OPERATING INSTRUCTIONS
®
FORM 1554M (REV. A) 10/02
HYFIRE
®
7C CONTROL UNIT
PART NO. 676M
RPM Switch:
NOTE: This feature is not available on the HYFIRE
®
667S. The
built-in RPM switch can either turn an electrical load off or on
at a selected RPM. See below for more detail.
NC
RPM Limiters:
The HYFIRE
®
676M Control has three built-in RPM limiters. Each
one has a range of 1000 to 12,800 RPM in 50 RPM steps. On the
main display, there is a decimal point on the mode digit. When that
decimal point is lit up, the RPM limit is increased by 50 RPM.
C
NO
This is the RPM switch (mode 7) relay contact that is
normally closed. In other words, as long as you haven’t
RPM1
(Mode 1)This is the RPM limit that is always active if you
reached the point where the RPM switch is active, this
haven’t selected any other RPM limit.
contact remains connected to the “common” or “C” ter-
RPM2
(Mode 2) This is an auxiliary RPM limiter that is acti-
minal. You would use this connection if, for example,
vated when you apply 12 volts to the “RPM2” terminal on
you wanted to turn something OFF (such as a nitrous
the top-side connector. This could be a burnout limiter.
system) when you reached the RPM switch point. See
When selected, it overrides RPM 1 (the main engine
Example 1.
protection RPM limiter). See
Example 4.
This is the common terminal for the RPM switch (mode
RPM3
(Mode 3) This is the other auxiliary RPM limiter. It also
7) relay in the main unit. It is connected to the RPM
is activated by 12 volts on the “RPM3” terminal on the
switch, where it will switch the accessory connected to
top-side connector, and overrides both RPM2 and
the “NC” terminal OFF, and the accessory connected
RPM1. Use this limit as a staging (starting line) RPM
to the “NO” terminal ON when the RPM switch value is
limiter. See
Example 5.
reached. The “C” terminal can be used to switch either
to power or ground.
High Speed Timing Retards:
RET1, RET2, RET3 (Modes 4, 5, 6) These are all high-speed
This is the RPM switch (mode 7) relay contact that is
timing retard functions that are activated by 12 volts on the appro-
normally open. In other words, as long as you haven’t
priate top-side connector terminal. Each higher stage overrides
reached the point where the RPM switch is active, this
the lower stages, which means that you set each stage for exactly
contact isn’t connected to the “C” contact. You would
the amount of retard you want, rather than adding up each stage to
use this contact to turn something ON (such as a shift
get the actual retard. See
Example 6.
light or an air shifter) at a specific RPM. See
Example 2
and
Example 3.
NOTE: When you apply 12 volts to RPM2, RPM3, RET1, RET2,
or RET3 the display will switch to show that function. If you
have both an auxiliary RPM limit AND a retard selected, the
display will show the retard value.
See the accompanying illustrations for some examples of how to use
the RPM limiters, the RPM switch, and the timing retard functions.
1
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