VXI VT1422A - Manual (Page 276)

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 4 volt 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
V H and V L 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