It's complicated..

I've got a switch Test/Auto/Off


In Auto mode..

I've got a fan that blows air through a heater battery to provide hot air . Everything is connected to a PLC . When I want to shut down the system , the fan will keep running for about 10 seconds to dissipate the heat from the heater battery and keep it healthy . PLC does everything automatic.

The problem comes when I want to do it without the PLC , in Test Mode ,when the PLC is disconnected, How can I keep the fan working for about 10 seconds after the heater battery stops. .

Thanks!

Why are you disconnecting the PLC to run in test mode? Is this part of the instruction? Model and make of the air handler please.

Thanks for replying , I've asked for a data sheet.. but no lock yet . ...do you have a best case scenario ?

Without instructions my guess is the fan doesn't need to run in test mode for the normal 10 seconds, but my puzzle remains as to WHY you disconnect the PLC to run a test without specific instruction to do so.


The problem comes when I want to do it without the PLC , in Test Mode ,when the PLC is disconnected,
Make and model numbers would help solve this quicker.