LMX SERIES™ OPERATION MANUAL
SECTION 11:
Entire Contents Copyright
2018 by Pacific Power Source, Inc. (PPS) • All Rights Reserved • No reproduction without written authorization from PPS.
LMX Series Power Source Operation Manual
Page 429 of 463
11
Calibration
11.1
Calibration Interval
All units are shipped new from the factory with NIST traceable calibration. It is recommended to
perform an annual calibration check to ensure performance to specifications. Under normal
circumstances, no adjustment will be needed but can be made as part of the user calibration
coefficients.
11.2
Closed Case User Calibration
This section covers routine calibration that can be performed by the user. User calibration does
not affect the factory set calibration coefficients that were determined and set at the time of
shipment to ensure compliance with published specifications. Rather, user calibration can be
used to obtain enhanced performance at typical operating conditions by adjusting these user
coefficients at these conditions. For example, if the unit is used primary for testing 400Hz, three
phase 115V L-N three phase operation, calibrating the user coefficients to these operating
conditions against an external precision reference can provide enhanced performance versus
published specifications (See Section 4, “Technical Specifications”).
Since user calibration does not affect factory calibration settings, resetting all user calibration
coefficients does not invalidate the units specified performance and it can be used with all user
coefficients reset as needed.
Note:
There are no analog adjustment pots in this instrument and all calibration can be
performed from the front panel or over one of the digital control interfaces.
11.3
Equipment Required
The following list of equipment or equivalent is required to perform routine annual calibration
of the instrument. Current sensor options are determined by need for AC, DC or both.
Item
Make
Model
Notes
1
Keysight
34465A
6 ½ Digit DMM or equivalent
2
Current Transformer
(AC Only)
Pearson
Model 110, 65 Arms Max. 5000Apk Max. 0.1V/A +1/-
0%, Rout = 50 Ohms
http://www.pearsonelectronics.com/products/current-
3
Current Transformer
(AC)
LEM
Pearson Current Transformer
CURRENT MONITOR MODEL 110
https://www.pearsonelectronics.com/
Table 11-1: Required Calibration Equipment
11.4
Calibration Procedures
Calibration of output and measurements is performed by a single procedure so there is no need
to calibrate each separately. Calibration involves voltage and current full scale and offset on
each phase. For three-phase mode, this means there are twelve calibration points, for single-
phase mode, there are four.
The calibration can be performed manually using the Calibration menu (refer to Section 6.8.9 for
the location of the Calibration menu) or through the build-in web server using the web browser
