irondesk40
Member
Have a application I have been working on today using a compact logix to control temperature of molds. I am using a PID to get the Preset values for some timers that are being used to control solid state relays for the heaters.
I can heat the molds to the desired temperature and maintain the exact temperature within 1 degree F. What is happening is that as the mold is heating up the mold temperature will overshoot about 10 degrees but then will settle down and the PID maintains the desired temperature.
I have played around and found that if I add code to turn the heaters fully on all the time until I get with 95% of the desired temperature and then let the PID take control then it will only overshoot about 6 degrees.
Any advice on what to tweak in the PID to keep the overshoot to a minimum?
This equipment did have Fuji Temperature controllers operating in PID mode and they would overshoot about 10-15 degrees as well, but with the PLC I am trying to see if I can get the overshoot down to a minimum.
I can heat the molds to the desired temperature and maintain the exact temperature within 1 degree F. What is happening is that as the mold is heating up the mold temperature will overshoot about 10 degrees but then will settle down and the PID maintains the desired temperature.
I have played around and found that if I add code to turn the heaters fully on all the time until I get with 95% of the desired temperature and then let the PID take control then it will only overshoot about 6 degrees.
Any advice on what to tweak in the PID to keep the overshoot to a minimum?
This equipment did have Fuji Temperature controllers operating in PID mode and they would overshoot about 10-15 degrees as well, but with the PLC I am trying to see if I can get the overshoot down to a minimum.
