Aalborg PWE Digital - Manual (Page 60)

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Note: It is recommended to use the Aalborg ® supplied calibration and
maintenance software for analog output calibration. This software
includes an automated calibration procedure which may radically
simplify calculation of the offsets and spans variables and, the reading
and writing for the EEPROM table.
,
The PWE analog output calibration involves calculation and storing of the offset
and span variables in the EEPROM for each available output. The 0-5 Vdc output
has only scale variable and 20 mA output has offset and scale variables. The fol-
lowing is a list of the EEPROM variables used for analog output computation:
Analog Flow Output variables
Index Name Description
39 FoutScaleV - DAC 0-5 Vdc Flow Analog Output Scale
41 FoutScale_mA - DAC 4-20mA Flow Analog Output Scale
42 FoutOffset_mA - DAC 4-20mA Flow Analog Output Offset
Analog Temperature Output variables*
Index Name Description
43 ToutScaleV - DAC 0-5 Vdc Temperature Analog Output Scale
45 ToutScale_mA - DAC 4-20mA Temperature Analog Output Scale
46 ToutOffset_mA - DAC 4-20mA Temperature Analog Output Offset
5.2.1 Initial Setup
Power up the PWE Flow Meter for at least 15 minutes prior to commencing the
calibration procedure. Make sure absolutely no flow takes place through the meter.
Establish digital RS-485/RS-232 communication between PC (communication ter-
minal) and PWE. The commands provided below assume that calibration will be
performed manually (w/o Aalborg
® supplied calibration and maintenance software)
and the device has RS-485 address 11. If Aalborg ® supplied calibration and main-
tenance software is used, skip the next section and follow the software prompts.
Enter Backdoor mode by typing: !11,MW,1000,1[CR]
Unit will respond with: !11,BackDoorEnabled: Y
Disable DAC update by typing: !11,WRITE,4,Y[CR]
Unit will respond with: !11,DisableUpdate: Y