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| alan.bain:
When playing with POKES and PEEKS it is worth making sure your meter is in calibration secured mode. The worst commands (e.g. the ones which alter the non-linear AD correction coefficient) are disabled then. PEEKS other than -8 are safe. I think this is the complete peek list. PEEK -7 is rather interesting as it lets you read the raw count from the AD (a combination of the counts from processor, U501 and the residual AD value). Most of the transformations to turn this into a result are affine but there is a small non-linear correction which is a function of the voltage at the input to the AD. I don't totally understand the reason for this. If anyone is interested I could dig out the function from my old notes. PEEK -12 lookup block table in ROM data using index to stored address PEEK -11 lookup NVRAM data by block using the index to stored address PEEK -10 hidden feature enabled? PEEK -9 No of rows in the block table PEEK -8 [unsecured] enable: ZERO DCV PEEK -7 adc raw value (combination of T2 count, U501 count and residual AD) with MZ adjustment PEEK -6 stack dump from last unexpected interrupt PEEK -5 is there an ext interrupt pending? PEEK -4 line freq 1 = 50Hz, 0=60Hz PEEK -3 ROM ref values for specified block number e.g. PEEK -2, 70, 0 PEEK -2 NVRAM values at specified block number PEEK -1, eeprom word from direct address by counting blocks read PEEK 0, ram byte PEEK 1, ram word PEEK 2, ram dword PEEK 3, ram float [Thanks to razvan784 for filling some gaps here!] The NVRAM storage is split into numbered blocks; the low part is for safe changes the high part is for calibration data and can only be written when unsecured. A few blocks as examples 70 count gain between T2 ticks and residual on 80C196 AD 71 non-linear correction coeff1 (quadratic) 73 non-linear correction coeff2 (cubic) 76 transform params for DC 1V range (multiplier, shift, NA, offset, ?) must be scaled for line/NPLC |
| iMo:
--- Quote from: alan.bain on January 14, 2023, 10:43:30 am ---.. If anyone is interested I could dig out the function from my old notes. --- End quote --- Any info on the internal working of the 34401A would be greatly appreciated!! |
| coromonadalix:
--- Quote from: imo on January 14, 2023, 11:49:35 am --- --- Quote from: alan.bain on January 14, 2023, 10:43:30 am ---.. If anyone is interested I could dig out the function from my old notes. --- End quote --- Any info on the internal working of the 34401A would be greatly appreciated!! --- End quote --- You already have a full service manual for them, it's a good start ? |
| iMo:
--- Quote from: coromonadalix on January 14, 2023, 02:33:21 pm --- --- Quote from: imo on January 14, 2023, 11:49:35 am --- --- Quote from: alan.bain on January 14, 2023, 10:43:30 am ---.. If anyone is interested I could dig out the function from my old notes. --- End quote --- Any info on the internal working of the 34401A would be greatly appreciated!! --- End quote --- You already have a full service manual for them, it's a good start ? --- End quote --- What info in this thread is available in the service manual?? Could you show it? :) |
| jaromir:
--- Quote from: alan.bain on January 14, 2023, 10:43:30 am ---PEEK -7 is rather interesting as it lets you read the raw count from the AD (a combination of the counts from processor, U501 and the residual AD value). Most of the transformations to turn this into a result are affine but there is a small non-linear correction which is a function of the voltage at the input to the AD. I don't totally understand the reason for this. If anyone is interested I could dig out the function from my old notes. --- End quote --- That is interesting indeed. I'd be very grateful if you could find this valuable information. I wonder if you tried to log both raw ADC value and result from the meter to see the relationship between those. --- Quote from: alan.bain on January 14, 2023, 10:43:30 am ---70 count gain between T2 ticks and residual on 80C196 AD 71 non-linear correction coeff1 (quadratic) 73 non-linear correction coeff2 (cubic) --- End quote --- Looking at reply 65 with example EEPROM dump, those are byte 0x70 (only single byte?) and word 0x71-0x72 and 0x73-0x74, right? How to interpret those values into the correction coefficients? |
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