FAA Approved Installation Manual for the EDM-960 system
Report No 909
Primary Engine Data Management System
Page 12 of 45 Rev C
Date 12-12-12
When the installation is complete all wires should be secured using ties and carefully checked for interference,
rubbing or chafing with flight control cables or other moving parts.
10. Power Connection
The EDM-960 automatically accommodates either a 14 or a 28-volt electrical system. Master Bus power must be
individually provided, via three 5 amp circuit breakers, to the two DAU units and the EDM-960 head. See Section ‘
IMPORTANT: Insure the DAU ground wires are connected to the engine block. Any wiring extensions or additions
beyond JPI supplied wiring must be MIL-W-32759/16 or equivalent. The EDM-960 has a 8-second warm-up. No
connection to the aircraft dimmer system is required because the instrument dims automatically with reductions in
ambient light. The instrument is designed to reset at less than 10 vdc bus power, therefore the instrument may
reset on engine start (typical for 14 vdc systems). This is normal due to the starter loading down the battery output
to below 10 vdc.
11. Probe Wiring
When cutting the pair of leads to the proper length to connect to the probes, leave enough slack in the wiring so
that probe may be interchanged to an adjacent cylinder if necessary for trouble-shooting and servicing.
Thermocouple wire length is not critical and should be trimmed to any length as required for a clean installation.
The Temperature probe must be wired with the correct polarity. The temperature probe connects to its temperature
indicator with yellow jacket Teflon Chromel-Alumel wire supplied. Strip the wires as shown below—observing color-
coding.
1/4"
1 1/2"
Fold back wire
double before
crimping terminals
2 1/4"
Thermocouple wire harness
red
yellow
Terminate each wire with a crimp-on ring terminal, provided. The ring terminals may be crimped with a
“service-type” tool, however AMP part number 48518 crimp tool is recommended. Verify the quality of each crimp
with a sharp tug on the wire. The terminal should be impossible to pull off when crimped correctly.
shrink tubing
ring terminal
Place a ¼ x 4-inch sleeve over each pair of wires in the wiring. Connect the wire ring lug to the probe ring lug using
the supplied number 4 screws and nuts, placing the star washer
between
the ring lugs, not against the nut.
Important: place star waster between two ring
terminals and tighten nut and bolt as
necessary
to instrument
to probe
Slide the sleeve over the joint and secure with three tie-wraps.
1/4 x 4" sleeve
tie-wrap 3 places
The most common installation problems are related to poor quality terminations.
