Introduction

When you turn on the power for the first time after you purchase an E5_N Temperature Controller, and set the control method into PID as well as change the SP, The self-tuning (ST) will start. If the external heater is OFF at this time, the E5_N determines that the PID calculation is not properly processed, and shifts to the limit cycle tuning method. In limit cycle tuning, the outputs are forced to turn on and off to determine the PID by analyzing the temperature (PV) change.

Explanation

Due to ambient air and the heat of surrounding machines, the temperature of the to-be-measured-PV goes up. This makes the E5_N shift to the limit cycle. It turns the outputs OFF and waits for the temperature decline. However, the temperature remains high due to above (external) factors, and the outputs are kept OFF even when the SP is then set to 130℃. In this situation, the temperature of the control target whose temperature is measured does not rise even the external heater is on.

When you use ST (selftuning), be sure to turn on the power on the load which is connected to the control output before or at the same time when temperature controller starts operation. See the extract from the Users Manual in below: