Class1 107490 - UNI-Governor 107396 107269 software v 6 00 - Manual (Page 36)

35 C:\manuals\Uni-Gov-V6-107490
Miscellaneous
It is essential that the governor be powered at the same time as the engine ECM and that the
control signal does not drop out when the engine is started. This signal can be checked at the 12
way connector terminal 8 with a voltmeter. Valid signals for idle are 0.6• VDC and higher, for
maximum throttle 3.6 to 4.2 VDC.
The governor must have a throttle interlock (12 VDC) signal at terminal 12-2 in order to operate as
a throttle or to act on a fast idle input (12 VDC) at terminal 12-3. Additionally, a pump engaged (12
VDC) signal must be present at terminal 12-10 before it can operate in the pressure governing
mode.
If the governor is powered with the OEM Throttle interlock and the High Idle request active, it will
ignore the High Idle request. High Idle requires an active toggle.
The governor does not default to an operating mode, this means that the operator must select
which mode to operate in before the unit will respond. If the interlocks exist for pressure mode,
the first selection will be PRESSURE. Once a mode is selected, it remains in effect until the mode
switch is pressed, the idle switch is pressed, the unit is powered off, the OEM Throttle interlock is
lost or cavitation is detected.
The PRESET function is very useful to expedite initial pumping operations. It can also be very
useful to have both a THROTTLE and a PRESSURE preset. Any time that the PRESET switch is
pressed, the engine will go to that point either from a higher pressure/RPM or a lower one. You do
not have to be at idle for PRESET to function.
When increasing engine RPM from idle using the INCrease switch, the governor output must go
from its base idle output and cross the idle threshold of the engine being governed. This is very
similar to “taking up the slack” in a mechanical engine throttle cable. By using the PRESET
function, the “slack” is taken care of automatically and the engine will increase to a known
parameter eliminating the guesswork.
Note: A custom engine configuration can be programmed that will tailor the minimum idle output
for an application.
Cavitation (running away from water). The governor will react to a pressure drop below 30 PSI for
five seconds or more by dropping the engine to idle speed and showing LoSupply in the Message
Center. If the pressure climbs above 30 PSI before water loss is recognized, the 5 second timer
resets. This means that if the pump has some water, the governor may never “see” a continuous
pressure drop below 30 PSI and the engine could run at an advanced speed until it is manually
decreased. The maximum speed will be restricted to the last value plus the trim parameter, usually
less than a 300 RPM increase. If water is introduced during the period that engine speed is
advanced, a pressure spike could result.
Pump operators should be trained in all aspects
of governor operation and have knowledge
of all powertrain operating characteristics.