CANplus
TM
CP750-E
Installation Manual
9M02-1000-A501-EN
Revision A
4
Typical Wiring
The following subsections describe the typical engine interface wiring.
4.1 Power and Ground
The panel’s Power and Ground must connect directly to the battery posts and must not share
power and ground wiring with any other devices, especially any high current loads. The Power
line should have overcurrent protection in the form of current-limiting devices, fuses, circuit
breakers or fusible links to protect the harness wiring in the event of fault conditions.
4.2 ECU Power Out
The CP750-E can directly power the engine ECU.
4.3 Starter Power Out
The Starter Power Out is intended to power the starter relay, which is required. When power is
removed from the relay coil, the collapsing magnetic field generates a negative voltage surge.
Negative voltage surges can damage components. The CP750-E has protection against these
negative surges. However, it is still required to have a protection/suppression diode as close to
the relay as possible. Cattron recommends the use of relays that have this
protection/suppression diode built in. The protection/suppression diode must have sufficient
voltage ratings to survive and sufficiently suppress these negative voltage surges. Cattron
recommends a 1N4001 diode. Cattron sells a spike-suppressing diode kit (Part Number 630-
4007-77).
4.4 Resistive Senders
The Resistive Sender connections send system voltage out to the sender to obtain the current
value. It is required that the sender return connection be connected to a ground point (the
engine chassis, for example), as close to the sender as possible in order to get an accurate
measurement. If more than one sender is used, each sender should have a sender return
connected to a ground point near that particular sender. All sender returns should then be
connected together near the panel and the combined returns connected to the panel’s sender
return input.
4.5 CAN Bus Termination
CAN b
us requires two 120 Ω termination resistors each at the extreme ends of the wiring
harness. Typically, the engine ECU provides the termination resistor on its end (see the engine
documentation to verify). The CP750-E has a termination resistor that can be turned off and on
as needed. The CP750-E’s default configuration has this termination resistor turned on.
