How to deal with Temperature sensor/probe compatibility > 500 Ohms on CRE COMPACT controller?_En_V1

If you have a standard or < 500 Ohms probe, please refer to the product technical documentation and use the Probe Library available on the i4Gen Suite.

At the moment, it is not possible to directly manage a sensor/probe > 500 Ohms from the different modules of the COMPACT range. To be able to use a sensor/probe > 500 Ohms, simply add a resistance in parallel to the sensor/probe you have connected to the analog inputs.

Here are the analog inputs on the rear face of every modules of the COMPACT range (here the rear face of an AMF COMPACT module):

For example, if you connect your sensor/probe to input 1, you will need to connect the resistor between input 1 and the Common pin. Like this:

Add a resistor in parallel is not the only thing you have to do to use your sensor/probe > 500 Ohms, you also need to edit sensors curves on i4Gen Suite.

First, select the paralleled resistor you need to add to always be under or at 500 Ohms at the maximum.

Here some examples for sensors up to 2500 Ohms:

Note 1: According to this table, if your sensor/probe value is not equal to the maximum value of each value range, the equivalent resistance will always be less than 500 Ohms. You must then, when setting up your curve on the i4Gen Suite, set your maximum value according to the value of your sensor/probe --> the maximum value of your curve will not necessarily be equal to 500 all the time. For example, if you have a sensor/probe of 1850 Ohms, the maximum of your curve will be 490.1 Ohms, not 500 Ohms.

Note 2: When you choose the parallel resistor that need to be added, you must take a resistance whose value is close to those of the second column of the table above. Be careful however, the value of the chosen resistance, if it is not equal, it must imperatively be higher than that in the table (while being close to the latter) in order to always have an equivalent resistance 500 Ohms.

If you absolutely want to have 500 Ohms as the maximum of your curve. Here is the formula allowing you to calculate the resistor to be paralleled:

RTot is the max value we want, it is equal to 500 Ohms

R1 is the value of your sensor/probe in Ohms

R2 is the resistance to be paralleled, also in Ohms

And  here a graph that showing us what resistor we need to parallel our sensor/probe in order to always have 500 Ohms at the maximum.

Note: If your sensor/probe has a value above 10 kOhms, you need to calculate it with the formula given above.

Then, use the curve editor and calibrate the measurement points to obtain a curve between 0 and 500ohms of Equivalent Resistor.

The i4Gen Suite has a curve editor, to configure them.

To access to the curve editer, follow theses steps:

    - Open the i4Gen Suite, go to the controller settings. Go to Inputs/Outputs and select Analog inputs.

- Then select Analog input 2 and turn type from Unused to Analog input. 

- Now you are here:

    You can change, if you want, the label of the Analog input 2 to rename it, you can also change the harware, the type of            sensor/probe and the unit related to it.

Ohm and temperatures values have to be entered here:

Don't forget to click on this button to valid your modifications: