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EQM Control Model
Components/Functions
3.
Ignition and Flame sensor
The spark plug for the Fenwal is both the sparkplug for ignition and the flame detection system. Fenwal has two
different styles. We use the two wire style. It will attempt to light and then check for a flame presence. Once the
flame is detected it will continue in sensing mode until a flame failure in which case it will go through another
purge cycle and attempt to light again. After 3 unsuccessful attempts it will go into lockout.
4.
EQM Board
The EQM board is command central for the EQM system. It is powered by 24VDC from the Power Supply /
Breaker. It also has 110VAC supplied to the relay that switches power to the Fenwal.
The 24VDC circuit on the EQM board provides power to:
•
The Temperature and Relative Humidity Sensors
•
The Modmotor for the burner butterfly valve control
•
All the low voltage DC power to the processor circuits
There is also a Modbus connection for VFD control.
The EQM board is also the wireless connection to the user’s phone or tablet through WiFi.
The EQM board is also the storage location for all data taken into the system. These can be downloaded
wirelessly.
5.
Temperature and Relative Humidity Sensors
The primary temperature and relative humidity sensor is located in the control box with the sensing tip exposed to
the heated air in the fan itself. This sensor is the basis for the EQM information and is very critical to successful
operation.
An optional additional identical sensor should be located in the bin headspace to monitor the air coming off the
grain before it exits the bin. This sensor is used to determine the amount of water removed and when drying is
complete.
6.
Modmotor and Butterfly Valve
The Modmotor receives 24VDC power directly from the Power Supply / Breaker. A variable 0-10VDC is
provided from the EQM Board to position the butterfly valve so that the proper temperature is attained. There are
some additional features:
•
The Modmotor has a spring return which brings the valve back to the zero position when power is
removed.
•
The butterfly opening can also be set to a desired position for easy ignition.
•
There is a visual position indicator on the valve body and actuator rod. Precise position also can be seen
on the dashboard.
