Read calibration data from hp3478a and write to file:
py hp3478a_cal_ram_util.py <gpib_address> <output_file_name>
Validate calibration data from file:
py hp3478a_cal_ram_util.py -v <calibration_data_file_name>
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byteidx| raw |offset|gain |chk| chksum validation |result|offset_const|gain_constant|range
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1: 13|@@@AGEBCDBANF|000175|23421|E6 | 25 + 230 = 255|Pass | 175| 1.023421|30 mV DC
14: 26|@@@@DABCB@@OC|000041|23200|F3 | 12 + 243 = 255|Pass | 41| 1.023200|300 mV DC
27: 39|@@@@@CBCNBNMI|000003|23E2E|D9 | 38 + 217 = 255|Pass | 3| 1.022818|3 V DC
40: 52|IIIIIGBCDNNJF|999997|234EE|A6 | 89 + 166 = 255|Pass | -3| 1.023378|30 V DC
53: 65|@@@@@@BC@OANJ|000000|230F1|EA | 21 + 234 = 255|Pass | 0| 1.022991|300 V DC
66: 78|@@@@@@@@@@@OO|000000|00000|FF | 0 + 255 = 255|Pass | 0| 1.000000|Not used
79: 91|@@A@@HBAOB@NB|001008|21F20|E2 | 29 + 226 = 255|Pass | 1008| 1.020920|All AC Volts ranges
92:104|IIIHIH@ECCOKA|999898|0533F|B1 | 78 + 177 = 255|Pass | -102| 1.005329|30 Ω 2W,4W
105:117|IIIIHI@EA@MKG|999989|0510D|B7 | 72 + 183 = 255|Pass | -11| 1.005097|300 Ω 2W,4W
118:130|IIIIIH@EMCNJG|999998|05D3E|A7 | 88 + 167 = 255|Pass | -2| 1.004728|3 KΩ 2W,4W
131:143|IIIIIH@E@CEKM|999998|05035|BD | 66 + 189 = 255|Pass | -2| 1.005035|30 KΩ 2W,4W
144:156|IIIIII@EO@EK@|999999|05F05|B0 | 79 + 176 = 255|Pass | -1| 1.004905|300 KΩ 2W,4W
157:169|IIIIII@ENCDJO|999999|05E34|AF | 80 + 175 = 255|Pass | -1| 1.004834|3 MΩ 2W,4W
170:182|IIIIIH@EBOEJO|999998|052F5|AF | 80 + 175 = 255|Pass | -2| 1.005195|30 MΩ 2W,4W
183:195|@@@@@DCEMNOLI|000004|35DEF|C9 | 54 + 201 = 255|Pass | 4| 1.034679|300 mA DC
196:208|@@@@@ACDCLENC|000001|343C5|E3 | 28 + 227 = 255|Pass | 1| 1.034265|3 A DC
209:221|@@@@@@@@@@@OO|000000|00000|FF | 0 + 255 = 255|Pass | 0| 1.000000|Not used
222:234|@@@HHACBE@BNB|000881|32502|E2 | 29 + 226 = 255|Pass | 881| 1.032502|300 mA and 3 A AC
235:247|@@@@@@@@@@@OO|000000|00000|FF | 0 + 255 = 255|Pass | 0| 1.000000|Not used
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Sample file with calibration ram data
@ : byte index 0: 0x40 ('@') Calibration mode is off | 0x4F ('O') Calibration mode is on
@@@AGEBCDBANF : 1:13 : 30 mV DC
@@@@DABCB@@OC : 14:26 : 300 mV DC
@@@@@CBCNBNMI : 27:39 : 3 V DC
IIIIIGBCDNNJF : 40:52 : 30 V DC
@@@@@@BC@OANJ : 53:65 : 300 V DC
@@@@@@@@@@@OO : 66:78 : Not used
@@A@@HBAOB@NB : 79:91 : All AC Volts ranges
IIIHIH@ECCOKA : 92:104 : 30 Ω 2W,4W
IIIIHI@EA@MKG : 105:117 : 300 Ω 2W,4W
IIIIIH@EMCNJG : 118:130 : 3 KΩ 2W,4W
IIIIIH@E@CEKM : 131:143 : 30 KΩ 2W,4W
IIIIII@EO@EK@ : 144:156 : 300 KΩ 2W,4W
IIIIII@ENCDJO : 157:169 : 3 MΩ 2W,4W
IIIIIH@EBOEJO : 170:182 : 30 MΩ 2W,4W
@@@@@DCEMNOLI : 183:195 : 300 mA DC
@@@@@ACDCLENC : 196:208 : 3 A DC
@@@@@@@@@@@OO : 209:221 : Not used
@@@HHACBE@BNB : 222:234 : 300 mA and 3 A AC
@@@@@@@@@@@OO : 235:247 : Not used
@@@@@@@@ : 248:255 : padding
raw bytes from calibration entry : @ @ @ A G E B C D B A N F
in hex : 0x40 0x40 0x40 0x41 0x47 0x45 0x42 0x43 0x44 0x42 0x41 0x4e 0x46
lower nibbles in hex (&0x0F) : 0 0 0 1 7 5 2 3 4 2 1 E 6
in decimal : 0 0 0 1 7 5 2 3 4 2 1 14 6
sum digits : ^-------------------------------------------------^ = 25
check digits : ^-----^ = 14*16 + 6 = 230
sum (should add up to 255) : = 255 (valid)
Requires pyvisa and drivers for National Instruments GPIB-USB-HS controller.
Multiple instruments can be daisy-chained with standard gpib cables. Single gpib-usb-hs interface can work with multiple devices.
Tested with National Instruments NI GPIB-USB-HS controller IEEE 488 on Windows only.
Source: HP3478A Service Manual p.3-12
