Syn-Tech Systems FuelMaster FMU-2500 Classic Installation Manual page 51

FuelMaster Installation Manual
®
for dispenser control circuits. The FMU does not provide power for the device being controlled. It
switches existing power. The FMU installer must find a circuit in the dispenser that interrupts the flow
of fuel. This may be an interruption of power to the dispenser reset mechanism, or a solenoid valve, or
a pump motor. The interrupted circuit must be a circuit which individually controls each hose offered
by the dispenser. To gain control, the FMU is inserted as a switch for that circuit. When the FMU is not
providing authorization, the circuit is open and fuel cannot flow.
The contacts of the switch are the LN and LD positions on terminal strips TB1 and TB2 of the Pedestal
I/O Board. The LN positions are the power-in (line) positions. The LD positions are the power-out or
authorization (load) positions. There are eight positions of LN (LN1, LN2, LN3, etc.) and LD (LD1,
LD2, LD3, etc.) for control of up to eight hoses per FMU.
FMUs have timers (No Pulse and Pump Finish) which will end a fueling transaction if not otherwise
ended by pump handle detection. If the pump motor is not using a conventional fuel dispenser with a
pump handle switch,
Dispenser installation manuals may provide wiring diagrams which illustrate dispensers being
powered through multiple circuit breakers. Up to four separate circuit breakers have been noted in
manufacturer's wiring diagrams for a dual hose dispenser. There were separate breakers for each
hose, the dispenser CPU, and the dispenser light circuit. Actual installations may have all these power
sources originating from a single circuit breaker. This means the original installer jumped power to the
applicable circuits after power arrived at the dispenser. To gain control of each dispensing hose while
maintaining constant power to the light circuit and CPU, the jumpers must be found and repositioned.
Otherwise, power may be sent to an unauthorized dispensing hose when another hose is authorized.
Whatever control method is selected, it must effectively prevent the flow of product out to the
dispensing nozzle when authorization isn't present.
Pump Handle/Switch Detection
When choosing the best control option, consideration must be given to the use of pump handle
detection. Pump handle detection is optional on non-DoD systems, but required on all DoD FMU
installations.
What it does:
if pump handle detection is not turned on and used to end a transaction, timers (No
Pulse Timeout and Pump Finish Timer) must be set to end the transaction. When timers are used to
end a transaction, they must be set to accommodate the longest fueling scenario to ensure the
transaction is completed before authorization is removed. The transaction remains authorized until the
timeout occurs. If someone finishes their transaction early and hangs the nozzle up when using timers
to end the transaction, some authorization time may be remaining for someone else to take the nozzle
down and pump fuel. The fuel pumped by the second person is incorrectly recorded against the
authorization started by the first person.
Another problem with timers ending transactions is the printing of receipts. If a customer finishes a
transaction quickly, the receipt won't print until the timers end the transaction.
These issues may be overcome by using pump handle (or switch) detection to end the transaction.
When wired into the dispenser connection, and turned on in the FMU configuration, pump handle
detection will end the transaction as soon as the pump handle is turned off. The next person fueling
has to start their own transaction. Receipts print as soon as the handle is turned off. Hoses become
available for new transactions more quickly.
How to get it:
pump handle detection for the FMU is attained from a source which provides power
when the pump handle or switch is turned on, and removes power when the pump handle is turned
off. The most common sources are a RESET COMPLETE signal in a dispenser, or the output side of a
pump switch. If the power source is 110 VAC, pump handle detection must be connected to either LN
or PHS (differences are explained below) on the Pedestal I/O Board. If the power source is 12 VDC, it
must be connected to the OK positions on the pulser connectors J4-J7 on the Pedestal I/O Board.
After a wiring connection is made, an FMU configuration setting must be made to turn on pump handle
49