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Hi,

I found partially my notes regarding E4413A that I had from a friend.
What I did was the following:

1) Before doing any EEPROM sensor operations run the following command to stop the auto trigger from the power meter:

INIT:CONT OFF

2) Read the calibration table:
"DIAG:DET:EEPR? MemoryAddress,NumberOfBytesToRead"
Do not read more than 100 bytes, it will crash the power meter. In my case an E4418B. Table size depends on how many frequency points were calibrated. You can add additional points if you want for specific frequencies like ham radio bands. There is enough space in the EEPROM.
Only the calibration table for the 26.5 GHz model was exactly 256 bytes.
H33 model will have it bigger.

Important thing to note is that the calibration table starts at 569 for E441XA sensors.

You can only write at specific locations based on the following formula:
Start byte address in the EEPROM for each conversion entry is x*8+9
First 4 bytes are the frequency, next 2 bytes are the low CF and last 2 bytes are the high CF.

I will give an example below what will be the bytes values for a 50 MHz frequency and CF LOW 100% and CF HIGH 100%.

(0 * (2 ^ 24) + 0 * (2 ^ 16) + 195 * (2 ^ 8) + 80) / 1000 = 50 (MHz)
So if we consider that starting address is 569 for the E441XA sensors you will need to write the following bytes at the address starting 569.

569 -> 0
570 -> 0
571 -> 195
572 -> 80
---- This will cover the 4 bytes for the frequency at 50 MHz ----

Now the next 2 bytes will be for the CF LOW:

100 * (64 * 256 + 0)/2^14 = 100 (CF LOW 100%)

573 -> 64
574 -> 0

Since the value for the CF HIGH is also 100 the same bytes will be written to the addresses 575 and 576.


3) Write the calibration table:
DIAG:DET:EEPR MemoryAddress,ValueOfByte

Based on the values above the commands should be:
INIT:CONT OFF
DIAG:DET:EEPR 569,0
DIAG:DET:EEPR 570,0
DIAG:DET:EEPR 571,195
DIAG:DET:EEPR 572,80
DIAG:DET:EEPR 573,64
DIAG:DET:EEPR 574,0
DIAG:DET:EEPR 575,64
DIAG:DET:EEPR 576,0

This will update the sensor EEPROM for the 50MHz CF value only.
You will need to repeat the process for all frequency points that you need.

For the H33 you will have even more points but there is enough space.
I didn't figure it out where is the EEPROM entry for the Standard vs OPT H33 to convert a normal sensor to the H33 model.

When you finish you can run INIT:CONT ON or just Preset or reboot the power meter. It will activate the trigger again by default.

New sensors like E93xxA also have a temperature compensation table but I never had one to investigate it and even the broken ones on eBay are too expensive. I was told that hardware for 6 GHz and 18 GHz is the same but it is missing the calibration table.

I hope it helps. If someone can build a python script to automate the process it would be great, my programming skills are not very good and now I don't really have any free time... This would be a project for the winter.

Regards,
Razvan