Hi everyone,

I have a process that I want to control with LOGO.

The process has different steps: 

1. Keep temperature 45degree using a heater with ON|OFF(digital output) for 10 min.

2. After step 1 increase and keep the temperature 60 degrees using heater with ON|OFF(digital output) for 25 min.

3. After step 2 increase and keep the temperature 80 degrees using heater with ON|OFF(digital output) for 35 min.

I tried using PI controller but it was not possible to connect DQ to the output for keeping the temp at specified value.

For the timer, I  have no idea how to measure exactly the duration when it reaches to the specified temp and then move to next step. 

I really appreciate if anyone can help me.

Best regards

Shouldn't it look like this:

Step 1: Heat up until 45°C is reached.
Step 2: Keep temperature at 45°C for 10 minutes.
Step 3: Heat up until 60°C is reached.
Step 4: Keep temperature at 60°C for 25 minutes.
Step 5: Heat up until 80°C is reached.
Step 6: Keep temperature at 80°C for 35 minutes.

But what should happen when the 35 minutes of step 6 have expired?

ixo65

Shouldn't it look like this:

Step 1: Heat up until 45°C is reached.
Step 2: Keep temperature at 45°C for 10 minutes.
Step 3: Heat up until 60°C is reached.
Step 4: Keep temperature at 60°C for 25 minutes.
Step 5: Heat up until 80°C is reached.
Step 6: Keep temperature at 80°C for 35 minutes.

But what should happen when the 35 minutes of step 6 have expired?

Yes, exactly should be like this.

Step 7 would be then turning off the heater and turning on a light. 

yes. it solved my problem.

Thank you very much.