I am looking for a microcontroller solution to the following application:
A process signal in the range 0-10VDC is input to the controller. The controller compares the input signal against a high setpoint and a low setpoint. If the input is below the low setpoint, a relay output energises. If the input is between the low and high setpoint, the relay is de-energised. If the input is greater than the high setpoint, the relay energises.
The response of the relay should be time delayed (between 0 and 5 seconds) to prevent temporary changes in the input affecting the output.
I would have to program the controller so that the setpoints and time delay could be adjusted from the front panel using a LCD display.
The power supply needs to be 24VDC.
I have looked at the following models: Siemens Logo Telemecanique Zelio Logic Controller IDEC SmartRelay Mitsubishi Alpha
I think all of the above would suit my purpose but I wondered if anybody had any experience with the A-to-D conversion on any of those models? Or perhaps could suggest a better controller not listed?
I'm a complete novice in the microcontroller field and would appreciate any comments. Thanks.