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Reading IGBT temperature on Geo Direct PWM amp


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We are trying to read the IGBT temperatures from some Geo Direct PWM amplifiers (GPL032) but it seems we are looking in the wrong place for the results or are interpreting them incorrectly.


Based on reading the Forums and manuals this is what we have so far.

First we set the following


Check sys.wpkey = $AAAAAAAA


Make sure Gate3.Chan[j].PackInData=0

Make sure Gate3.Chan[j].PackOutData=0


Followed by Gate3.AdcAmpCtrl = $C0000204 to move into enhanced mode and then Gate3.AdcAmpCtrl = $80000204 to return the IGBT temperature.


The Geo manual (April 5, 2006 on cover) only gives instructions for Turbo and non-Turbo (P.57 in PDF (p.49 officially)) but from other forum threads we believe we have this set correctly.


According to this manual "The 12-bit value of the IGBT temperature for each axis will be in the lower 12-bits of the register holding the B phase current for the axis." and from p.715 of the Power PMAC software reference manual we believe we should be looking in Gate3.Chan[j].AdcAmp[3]. Our first question is are we looking in the correct place?


The second question is how to interpret the data we find there. The GeoBrick user manual states "The baseline IGBT temperature is set at 25°C (77°F), with ADC bits [11-4] value of $21 (Hexadecimal). Above the baseline temperature, every additional 2.13°C (35.834°F) correspond to $1 hexadecimal ADC count. The maximum IGBT temperature for the Geo Brick Drive is about 125°C (257°F), or $5B Hexadecimal ADC counts." but I have been unable to find similar information for our amplifiers. Where can we find the relevant data for our Amps or is it the same?


Based on the values we see we know that we are doing something wrong. Any assistance or pointers the the appropriate manual data greatly appreciated.


Thanks in advance,


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Thanks for the information, I had not noticed the new version of the drive manual which is of great help.


Unfortunately even using the correct location does not yield the results we expected if the same interpretation is used. Following the process and looking at the lower 12 bits of AdcAmp[1] always shows the lower 8 bits to be 0 (where 0x21 = 25 degrees C would suggest some 1's be present).


Using the PMAC suite terminal gives the same results with the contents of AdcAmp[1] indicating the lower 8 bits to all be 0 as shown in the attached screenshot.




Any help working out what we may be doing incorrectly will be gratefully received.

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