EPC-250 IOI 6-18 All rights reserved © ALTRONIC, LLC 2018
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3.0 WIRING
3.1
Power
When replacing an EPC-200, remove the 3-pin power terminal from the device
and plug it into the power input terminal of the new EPC-250. Power require-
ment is 24Vdc (48 watt max.).
The EPC-250 is designed to accept the Legacy EPC-200 wiring input termi-
nation, which provides an easy swap of the two 20-pin terminals with their
pre-wire arrangement.
Proper panel/system ground must be implemented to provide an alternative
path for fault current flow, and limit the voltage-rise induced on powered cir-
cuits, typically via lightning, welding, voltage spikes, or unintentional contact
with higher-voltages.
3.2
Discrete Inputs Sensor Wiring
Normally-open (N/O) sensors are wired with one wire to the bot-
tom terminal strip of the respective sensor number and the other
to engine ground, which should be the same as power minus (−). A
short jumper from the bottom terminal to the top terminal must be
connected for normally-open sensors (see wiring diagrams).
Normally-closed (N/C) sensors are wired with one wire to the bottom
terminal strip and the other to the top terminal strip of the respective
sensor number. Note that the short jumper wire must be removed.
Use a wire size between 16 AWG (max.) and 24 AWG (min.) to connect the
sensor switches to the terminal strip connector. Strip the insulation back 3/8"
and twist the exposed wires tightly together. Insert the exposed wire complete-
ly into the terminal strip and securely tighten the clamping screw. Wires run-
ning to sensor switches must be in good condition or replaced with new wires.
When running wires, take care not to damage the insulation and take precau-
tions against later damage from vibration, abrasion, or liquids in conduits.
An explosion-proof conduit is not required. Wires should be protected from
damage by running them in a protective conduit or in sheaths when required.
In addition, it is essential that the following practices be adhered to:
A. Never run sensor wires in the same conduit with ignition wiring or other
high energy wiring such as the AC line power.
B. Keep secondary wires to spark plugs and other high voltage wiring at least
eight inches (200mm) away from sensor and sensor wiring.
C. If it becomes necessary to check sensor switch, first DISCONNECT the sen-
sor from the terminal strip of the modbus terminal board. Applying voltage
to the Modbus terminal board through the sensor leads may damage the
device. The area should be tested as non-hazardous before such testing
commences.
3.3
Analog Sensor Wiring
For each analog monitored point, select a transducer—either an Altronic pres-
sure or temperature transducer listed above or one that outputs a signal in the
range of 0 to 5Vdc or 0 to 25mA. Mount as described above. Use cable as-
sembly 693008-x or similar to wire transducer to the Modbus terminal board.
An internal 5 volt sensor supply (500mA max.) is available to power the
Altronic transducers; see wiring diagrams. If the 5 volt sensor supply exits the
panel, it must be fused with a 0.5 ampere fuse. If 24Vdc powered sensors are
used, the 24 volt supply to them must be fused appropriately. Take caution
not to damage the insulation when installing and take precautions against later
damage from vibration, abrasion, or liquids in conduits.
3.4
Thermocouples and Thermocouple Extension Wire
Only ungrounded type J or K thermocouples may be used. Use thermocouple
extension wire of the same type as the thermocouple probe to connect to the
terminal module. Use stranded thermocouple wire having a moisture-resistant
insulation such as PVC; for higher ambient temperatures, Teflon- or fiber-insu-
Note: Voltage and current supplied
must be sufficient to operate all
transducers used in the installation.
NOTE: A power supply with an NEC
Class 2 or Limited Power Source
(LPS) and SELV rating is to be used.
This type of power supply provides
isolation to accessible circuits from
hazardous voltage levels generated
by a mains power supply due to single
faults. SELV is an acronym for
“safety extra-low voltage.” Safety
extra-low voltage circuits shall
exhibit voltages safe to touch both
under normal operating conditions
and after a single fault, such as a
breakdown of a layer of basic
insulation or after the failure of a
single component has occurred.
Note: The (+) and (-) terminals of the
EPC-250 are polarity sensitive.
IMPORTANT: Pressure transducers will
withstand overloads as high as 1.5
times rated pressure. If the overload
rating is exceeded, failure may occur.
Pressure fluctuations occur in most
reciprocating systems; pick the
transducer with a rating high enough
to prevent overload by peak pressures
of pulsations. It is recommended
that a pressure snubber be used
which will reduce the peak pressure
applied to the transducer. The life of
the transducer will be extended with
the use of a snubber or pulsation
dampener.
IMPORTANT: Do not exceed the
absolute maximum rating of the
transducers, 350°F (176°C) for the
691202/203-300 or 450°F (232°C)
for the 691212/213-450. Care should
be taken to protect the wiring and
connectors from contact with hot
surfaces.
