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User Manual – Rev J
To select the MEAS CAL screen, follow the same steps as outlined above but select the MEAS
CAL entry. If another CALIBRATION screen has been accessed since power-up, no password
is needed. Otherwise, enter the same password as indicated above.
6.3
Voltage Measurement Calibration
The CS Series controller measures voltage and current by digitizing both voltage and current
waveforms on each available output phase. This data is subsequently processed and used to
calculate all measurement parameters such as VRMS, IRMS, Power, VA, Frequency etc. To
calibrate all measurements, only the voltage and current measurement need to be calibrated
specifically. All other measurements are derived from these.
Note: The Agilent HP 34401A Digital Multi meter (or higher AC accuracy DMM) must be
used for the following calibration. The DMM must be set to the AC HI ACCUR
mode for all AC measurements.
To calibrate all voltage measurement functions, the desired value for the measurement value of
voltage must be entered for each calibration coefficient. Make the indicated adjustments by
entering in the external DMM measurement value. This should be the value indicated by the
external DVM.
1. For 3000CS/4500CS: Connect an 18-ohm 1.5 kilowatt resistive load across each
output phase. Use a 100 mOhm current shunt of sufficient power rating in series
with the load to measure the AC load current. For multi-box systems, a 10 mOhm
current shunt will be required.
2. Connect the external AC DVM between the External Sense Neutral and Phase A
terminals. Select the Ext Sense mode, program the output relay on, ALC mode off,
400 Hz and 7.4 amps.
3. Go to the Measurement Calibration screen by repeatedly pressing the MENU key
until MEAS CAL is displayed. Move the arrow cursor to point to this screen and
press the ENTER key. If the password has been previously entered it will still be
displayed. The encoder may have to be moved up and back on value to allow the
password to be reused. If the password (135) is not displayed it will have to be
reentered. Press the PHASE key so only the ∅ A is indicated.
4. Move the arrow to point to MVOLT and dial in the exact voltage indicated by the
external AC DVM for the Phase A output. Press the ENTER key and wait until the
new calibration coefficient is displayed. Save this value by pressing the ENTER
key.
5. Repeat steps 2 through 4 for B and C phases.
Note: For multi-box power systems, eg. 9000CS/2, the voltage measurement calibration
should be done with only the Master power source. Remove all auxiliary power
sources and disconnect the system interface cable to the Master power source.
6.3.1
Single and Three Phase Modes
As indicated earlier, for 3-Phase power system, repeat the preceding steps for the Phase B and
C outputs. The order in which the outputs for each phase are calibrated is not important.
Press the PHASE key to select each output to be calibrated. Monitor the output of the
respective phase by moving the HI input of the Digital Multimeter and the current shunt as
needed. The LO input should remain connected to the common LO of the sense connector.
California Instruments
CS Series
91
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