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Re: Off Topic - Looking for assistance with power sensors

 

Hi,

A few years ago I also tried to find out the calibration tables of the E4412/4413 power sensors, using my E4418B power meter. The "DIAG:DET:EEPR? eepromaddress, 1" command was definitely working (and returned the EEPROM location content), where I looped eepromaddress from 0 to 2047 (the address seems truncated to 11 bits, so using addresses higher than 2047 interprets the modulo 2048 part). I compared the read value with the dumped EEPROM content, and it matches. The second parameter when the content is read, '1',? is the number of bytes. I used reading only one single byte in a loop, but multiple bytes also can be read.

I tested also the EEPROM writing, if my notes are correct it is "DIAG:DET:EEPR? eepromaddress, eepromvalue". There were (several) checksum bytes for sure, if one single bit was altered in the content, at startup the sensor has been declared defective (corrupt table). But I didn't succeed to decrypt the table locations and checksum calculation.

In one of the EPM power meter manuals (probably this document is the source of inspiration : 9018-01324.pdf) I found some service commands, which I tested. The results are listed in the attached text file.

BR,

George/Gyorgy

On 5/22/2025 12:04 PM, Razvan Popescu via groups.io wrote:
Hi,

I will check my notes. I remember there were some GPIB DIAG and INIT commands that are not documented.

If you look at the PS-Cal and SureCal calibration software you will see they can read/write the new values via the power meter GPIB commands. Maybe for the newest sensors it is a little bit more difficult but for the HP branded E4413A that I had it was OK.

Regards,
Razvan

On May 22, 2025 8:43:32 AM UTC, "F1EKU via groups.io" wrote:
According to HPAK's technical documentation, it's impossible to write new calibration factors into the sensor because each time it requires calculating a checksum that the EPMs of the E4416/17/18/19 series cannot compute. They explain that for this, we must use the newer EPMs from the N1911/12/13/14 series. Personally, I've been able to read a sensor's entire block and write it back into another probe, but changing one or more values within the block always resulted in the inability to initialize the modified probe on an E44XX series power meter. Of course, HPAK uses an external program capable of calculating the checksum when they calibrate a sensor upon request and write the complete block, even with an E44XX power meter. Does anyone know the solution for calculating the checksum?

--
Gy?rgy Albert
Mob +40-722-304534

E4418_service_GPIB_commands.txt
E4418_service_GPIB_commands.txt

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