digi-tech AA-0377 User manual

User Manual
Frequency Relay
Module for Cars
AA-0377
Distributed by:
TechBrands by Electus Distribution Pty. Ltd.
320 Victoria Rd, Rydalmere
NSW 2116 Australia
Ph: 1300 738 555
Int’l: [phone]
Fax: [phone]
www.techbrands.com

Technical Specifications:
•Power: 12VDC
•Dimensions: 72(L) x 65(W) x 43(H) mm
Instructions:
•Decide what you will be using the unit for – detecting a
frequency that is rising to the trip point or falling to the
trip point. On the module, set the link LK1 to L/H for
rising, and set the link LK1 to H/L for falling (default has
been set to L/H)
•Connect the module according to the wiring diagram
depending on your use of the module. Incorrect wiring
will damage the module and your vehicle if you connect
it in the incorrect polarity:
oThree connections should be made to your car,
(1) +12V (ignition switched); (2) chassis (0V); and
(3) signal wire from car sensor:
Road speed sensor
ECU tacho output
Switching side of an injector
Crankshaft or camshaft position output
sensor
oUse the car’s wiring diagram to find these
connections, and then use a multimeter to check
that they’re correct (e.g. check that the +12V
supply switches off when you turn off the
ignition).

•The device that is to be triggered by the module will
normally be switched via the Normally Open (NO) and
Common (COM) relay contacts. Because this module
uses a double-pole, double-throw (DPDT) relay, another
completely independent circuit can also be switched
simultaneously.
Setting the Trip Point:
•If you want to have the shift-light trigger at 6000 RPM,
you don’t have to start off holding the engine at 6k.
Instead, adjust the VR1 trimpot until the LED comes on
at (say) 3000 RPM and then goes off again as the revs
drop. By adjusting the hysteresis pot VR3, you should be
able to alter how much the engine speed drops before
the LED turns off. With the system working as it should,
turn VR1 a little more anticlockwise to increase the trip-
point frequency and then blip the engine until it again
switches on the LED. By making changes to VR1 and
then assessing the results with blips of the throttle, you
should be able to set the trip point at the correct engine
revs.
NOTE: VR1 is a multi-turn pot so that the trip point can
be adjusted very precisely – it will never reach a clear
‘stop’ if you keep turning. If the LED flashes on and off
around the switch-point, increase VR3 by turning it
anticlockwise.

Notes:
•Never get any part of the module wet.
•Never attempt to open, modify or repair any part of the
module.
VR1 (upper limit) and VR2 (lower limit) are used to set
the input frequency.  VR1 : 100-500Hz; VR2 : 10-50Hz

Wiring Diagram: