Service manual
59
Post Repair Calibration
Calibration is required annually and whenever certain components are replaced. If certain control board components
(U13-16, U306-308, U320-326, U329) are replaced, the Electronic Load module must be recalibrated as described in the
Operating Manual.
If any input power stage component is replaced, the Current Monitor (IMON) circuit must be recalibrated. The IMON
adjustment procedure is as follows:
a.
Turn load off. Disconnect any connections to the input terminals. Remove top cover.
b.
Connect DMM between the IMON adjustment test points J2-1 and J2-3 as shown on the Power Board Component
Locations Diagram in the Module Service Manual.
c.
Turn Electronic Load on and adjust R226 (see the component location diagram) for a reading of 0 ±0.5 millivolts on
the DMM.
If the serial EEPROM chip U211 on the mainframe or U342 on the module is replaced, the Electronic Load must be
initialized first and then recalibrated.
EEPROM Initialization
Serial EEPROM chip U211 on the GPIB board stores the Electronic Load's GPIB address and model number as well as
other constants. The load was initialized (the EEPROM programmed) with the proper constants before the load was shipped
from the factory. If the GPIB board assembly or the EEPROM chip (U211) is replaced, the load must be reinitialized with
the proper constants by programming the following commands in the order indicated. After it has been initialized, the
Electronic Load must be recalibrated as described in of the Operating Manual. Module initialization is discussed in the
appropriate module Service Manual.
6050A
":CAL 1 ! turn calibration mode on
":DIAG:CAL:PRIM 0,6050" ! model number
":DIAG:CAL:PRIM 1,16645" ! model number suffix and GPIB address 5
":DIAG:CAL:PRIM 21,0" ! initial *SRE value
'':DIAG:CAL:PRIM 22,0" ! initial *ESE value
":DIAG:CAL:PRIM 23,1" ! initial *PSC value
"*RST'' ! reset factory default state
"*SAV 0 ! to location 0
6051A
":CAL 1" ! turn calibration mode on
":DIAG:CAL:PRIM 0,6051" ! model number
":DIAG:CAL:PRIM 1,16645 ! model number suffix and GPIB address 5
":DIAG:CAL:PRIM 21,0" ! initial *SRE value
":DIAG:CAL:PRIM 22,0" ! initial *ESE value
":DIAG:CAL:PRIM 23,1" ! initial *PSC value
"*RST" ! reset factory default state
"*SAV 0" ! to location 0