20
S C M O D E L
GPI flowmeters have a “K-factor” which is the pulse output per
unit volume measured stated as “Pulses Per Gallon” (PPG). In
a flowrate-measuring system, it’s desirable to have an output
signal that has been converted to a standard unit of measure
such as gallons. Such an output can then be used to drive “off-
the-shelf” display units and/or relays.
An electronic circuit performs this conversion by counting and
accumulating input pulses until the count reaches the known K-
factor. It then generates an output pulse. At that time the counter/
accumulator “starts over” with a new count, and this process
repeats continuously as long as input pulses are present.
The GPI Scaled Pulse Module presents a series of 10-position
switches by which the user can set the desired K-factor.
All user connections to the GPI Scaled Pulse Module are made
through rugged, convenient screw-terminal blocks, so that in
typical setups no soldering, “wire nuts” or electrical tape is
required.
This unit is not FM Approved.
NOTE: This unit is DC powered, requiring an input power sup-
ply of 5 to 30 volts.
• This product is not approved for use in hazardous locations.
• When applying external power to the transmitter, use DC
power only.
• Disconnect external power to the transmitter before detach-
ing or attaching input or output wires.
• Ground loops between sensor and user equipment can dam-
age the module and can be dangerous.
• Be sure O-rings and seals are kept in good repair.
Installation should be performed only by qualified person-
nel, and in accordance with local governing regulations.
Environmental
Avoid plumbing meter where the Scaled Pulse Module is:
• Subject to constant exposure to water or other liquids (oc-
casional low-pressure splashing will not harm unit if cable
entry points are well-sealed).
• Close to high voltage/current runs, DC motors, internal
combustion engines or frequency inverters.
• Excessive vibration.
Cable Guidelines
The open collector signal itself is very resistant to electrical
noise pickup and shielded cable is seldom needed except in
very “noisy” (electrical) locations and/or when very long runs
(thousands of feet) are used.
Sensor Cabling
• Some products come with 20 ft. of shielded cable.
• If you require a longer cable, a 100 ft. cable kit is available
from GPI, or use Belden 9363 cable. When wiring longer
lengths of cable, be sure to connect the shield to Module
COM ONLY! (Multiple shield connections may cause ground-
loop problems).
• Some trial and error may be needed because of the wide
variety of user conditions. Try to keep cable lengths short!
This manual refers to various models of GPI flowmeters. De-
termine what type of input the electronics will receive and what
type of output, if any, you require. Use the diagrams found in
the Wiring Diagrams section, if the unit is not already wired, to
correctly wire the system.
Determine maximum power supply voltage after determin-
ing maximum allowable voltage of all electronic devices
in the system.
The Scaled Pulse Module comes with 20 ft. of cable to connect
to power and output wiring.
Connecting the Equipment:
• Remove the faceplate by removing the four (4) corner screws.
• Attach wiring from your equipment according to the follow-
ing terminal connections and wiring diagrams, depending on
your circumstances.
CAUTION
SAFETY INSTRUCTIONS
INSTALLATION
CAUTION
WIRING
CAUTION
IMPORTANT NOTICE
Summary of Contents for GA
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