Specifications

FWMurphy – AS731 / AS732 installation section A: panel installation and wiring mi6128 revision G 10
th
Sept 2007 p4/6
A typical wiring diagram is shown in the panel on page 5.
Specific terminal functions are as follows:-
Terminal block 1 - 20
Pin Function
1
3
Negative DC power supply/ground
Positive DC power supply
Use a clean, noise-free DC supply between 5 and 40 V,
normally the engine's 12V or 24V battery supply.
The AS731/AS732 design is optimised for use with
negative ground (earth return) systems, but may also
be used with insulated (two wire) systems. These units
MUST NOT be connected to positive earth systems.
Pin 1 (negative DC) MUST be connected to ground/earth
before connection of the RS232 communication port.
WARNING: failure to connect pin 1 to negative
DC / ground before connecting the RS232 port
may result in damage to the AS731/AS732, PC
or laptop.
The wiring to the positive DC terminal (pin 3) should
incorporate a 5 Amp anti-surge fuse.
2 Charge fail input
A 'charge fail' condition occurs when this pin is switched
to negative DC. Pin 2 may be connected to the WL
terminal of a charge alternator (Autostart provides the
necessary excitation current), or to the 'charge fail'
output of a BC700 series charger, or direct to negative
DC via relay contacts which close on fault.
When used with a charge alternator, pin 2 may also be
programmed to detect an ‘engine running’ condition.
If a charge fail alarm is not required, leave pin 2 open
circuit and program the ‘charge fail’ setting to ‘not used’.
4 Positive DC (feed for relays)/Emergency stop
Pin 4 is a positive DC feed for the Fuel and Start outputs
(pins 5 and 6). If required, emergency stop switches
(push to break, mechanically latching types) may be
wired between positive DC and pin 4.
5
6
Fuel output
Starter output
These are positive DC outputs, rated to 16 Amps, for
the control of engine (energised to run) fuel and starter
motor circuits. Murphy recommend the connection of
slave relays, with suppressed coils, between these
outputs and the fuel and starter solenoids (see typical
connection circuit on previous page).
7
8
9
10
11
Program output (POP) 1a: Normally open contact
Program output (POP)1b – Normally open contact
Program output (POP) 2 – solid state, negative DC
Program output (POP) 3 – solid state, negative DC
Program output (POP) 4 – solid state, negative DC
These outputs may be programmed to give one of 50
signalling and control ‘actions’, e.g. ‘preheat’, ‘engine
running’, ‘overspeed fault’, etc. A full list of output
‘actions’ may be found in document mi6129.
Output 1 (pins 7 and 8) is a volt free, normally open
contact (see specification for rating info). The default
program action is set for ‘generator contactor’ control.
Outputs 2, 3 and 4 (pins 9, 10 and 11) are semi-
conductor outputs. Each output gives a negative
DC signal when active (maximum rating 500mA),
and is typically used to drive a remote slave relay:
connect the relay coil between the output and
positive DC, and suppress each coil with a flywheel
diode or suitable suppressor network (as detailed
left, and on the typical wiring diagram below).
Output 2 has default programming ‘common alarm’.
The default setting of outputs 3 and 4 is ‘not used’.
12
13
14
Input 1: Low Oil Pressure (LOP)
Input 2: High Engine Temperature (HET)
LOP/HET return/ground
These terminals allow connection of LOP and HET
resistive senders or fault switches. Before use,
the module must be programmed for use with the
specific type of sender (Murphy, Datcon or VDO)
or switch (open on fault or closed on fault).
Resistive senders allow the Autostart to measure
and display oil pressure and temperature. Senders
also enable a pre-alarm warning as well as a
shutdown response. For greatest accuracy and most
reliable operation, two wire senders should be used.
The sender should be connected between each input
and the common return wire on pin 14. One wire
(ground return) senders should not be used, since
small amounts of noise on the ground/chassis can
result in significant signal distortion and
measurement error.
Fault switches allow the trigger of a simple shutdown
response. A two-wire (insulated) switch should be wired
between the input and pin 14. For earth return switches,
leave pin 14 open circuit (to avoid ground loops).
Further details of sender options and characteristics
can be found in the AS731/732 programming
literature, document mi6129.
15
16
17
Input 3 (programmable)
Input 4 (programmable)
Input 5 (programmable)
These inputs may be used with remote contacts
(open or closed to activate) to trigger a range
of programmable ‘actions’, e.g. shutdown fault,
warning fault, lamp test, manual start, manual restore
(of mains supply), etc. (see document mi6129 for full
programming details)
The remote contacts should be wired between the
input and battery negative.
18 Remote start/mains fail input
Use this input to initiate an automatic engine start
in AUTO mode. Connect the remote contact
between pin 18 and battery positive DC. The input
may be programmed to initiate a remote start on
either an opening or closing contact.
ELECTRICAL CONNECTION (cont.)
Product Discontinued