Compressor Room PLC Panel

The compressor room at Montajes Hercal required the automation of several devices used in the workshop. The two air compressors, the dryer and two fans (one inside the compressor room and one outside) had to be able to be controlled both manually and automatically.

All the electrical protection elements (differential switch, circuit breakers) where chosen based on intensity calculations of the engines that were to be powered through the panel.

The machining of the panel started with a clean metal sheet where the PVC channels, DIN rails and the rest of the elements that formed the shape of the panel where assembled.

The controller used was an old OMRON CQM1H and the HMI device was an also old NT30C programmable terminal.

Controlled elements

The following elements had to be controlled:

• Main air compressor.

• Secondary air compressor.

• Air compressor dryer.

• Compressor room interior fan.

• Exterior fan.

Requested features

The following features had to be implemented:

• Time control (start time, finish time and week days) for all the controlled elements.
• Manual control of all the elements, overriding time control until next automatic activation/deactivation.
• The activation of any or both of the compressors automatically activates the dryer.
• Activation of the interior fan is also controlled by a manual thermostat.
• Ability to adjust the time of the HMI panel.

Challenges

All the screens had to be designed taking into consideration the small resolution of the terminal (320×240) and its few touch panel switches.

The PLC didn’t have an internal clock so time had to be established in the HMI panel and sent back to the PLC for all the time related programming.