Looking at the link to the PID, it looks like it is a REX C100, which I have a couple of. Whilst I know there are slight differences between the various makes of REX C100, as far as I know they all have an Autotune function and are capable of accepting a PT100 thermocouple. You may need to have a look at the instructions again, which even if you get an english copy aren't very user friendly.
On mine to get to Autotune press "Set" for 3 seconds to enter the settings menu
Press "Set" again to cycle through the menu items
Cycle through until you find the following menu item
Change 0000 to 0001 using the arrow buttons to turn autotune on. It will return to the temperature display on its own after a few seconds, It should now be in autotune mode. On the left hand side the second little light down should now be flashing to indicate it is in autotune mode (the light has AT onit if you look closely)
To change the sensor to PT100 you will need to unlock the other settings menus which you do by entering the settings menu (press "Set" for 3 seconds) and cycle through to the unlock menu item (using the set button) which looks like this
The code to unlock the other settings menu on my REX C100's is 1000, It may be different on yours, check the manual.
To go to the secondary settings menus from the temperature display press both "Set" and the left arrow button for 3 seconds. the display should show this
Press "Set" to cycle through this menu.
To set mine to accept a PT100 sensor I need to change SL1 from 0000 (K type) to 1000 (PT100) once again the values for yours may be different
There is another menu that you will need to change a couple of values
Go to the COD 0000 menu ("Set" and left arrow for 3 secs) and press the up arrow to change to COD 0001
You must change the DF setting to 0 else you will never get an accurate reading, else it'll think you are happy with an accuract of 2ºC
If you do decide to opt for a PT100 you will need to change the number of decimal places by changing the PGdP setting to 0003
Let me know if you need a copy of my manual PM me you email and I'll send you a pdf.
In the meantime here are the 3 main menus
The main setting menu is (press "Set" for 3 secs and cycle through items using the "Set" button)
The Cod 0000 menu (press "Set" and left arrow for 3 secs, cycle through menu items using the "Set" button)
Change SL1 for type of sensor
Change SL2 to set whether the dosplay is in Farenheit or Centigrade
I wouldn't change anything else in this menu.
The Cod 0001 menu ("Set" and left arrow to get to Cod 0000 menu then press up arrow to change to Cod 0001)
Apart from dF and PGdP you shouldn't need to change anything.
Hope that's been of some help to you, let me know if there's any thing you don't understand.