Installation manual

FuelMaster
®
Installation Manual
54
Pulsers
NOTE
In accordance with the NEC, “Class 1 circuits shall be permitted to occupy the same cable, enclosure, or
raceway without regard to whether the individual circuits are alternating current or direct current, provided
all conductors are insulated for the maximum voltage of any conductor in the cable, enclosure, or
raceway.” Ref: NFPA 70, para 725.26(A).
The FMU obtains quantity information from pulse output devices in the dispensing equipment.
These devices may be mechanical or electronic, depending upon the application. Usually one
pulse output device is required for each controlled hose. Some pulse output devices will provide outputs
for multiple hoses. In most cases the pulse output devices are optional equipment which must be
purchased separately. Syn-Tech carries a wide assortment of aftermarket pulsers which may be
purchased with your FuelMaster
®
order. Pulse options may also be purchased when placing the order for
the dispensing equipment.
Pulsers may provide quantity information in common increments referred to as divide rates. The most
common divide rates are: 1:1 (one pulse per gallon), 10:1 (10 pulses per gallon), and 100:1 (100 pulses
per gallon). The unit of measure may be something other than gallons. The FMU and FuelMaster
®
software may be programmed to record units of measure other than gallons, and any divide rate.
CAUTION
Do not wire 110 VAC into pulse return in the FMU. Pulse return is designed for a 12 VDC input.
Wiring 110 VAC into pulse return will damage the Pedestal I/O Board beyond repair.
ATTENTION
Ne câblez pas 110 V courant alternatif dans le retour d'impulsion dans FMU. Le retour d'impulsion
est conçu pour une entrée de 12 volts. Le câblage de 110 courant alternatif dans le retour
d'impulsion endommagerá le tableau Dedans/Déhors (I/O) du piédestal irréparablement.
FMUs provide a 12 VDC feed to pulsers, and are designed to receive a 12 VDC pulse return. Any voltage
greater than 12 VDC may damage the FMU, and any voltage less than 12 VDC may not return pulses
recognizable by the FMU.
The 12 VDC feed to pulsers is constant whenever AC power is being applied to the FMU. It is not
switched on and off with authorization. As such, it is possible to receive false “counts during reset”, pulses
generated and counted when a mechanical dispenser is resetting. See Pump Handle/Switch Detection,
Controlling counts during reset, in this section to remove or control counts during reset.
Pulse Filtering: DC pulser wires and AC control wires may be routed through the same conduit
providing all wires are insulated for the maximum voltage routed through the conduit. When routed
through the same conduit, the pulser wires should also be shielded to prevent bleedover from AC control
wires into the DC pulser wires/cable. Should bleedover occur, the FMU has provisions for removing the
bleedover. The FMU Satellite I/O Control Board has a bank of eight PULSE FILTERING dipswitches, one
for each of eight hose positions. When these dipswitches are turned on, they filter bleedover from AC
wires into DC pulser wires/cables. The maximum number of pulses the FMU can interpret when these
dipswitches are turned on is 9000 per minute.
If it is necessary to turn on these dipswitches, give careful consideration to the flow rate of the pump, and
the divide rate of the pulser being used. A 1000:1 divide rate will only allow for a 9 gallon per minute flow
rate (1000:1 divide rate x 9 gallons per minute = 9000 pulses per minute) while maintaining a maximum of
9000 pulses per minute.
It should not be necessary to turn on these dipswitches if 1) the pulser wires are shielded and insulated
for the maximum power carried through the conduit, or 2) the pulser wires are in a separate conduit from
any AC power wires. If the dipswitches are not
turned on, the FMU can interpret 120,000 or more pulses
230