Custom Calibration
The customer calibration function is designed to allow better results for temperature correction than using the standard offset and gain parameters.
It serves to address the comment that the preceding Marathon sensor offered 3 point calibration that was a better fit for some applications than purely offset and gain parameters would provide.
Offset and gain parameters can be set manually or by using the Field Calibration function within the suppled DTMD software.
This Customer Calibration function not yet supported by DTMD and requires the latest firmware See Link
The LCD display can be checked via the Unit Setup menu:
With CUSTOM CALLI enabled, any correction provided by non-default Offset (0) and Gain (1) are nullified (last used settings are preserved but not used).
Programming the functionality requires a a correction string to be created (ICAL string) and the function to be enabled (SIC=1).
Up to 6 temperature points can be corrected.
For this example putty.exe was used and the following setting are recommended:
It is not necessary to utilize all six points. For example a standard "compensation string" would be (single space as separator):
ICAL=6 600 610 700 710 800 810 900 890 1010 1000 1400.5 1420.7
ICAL=6 (number of points) 600 (measured value) 610 (corrected value) 700 (measured) 710 (corrected) 800 810 900 890 1010 1000 1400.5 1420.7
Example Correction (5 points)
ICAL=5 600 610 700 710 800 810 900 890 1010 1000
Notes:
1. Integers or decimal points can be used
2. Lowest correction point must be greater than the sensor's lowest measurable temperature or the XB value
3. Command SIC=1 enables the function - remember the Offset and Gain parameter correction is nullified
4SIC=0 disables and reverts to the default method (offset and gain if set).
4. ICAL=0 clears the compensation string
5. ?ICAL allows you to check the string
6. Hint: Clear string before defining new string
7. You must check device calibration and build the correction table using default device offset and device gain values DO=0 and DG=1 - to avoid self cancelling effects when SIC correction is enabled
8. For ER sensors also check device gain top detector (1C/wide band) and device offset top detector (1C/wide band) DGT=1 and DOT=0
Special Note:
In DTMD, offset and gain values can be set and will display in the parameter list.
With SIC=1 the settings are not used.
With SIC=0 the settings are used.
Take care - if temperature readings do not change when offset and gain is adjusted, it is likely that the SIC setting is set to 1. You can check the SIC setting with ?SIC.
Recommendation:
We recommend when working with this SIC and ICAL function to set offset and gain parameters to default values.
The attached short video will take the user through the steps required to enable and setup the 6 point calibration correction function, after successful communication has already been established with a suitable terminal program.