Omega FMA 4000 - Manual (Page 28)

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The FMA 4000 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 following is a list of the Gas independent variables used for analog output
computation:
Index Name Description
25 AoutScaleV - DAC 0-5 Vdc Analog Output Scale
27 AoutScale_mA - DAC 4-20mA Analog Output Scale
28 AoutOffset_mA - DAC 4-20mA Analog Output Offset
7.3.1 Initial Setup
Power up the Mass 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 RS485 / RS232 communication between PC (communi-
cation terminal) and FMA 4000. The commands provided below assume that cal-
ibration will be performed manually (w/o Omega
® supplied calibration and main-
tenance software) and the device has RS485 address 11. If Omega ® supplied cal-
ibration and maintenance software is used, skip the next section and follow the
software prompts.
Note: The analog output available on the FMA 4000 Digital Mass Flow
Meter was calibrated at the factory for the specified gas and full scale
flow range (see the device’s front label). There is no need to perform
analog output calibration unless the EEPROM IC was replaced or
offset/span adjustment is needed. Any alteration of the analog output
scaling variables in the Gas independent table will VOID calibration
warranty supplied with instrument.
Note: It is recommended to use the Omega ® 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.