Monitoring and Controlling Central Air Conditioners


Thread Starter


Dear Experts here,

I need some help.

I have a project of Automation project to monitor and control an central air-conditioning system. the system consists of 9 units water chillers and 34 units AHU. the 9 units chillers already has a PLC equipped with a Modbus RTU module. the PLC model is microtech III which specially for HVAC use.

For each AHU unit I will need: one analogue input, one analogue output, one digital output, and 2 digital inputs.

The user should be able to read information from the chillers through the modbus RTU module, and also to control the units, and also read information from AHU and control them as well. All information should be viewed on a PC with an HMI software.

So assumed to use logo 8 for each AHU and initiate a network between all AHU units. then to connect them to an S7-XXX as a server and central unit, and also to use this S7-XXX as a master to control the other 9 units chillers as slaves.

does such idea is possible? if so which CPU of S7 is perfect to handle such project?

and which is the most stable HMI software?

Or else please let me know your suggestions.

Many Thanks.