Electrical Connection
&
Mounting
Electrical connection
MeCAN connection is via 9 color-coded flying leads
(see diagram on page 1 ).
RED: Power supply positive DC
BLACK: Power supply negative DC
Connect these wires to a smooth DC power supply in the range
7 to 35 VDC. A 1 Amp anti-surge fuse is recommended in the
positive DC line. MeCAN operates with negative earth/ground
or fully insulated DC systems.
DO NOT
use MeCAN with
positive earth/ground systems.
YELLOW: CAN bus high
GREEN: CAN bus low
Connect these wires to the engine's CAN bus, using the
appropriate twisted-pair cable to J1939 specification. MeCAN
includes a non-removable 120 Ohm CAN terminating resistor.
VIOLET: Speed input signal
YELLOW I GREEN: Speed input return
GRAY: Speed calibration input (5k0hm potentiometer)
Connect the violet wire to a magnetic pickup or speed
sensor signal output. Connect the yellow/green wire to
the speed signal return wiring (or battery negative on
ground/negative-return systems). This input requires a
speed signal of 3 - 30 VAC rms.
Before calibrating the speed input (see section at right),
connect a 5k0hm potentiometer between the gray wire and
battery negative DC. MeCAN allows adjustment for speed
signals between 10 and 180 pulses per engine revolution.
The potentiometer can be removed in normal operation.
BLACK: Sender/switch common (negative DC)
WHITE: Coolant temp sender/switch input
ORANGE: Oil pressure sender/switch input
Part number E2501300 is designed for use with Murphy
ES series resistive senders (see separate product info for
pressure and temperature versus resistance data). For best
measurement accuracy, use insulated return (2-wire) senders.
Connect one terminal of each sender to the appropriate
MeCAN input lead; connect the other sender terminals to
MeCAN's Sender Common (black) wire. Where 1-wire
(negative DC/ground return) senders are used, connect
the black (sender common) wire to battery negative.
E2501200 is configured for use with low oil pressure and high
coolant temperature switch contacts that close to negative DC
on fault. For insulated return (2-wire) switches, connect one
switch terminal to the appropriate MeCAN input; the second
terminal from each switch (on 2-wire switches) or the body
ground (on 1-wire switches) must be connected to MeCAN's
sender/switch common (black) wire.
BLUE: shut
-down output
This open-collector transistor output gives a negative DC
signal, rated 250mA max, on detection of fault conditions:
part reference
E2501300
E2501200
Fault
(sender inputs)
(fault switch inputs)
oil pressure
< 10 psi
input closed to -DC
coolant temp
> 110
°
C/230
°
F
input closed to -DC
engine speed
> 3500 RPM
> 3500 RPM
The output latches following the fault condition and can be de
activated by removing the DC power supply. The output can be
used to drive a warning lamp, audible alarm, suppressed relay
coil or ECU shut-down circuit.
Enovation Controls - MeCAN MEC301 installation instructions
Speed input calibration
MeCAN's speed sensing input must be correctly calibrated
before speed data can be correctly transmitted by J 1939
CAN bus.
WARNING:
speed calibration requires the setting
of 2 DIP switches, which are environmentally
protected by an adhesive film. To maintain sealing
integrity, use a scalpel to carefully lift the film from
the DIP switch, make switch adjustments, then
replace the film firmly to ensure a good seal.
The speed calibration procedure is as follow:
a) Ensure minimum connection (details shown left) of CAN bus,
speed signal and (isolated) DC power supply wiring.
b) Connect a 5 kOhm potentiometer between MeCAN's
calibration input (gray wire) and battery negative DC.
c) Connect (to the CAN network) and power up a J1939
compatible RPM display, e.g., Murphy PowerView
®
PV101.
d) Set MeCAN switch DP1 to OFF (down) for calibration mode:
indicating LED
I •
••
••
•
•
;
•
•
-
-
•
- -
e) Set switch DP2 for the speed sensor range, if known:
- ON (up) = 10 to 62 pulses per rev
- OFF (down) = 55 to 180 pulses to rev
f) Run engine to known speed.
g) Power up MeCAN. The LED flashes rapidly to indicate
calibration mode.
h) Adjust the 5k0hm calibration potentiometer until the J1939
RPM display indicates the known engine speed. If the
indicated speed is too high/low and cannot be adjusted
downward/upward, power down MeCAN, switch DP2 to a
lower/ higher speed range, then repeat the procedure from
g) above.
i) Once the correct speed is indicated (and with MeCAN still
powered), switch DP1 to ON (up) to save the calibration
setting. Normal operation then resumes, indicated by a
continuously lit LED (if CAN bus traffic is detected) or a slow
flashing LED (if CAN bus traffic is not present).
j) Stop the engine and power down MeCAN. The 5k0hm
calibration resistor is not required for normal operation and
may be removed. Restart the engine, power up MeCAN and
check for correct operation.
Mounting
MeCAN uses an epoxy resin-filled polycarbonate case for
high
impact and environmental resistance. The case is compact
and light enough for inclusion in (or tie-wrapping to) an engine
wiring harness; or, using the actual product as a template, it
can be surface mounted by four M4 (0.15 in) holes - see
diagram on page 1 for approximate dimensions.
MeCAN's case is sealed to IP65, provided that the DIP switch
protective film remains intact. The exposed flying leads must
use connectors appropriate for the environmental sealing
required.
00-02-0665 revision D 19th August 2015
p2/3
