DFA400 Rev150730
16
OPERATION
On power-up the owmeter is in normal operating mode. Information from a paddlewheel 
type ow sensor or from the datalink interface is processed and displayed. When a display 
is set as a remote, it receives all pressure and ow information via the datalink.
Datalink Interface
The  datalink  interface  is  standard  on  all  owmeters  and  provides  a  way  of 
connecting multiple display modules on a shared data bus. The DFA400 (digital 
owmeter), FPA400 (pressure/ow indicator), and FPA500 (pressure/ow indicator) 
series display modules can operate as independent displays or interconnected to provide 
remote displays, the display of ow rate through multiple discharges (summing), and 
the totalization of ow for multiple discharges (accumulation).
Primary Display Module
Primary displays are programmed with the module function Pri. A primary display 
receives inputs from the pressure sensor and ow sensor. When programmed with Id 
0, no information is output to the datalink. When programmed with Id 1 to Id 99, it 
provides information (via the datalink) to remote, summing, and accumulator displays.
Remote Display Module
Remote displays are programmed with the module function SLA (slaved to a 
primary). A remote display must be programmed with the same ID number as the 
primary display. It receives ow rate from the primary display over the datalink. All 
remote display features are programmed independently of the primary display. No 
calibration is necessary on a remote display.
Summing Display Module
Summing displays are programmed with the module function SU. A summing 
display shows the actual ow rate for all primary displays on the datalink except for 
those with Id 0.
Accumulator Display Module
Accumulator displays are programmed with the module function ACC. An 
accumulator display shows the total accumulated ow for all primary displays on the 
datalink except for those with Id 0. The value shown is times 100.
Note: A single display module can be used for both summing and accumulation 
functions. When program it as a summing display, pressing the TOTAL 
button shows total accumulated ow for all primary displays on the datalink.