Need help about Air Conditioner monitoring

Hi all,
My problem is: i have to design an air conditioner monitoring system (monitor: temperature, compressor current, pressure of condenser and evaporator). So, please help me information about:
- Pressure transmitter (4-20mA) for condenser and evaporator (to monitor low and high pressure of compressor)
- Temperature transmitter suitable for room temprature.

Many thanks,

This is a pretty broad topic, and you haven't really asked a question.

Are you having trouble finding information about the transducders themselves? Search the Thomas Register site: http://www.thomasregister.com/

Are you haveing trouble with the logic in the PLC? Ask specific questions.

Are you haveing trouble selecting I/O cards, or with wiring, or what. Ask specific questions.

Design of a system like this over the internet is not a good idea. Start with the transmitter information, see how they work, and then go to the PLC I/O, and so on.

Hi Tom Jenkins,
Thanks for your reply
Because i don't know the type of pressure transmitter to be used in my application, so i need help from someone has experience in this.

The air conditioner has 2 blocks: indoor block and outdoor block. At outdoor block, there are 2 ports to install pressure meters. Now, i want to install pressure transmitters (4-20mA), and then connect to PLC.i know that there are many pressure transmitter types, but what type is suitable for air conditioner ?.
(As diagram attatched, 2 ports are A and B)

Thanks Tom

Not knowing the refrigerant you are using, 500 PSIA for the high and 200 PSIA for the low pressures are probably sufficient. If you are using R410A, go about 20% higher. This assumes it is an air cooled application.

Make sure the sensor have not elastomers exposed on any of the wetted portion of the sensor as many refrigerants react to these in varying degrees. Some can cause swell rates of greater than 50%. I typically spec strain gage stainless steel sensors.

Using absolute pressure allows you to ignore barometric pressure fluctuations in calculating saturation temperature.

Thanks Mike W,
beerchug