GE 239 Instruction Manual page 24

2 INSTALLATION
undercurrent: Use as a process control output such as in a conveyor where an undercurrent
condition controls flow of product onto the conveyor or in a pump situation to control a valve.
Also can be used as an independent alarm. See setpoint 6 3527(&7,21?3+$6( &85
5(17?81'(5&855(17?81'(5&855(17 )81&7,21
serial port command: For remote control via the RS485 communications link, a command
can be issued to directly control this relay. This may be useful for control applications. See
2
Chapter 7: COMMUNICATIONS.
For further process control the auxiliary relay can be assigned to option switch 1, option
switch 2 , or thermistor function .
• SERVICE RELAY (32/33/34): If the 239 detects an internal failure during its self monitoring or if
control power is not present, the NO/COM terminals of the service relay will be open to indicate
that service is required. This relay is internally programmed to be failsafe so that in the normal
condition, with control power applied, the relay is energized and the NO/COM terminals shown in
Figure 2–3: TYPICAL WIRING DIAGRAM on page 2–4 are closed. Connect these relay contacts
to a suitable signaling input of a DCS system.
e) SWITCH INPUTS
Each switch common terminal 38/39/40/41/42 is internally connected inside the 239. A single com-
mon wire can be connected between any of these terminals and a remote switch common terminal to
reduce wiring if preferred.
ISOLATED
POWER
SUPPLY
• SETPOINT ACCESS (38/43): The access terminals 38 and 43 must be shorted together in order
for the faceplate keypad to have the ability to store new setpoints. Typically the access terminals
would be connected to a security keyswitch to allow authorized access only. Serial port com-
mands to store a new setpoint will operate even if the access terminals are not shorted. When a
2-8
Courtesy of NationalSwitchgear.com
239
RELAY
+29VDC
FILTER
TO LOGIC
OPTO
ISOLATION
10mA
PULSED
Figure 2–5: SWITCH INPUT CIRCUIT
239 Motor Protection Relay
2 INSTALLATION
TYPICAL
SWITCH
TERMINALS
COM
EXTERNAL
SWITCH
IN
819780A3.CDR
GE Multilin