AW Gear Meters FEM-03 - Manual (Page 38)

FEM-03 Flow Monitor
Operation and Programming Manual
37
The FEM-03 does not discriminate any addresses. This means that any address can be written to as well
as read from. Writing to certain addresses can seriously alter the operation of the FEM-03. Use
extreme caution when attempting to write to the FEM-03 variable locations. Double check addresses
and variables before writing to the FEM-03!
Variable Addressing and Serial Command Variables
The FEM-03 stores all data it uses in two locations:

Run-Time RAM memory and

EEPROM Backup memory
The memory the device uses during regular operation is in the Run-Time location. All Run-Time variables
are in the RAM area of the microprocessor and are lost when power is removed from the FEM. All user-
accessible data locations are RUN-TIME data addresses.
So that the FEM-03 can retain this information at power down, it stores a copy of each variable in the
backup memory whenever the user programs a variable on the keyboard. The FEM also stores the
totalizer values to EEPROM memory once every 25 seconds. The FEM-03 recalls these EEPROM variables
to RAM memory on power up. When editing a variable using serial protocol, the UPDATE EEPROM Serial
Command Variable must be used afterwards in order to save a copy of any altered variables in the
backup memory. If this is not done, the FEM loses the new value in RAM and recalls the previous value
from EEPROM on the next power up.
All data is in Hexadecimal form in raw Hertz. or pulses. The KFR and KFT along with decimal locations
must be used to manipulate the rate or total data into ASCII form with the programmed decimal places.
GRAND Total memory locations only update when the JOB Totals are reset or overflow. Therefore the
JOB Total memory location can contain zero until the JOB Total value transfers to the GRAND Total with
a Job Total reset or overflow. The actual total usage in at any given moment is the sum of the JOB and
GRAND Total memory locations.
The FEM-03 also uses some specialized Serial Command Variables including these commands:

Serial RESET

Update EEPROM

RELAY Override

FORCE mA Output
For serial reset of totals, DO NOT write over the Job or Grand Totals but instead use the specified
RESET TOTAL Serial Command Variable. In order to interrogate or write to the FEM-03, the RAM
memory locations of each variable must be known. Following are locations of the most significant
operating variables and FEM Serial Function Commands: