can use an ohm meter to determine which wires are which wires are which if there is any doubt with a particular RTD.
The two wires coming from one end of the RTD are sometimes called the "compensation" leads.
So, when you are connecting an RTD to a PLC or monitor you need to pay particular attention to how it is connected, because the single RTD lead must be connected to a particular terminal, and the compensation leads must also be connected to specific terminals.
For more information about RTDs, go to www.omega.com and search for RTDs; there is some really good information there.
You can also try www.wikipedia.org for information.
One more thing to note: Many digital controllers (PLCs and monitors) use a function called "multiplexing" to read RTD inputs.
This means that its very difficult to use some RTD simulators to simulate RTDs.
One needs a decade box, or a potentiometer, to simulate temperature to these kinds of devices.
If you have a specific problem, please provide more details and we can probably provide more assistance.

you must read the datasheet for yor rtd and plc type then you can know if the plc have it's own rtd port or not and then you will be able to wire your rtd to an analog port of the plc.
if you can't do it kindly send me the rtd type and plc model then i will send you the wiring for them

you need analog card for the PLC to receive the signal from RTD.  

To connect RTD usually through analog input, but some types of PLCs have their Owen RTD .
modules.
Also it is important to know the numbers of RTD wires2,3, or4 wires to connect at the proper points in the module.

analog resuilt (resistance or current ) so check the data sheet of your plc if its with AI option or you can use the A/D convertor (Analog to BCD  or what ever matches you) and you can creat the programe for comparasion or diffrance in plc also there are many ways to comply it as your requirments .texmate and motrona have big range and options ready to connect to almost logic controllers.

You can connect RTD directly to your PLC if PLC has option for RTD module.Or connecting RTD to fields transmiters and reading the value as4.20 ma