High Country Tek emc-3 - Manual (Page 7)

Page 7 of 39
emc-3 Controller Module
User Guide – Rev A
Theory of Operation
Normal Operation
At Power On, the module will not run the fans until the Startup Delay has expired.
The Startup Delay is set by entering a value into the EE-Memory location
“Startup_Delay_Seconds” using the PLM or SAE J1939 configuration messages.
After the delay the controller will check 2 inputs
before enabling the outputs:

The Minimum Engine RPM ( must exceed entered value ).
 The Ignition Switch ( must be set to ON/+V to allow operataion).
If the “Engine Minimum RPM” variable is set to 0 in EE-Memory, the emc-3 is
enabled whenever the Ignition Switch is ON (≥ 3.5
VDC
).
If the “Engine Minimum RPM” variable is set to a value greater than 0; if the
Engine RPM read from the EEC1 message is greater than the “Minimum Engine
RPM” set point and the ignition switch is on, the emc-3 is enabled. If the module
detects the Ignition Input as “Off” (≤ 1.5
VDC
) while there is a valid Engine RPM
message detected, the Module will be enabled as required and report an Ignition
Input Error. Fans will continue to run as demanded by the current configuration.
When the emc-3 is enabled, the cooling demand is determined by the values set
in the EE-Memory for each enabled input. Each input’s demand is converted to a
percentage for comparison and the highest demand will control the fan RPM
independently for each Bank.
If the “Bank n Fan Idle Enable” is disabled (0) in the EE-Memory, and the cooling
demand is 0, the fan is set to the “Bank n Off DYCY”. If the “Bank n Fan Idle
Enable” is enabled (> 0) in EE-Memory, that Bank will run at min RPM even
when the cooling demand is 0 as long as the emc-3 is enabled. The minimum
RPM is determined by setting the “Bank n Start DYCY” in EE-Memory.
The “Minimum Fan Cycle Seconds” setting in the EE-Memory determines the
minimum amount of time that the fans must run before stopping, assuming the
fan controller is enabled. For example, if the “Minimum Fan Cycle Seconds”
were set to 20 seconds and a Fan Banks demand rose above 0, the fans on that
Bank would start. Then if the demand dropped back to 0 after 5 seconds, the
fans on that bank would be set to the “Bank n Start DYCY” for the remaining 15
seconds of the “Minimum Fan Cycle Seconds” before shutting off. The “Minimum
Fan Cycle Seconds” has no effect if the “Bank n Fan Idle Enable” is set.