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

 

 

  

The HFG2.0 provides two two-wire alarm signals via the integral 17-wire 
signal harness. The discrete alarm outputs are solid-state switches which 
are normally closed. The user’s controller provides +24 VDC to complete 
the circuit. Refer to Figure 1-16 for typical connections. Refer to the 
General Specification Summary Table in Section 1.2 for alarm 
specification values. See Section 3.7 for additional details about alarms. 

The fault configuration for the FAULT alarm is programmable in the most 
recent generation

 of the HFG2.0 (factory-configurable only). If a fault 

condition occurs, the FAULT alarm switch will open, interrupting the circuit 
with the user’s controller. See Table 3-1 for the default configuration

.  

See Table 3-3 for a list of fault conditions represented by the FAULT 
alarm in earlier generations

 of the HFG2.0.  

The fault configuration for the OVERTEMP alarm is programmable in the 
most recent generation

 of the HFG2.0 (factory-configurable only). If a 

fault condition occurs, the OVERTEMP alarm switch will open, 
interrupting the circuit with the user’s controller. The default configuration 
for the OVERTEMP alarm is Motor OVERTEMP, where the circuit will 
open if the temperature in two or more of the motor winding exceeds 
135°C. See Table 3-2 for details about the default configuration

. 

In earlier generations of the HFG2.0, the OVERTEMP alarm is dedicated 
to Motor Over Temp 

 and Electronics Over Temp 

 faults. If 

the HFG2.0 detects that the temperature in two or more of the motor 
windings exceeds 130° C 

 or the electronics temperature 

exceeds 110° C 

 the OVERTEMP circuit will open (see Table 3-4). 

In generation 

, the Electronics Over Temp fault is assigned to the 

FAULT alarm. If the electronics temperature exceeds 110° C 

 the 

FAULT circuit will open (see Table 3-3). 

 

The HFG2.0 allows for RS232 serial communication through three wires 
in the integral 17-wire signal harness. The RS232 wires, Rx IN, Serial Tx 
OUT and Serial RTN, are used to communicate with a user-provided 
computer. Serial communication can be used to change the HFG2.0 set-
up parameters and to retrieve fault diagnostics. Contact Precision Engine 
Controls Corporation to request fault diagnostic software. See Section 3.8 
for additional details about set-up parameters. 

 

CH. 2: UNDERSTANDING THE HFG2.0