Refrigeration Frequency inverter control

[Vedran0909]

Dear All,

Can somebody tell me where can i download some literature where it is explained the technology of working refrigeration system with example: 3 compressors, one is with frequency inverter, other direct with contactor, 6fans, PLC, 2 pressure sensors 4-20mA(LP and HP), temperature sensors(room and outside), etc.
It is for freezing meat for example.
There is one controller Eliwell EWCM9100 witch we would like to replace.

PLS if somebody can send me the link or by email the litterature explaining the ligic and control theory so we could write the program in PLC?

Any help is hugely appreciated!
Best Regards
Stanislas

[chilliwilly]

Do you actually have any knowledge of PLCs or designing basic controls for refrigeration or any other plant or machinery?

It can take quite sometime to study the programming methods and the basic logic functions of PLCs, such as ladder, boolean, and subroutine. Which make of PLC are you planning on using? Basically they're all the same, but with subtle differences.

Klockner Moeller brought out a really basic PLC some years ago, but I tended not to use on anything major as its logic function and capability was too limited for the kit that I worked on at the time. However I did use it as a modification to certain machines such as palletizers and conveyor end take off box fillers. There should be enough logic function for what you are trying to do, and they can be expanded for more inputs and outputs, and the beauty of them is they can be programmed from the PLC without the need of a hand held programmer or a laptop.

Maybe better to stick with tried and tested control methods like what's already on there, it will be a quicker install or uprade. Theres no real advantage with using PLCs on walkins or aircon unless a process is being used such as cutting the beasts up and weighing them into portions. And in the case of the aircon, a small building services management system could be designed to control maybe four or more independently piped splits. Or a central packaged unit thats ducted to control the zoned grills/registers.