Annealing with PID

Using EUROTHERM PID controller

If you are going to do annealing in the low-temperature (LT) heater and you need to keep precisely constant temperature, you might want to use a PID controller to keep track of thermocouple (TC) readings and adjust heater current for you.

How to make it work:

• Check that the cables of LT heater are connected to EuroTherm and the power supply. Do NOT connect the grounding cable of the TC!

• switch on power supply

• switch on output of the power supply

• check that EuroTherm is in Auto mode (there should be no text "MAN" on top of the screen). If it is in manual mode, press A/MAN button

• use arrows to adjust the setpoint temperature

After this the controller will try to reach setpoint temperature and keep it.

There is a limit on how much power it can use which is shown as percents of the maximum value. The max current of the power supply is ca. 12 A, 20% corresponds to ca. 2.4A.

If you are going to use low T (let's say below 300C), you might want to put this limit lower, otherwise it can overshoot in the beginning by using too much power. If you need higher T, then set the limit higher, otherwise you may not reach the desired T.

Note: we have set up three temperature ranges with different PID parameters, Eurotherm will select PID parameters including max output power automatically, you just need to set the temperature.

The ranges are: T1<200; 200<T2<450; 450<T3

However, this has not been tested yet (15 Dec 2025).

How to operate Eurotherm via PC

Open iTools Engineering Studio (there is an icon on the desktop).

Go to menu tab Device -> COM3.ID001-3508.

Open Parameter Explorer (it is located under "Load" button).

In the Browse tab in the left panel go to Loop and press on folder 1. After that in the explorer window you will see tabs with parameter tables, you need to change only two of them:

• In the Main tab TargetSP is the temperature setpoint

• In tab PID parameter OutputHi corresponds to the max percentage of the power that can be used by the heater

Rough estimates of percentage values based on calibration:

<300C — <10%

300-400C — 12%

400-500C — 18%

500-600C — 23%

600-700C — 27%

>700C — 30%

For sensitive samples it is better to start with lower values to be sure not to overheat!

How to change the power limit in percents manually:

• Press menu button (left) several times until you see Lp1 | Main

• Press up/down arrows until you find submenu PID

• Use round arrow button and find in the sub-submenu OPHi

• With up/down arrows set the limit (18% in the photo above)