Hamilton Sundstrand Company Gas Fuel Metering Valve HFG2.0 User Manual

 

 

The Full Span (Maximum Flow) position correlates to a DEMAND signal 
of 20 mA. The maximum Span possible for the HFG2.0 is 1.0 inches due 
to the configuration of the valve assembly. The maximum Span possible 
for the actuator used in the HFG2.0 is 2.0 inches due to its mechanical 
configuration. 

The Span value in the Set-Up parameters has a default setting of 1.0 
inches of retraction to allow for the distance between the mechanical stop 
in the valve and the mechanical stop in the actuator. (The default 
definition of Home is Extend, so default Span is a retraction.) 

Linear interpolation of the DEMAND signal in the range between 4 mA 
and 20 mA is the default condition, as specified in the Set-Up parameters. 
With linear interpolation, a DEMAND signal of 12 mA (midway in range of 
DEMAND signal) will correlate to a position at 0.5 inches (midway in the 
1.0 inch span). See Figure 3-2 for an illustration of linear interpolation. 

Note: The actuator and valve position is linear relative to the 

DEMAND signal in the default condition. However, due to 
the physical profile of the poppets, orifices and soft seats, 
the resultant flow area will NOT be linear relative to the 
DEMAND signal. 

 

CH. 3: OPERATING THE HFG2.0