HI Forum Members,

I'm working on a project that requires PID.

The PLC I'm using is a CPU1214C DC/DC/RLY

The System needs to run as follows. An Extraction fan motor is connected to an inverter. The speed output is controlled using a 4-20mA signal which is provided by the PLC using a 6ES7 234-4HE32-0XB0 Analogue I/O card.

The airflow is measured on the extraction system, this is read into the PLC as an analogue signal using the I/O card as detailed above.

The required air flow is entered as a setpoint via the HMI. If the measured air flow is below the setpoint then the fan motor speed is increased until the measured airflow matches the setpoint. The PLC then maintains the air flow at the setpoint and adjusts the speed up or down as required.

So how do I go about creating the PID control for the system as detailed above.If anyone has an example program similar to this it would be great to see. I'm programming using TIA Portal V13 Update 6.

Thanks and regards

David

Taylor Electrical

HI Forum Members,

I'm working on a project that requires PID.

The PLC I'm using is a CPU1214C DC/DC/RLY

The System needs to run as follows. An Extraction fan motor is connected to an inverter. The speed output is controlled using a 4-20mA signal which is provided by the PLC using a 6ES7 234-4HE32-0XB0 Analogue I/O card.

The airflow is measured on the extraction system, this is read into the PLC as an analogue signal using the I/O card as detailed above.

The required air flow is entered as a setpoint via the HMI. If the measured air flow is below the setpoint then the fan motor speed is increased until the measured airflow matches the setpoint. The PLC then maintains the air flow at the setpoint and adjusts the speed up or down as required.

So how do I go about creating the PID control for the system as detailed above.If anyone has an example program similar to this it would be great to see. I'm programming using TIA Portal V13 Update 6.

Thanks and regards

David

Hello,

As your inputs are both continuous, so you can use PID Compact.You can find more information in onlinemanula of Tia portal or HERE as a breif introduction.As a sampe, I can only ask you to check the followwing officia sample:

How can you prevent the PID Compact controller of the S7-1200 from switching off when the controller is switched off and on again and in the case of invalid process values?

I hope this helps,

Hamid Hosseini