Hi all,

Could anyone help me to write a FBD or Ladder logic or give me a guidance for below application.

5 Fans in total Duty/Assist/Assist/Assist/Standby arrangement. They need to rotate every 12 hours, so after 12hours fans are Standby/Duty/Assist/Assist/Assist, after another 12hours fans are Assist/Standby/Duty/Assist/Assist and so on...

Additionally we must have 5 digital inputs to know when fans are available/unavailable. If duty fan is unavailable(digital input 0) standby fan(if available) should run for remaining time until it arrangement rotates and another fan becomes duty. If Standby also unavailable then Assist fan should run instead.

Any help/guidance is appreciated !

Thanks

Hi,

Duty = Fan is running

Standby = Fan is off and only running/replacing Duty Fan when it is unavailable

Assist = Fans are running when temperature is high(will have temperature sensor to monitor temperature) 

After 12 hours they need to rotate.

Thank you!

Hi,

So to monitor temperature I am planning to use AM2 AI, temperature sensor output 4-20mA -10C to 40C.

Assist fans to be on when temperature is reached 26C and switched off when drops below 24C.

Thank you

Hello Auto_Gen

The tricky part is shifting the outputs every 12 hours. This can be done using a counter. Depending on the counter reading, a different assignment group is activated for the outputs (see example).

Regards Ella_68

(translated with Google)

This is my variant just change in T003 time block from second to hour and change every 12 hour

And check or it's working as you aspect