274 VT1422A Command Reference Chapter 7
CALibration
•<ref_ohms> must be within 5% of the 7500 Ω nominal reference resistor value
or a -222 ’Data out of range’ error will be generated. If this error occurs,
verify the external measurement equipment and run *TST? on the VT1422A.
•<ref_ohms> may be specified in kOhm (kohm).
•When Accepted: Not while INITiated
•Related Commands: CAL:CONF:RES, CAL:STORE ADC
•Send with VXIplug&play Function: hpe1422_cmd(...)
Command
Sequence
CAL:CONF:RES
(now measure ref resistor with external DMM)
CAL:VAL:RES <measured value> Send measured value to module

CALibration:VALue:VOLTage

CALibration:VALue:VOLTage <ref_volts> sends the value of the just-measured dc
reference source to the module for A/D calibration.
Parameters

Comments •The "expected" output values for the voltage reference source is:

0.9 * Nominal Range Value for the 0.0625 through 4volt ranges.
10 volts for the 16 volt range.
•Use the CAL:CONF:VOLT command to configure the on-board voltage source
for measurement by an external reference voltmeter via the Calibration Bus
terminals.
• A measurement of the source voltage can be made with an external multimeter
connected to the HCAL and LCAL terminals on the Terminal Module or the
VH and VL terminals on the Cal Bus connector when not using a terminal
module.
•The <ref_volts> value given must be for the currently configured range and
output (zero or full scale) as set by the previous CAL:CONF:VOLT <range>,
ZERO | FSCale command.
•<ref_volts> must be within 4% of the actual reference voltage value as read after
CAL:CONF:VOLT or an error 3042 ’0x400: DSP-DAC adjustment went to
limit’ will be generated. If the reading on the external reference voltmeter is in
excess of 4% error from nominal voltage, verify the voltmeter and execute
*TST? on the VT1422A.
Parameter
Name Parameter
Type Range of
Values Default
Units
ref_volts numeric (float32) must be within +10% or -50% of the
"expected" source output value volts