CHAPTER 5: SETPOINTS
489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL 5–21
5.4 S3 Digital Inputs
5.4.1 Description
The 489 has nine (9) digital inputs for use with external contacts. Two of the 489 digital
inputs have been pre-assigned as inputs having a specific function. The Access Switch
does not have any setpoint messages associated with it. The Breaker Status input, may be
configured for either an 'a' or 'b' auxiliary contact. The remaining seven digital inputs are
assignable; that is to say, each input may be assigned to any of a number of different
functions. Some of those functions are very specific, others may be programmed to adapt
to user requirements.
Terminals C1 and C2 must be shorted to allow changing of any setpoint values from the
front panel keypad. This safeguard is in addition to the setpoint passcode feature, which
functions independently (see the
S1 489 SETUP Z PASSCODE menu). The access switch has no
effect on setpoint programming from the RS232 and RS485 serial communications ports.
5.4.2 Breaker Status
PATH: SETPOINTS ZV S3 DIGITAL INPUTS Z BREAKER STATUS
This input is necessary for all installations. The 489 determines when the generator is
online or offline based on the Breaker Status input. Once 'Breaker Auxiliary a' is chosen,
terminals C3 and C4 will be monitored to detect the state of the machine main breaker,
open signifying the breaker is open and shorted signifying the breaker is closed. Once
“Breaker Auxiliary b” is chosen, terminals C3 and C4 will be monitored to detect the state of
the breaker, shorted signifying the breaker is open and open signifying the breaker is
closed.
BREAKER [Z]
BREAKER STATUS:
Breaker Auxiliary b
Range: Breaker Auxiliary a,
Breaker Auxiliary b
Courtesy of NationalSwitchgear.com
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