K Switch Inputs (1 - 16) - GE MM3 Instruction Manual

2.3 INPUTS AND OUTPUTS 2 INSTALLATION
k) SWITCH INPUTS (1 - 16)
All switch inputs are opto-isolated and operate at 120 V AC. The switch reads closed when 120 V AC is applied
to the switch terminal. This 120 V AC can be supplied by an external source providing that the source is in
phase with the MM3 supply voltage. When the MM3 control voltage switch is set to 240 V AC, the switch circuit
also operates at 240 V AC.
l) PROGRAMMABLE SWITCH INPUTS (1 - 10)
2
These 10 inputs can be programmed to one of a number of different functions. Some of the available functions
are: Setpoint Access, Lockout Reset, Plant Interlock, Auto Start, Remote Permissive, and Test. See setpoints
page S3: PROCESS \ PROGRAMMABLE INPUTS for complete list of available functions.
m) STOP (11)
If this terminal is de-energized, both contactor A and contactor B output relays will open causing the contactor
coils to de-energize. The stop input must be energized before the MM3 will process any start commands.
n) START A (12) AND START B (13)
When the start input terminals are energized, the corresponding contactor output relay is energized provided
all other valid start conditions are met. If any trip occurs, both contactor outputs become de-energized. Start A
input is used for all types of contactors, that is: Full Voltage Non-reversing, Reversing, Two-speed (low-speed),
Wye Delta Open Transition, Inverter, Slip Ring, Autotransformer, Part Winding, or Wye Delta Closed Transition.
Start B input is used for Reversing and Two-speed (high-speed) contactor control. Start inputs are usually
momentary unless two-wire control is used. Start A and B commands may also be initiated via the serial link.
o) LOCAL ISOLATOR N/O (14)
The local isolator NO auxiliary contacts are used to prevent motor starts in the event of the Local Isolator being
in the "open" position. To prevent starts, the MM3 produces a trip when the Local Isolator input is open. A Local
Isolator Trip is automatically reset when the Local Isolator is re-closed.
The Local Isolator input can be enabled or disabled as required. The factory default is disabled.
p) CONTACTOR STATUS (A: 15, B: 16)
The MM3 must know the state of the contactor at all times in order to detect discrepancies in contactor close/
open commands and also to display the state of the contactor. There are two contactor status inputs on the
MM3, one for contactor A, the other for contactor B.
Auxiliary contacts mechanically linked to the contactor itself are used to feed back to the contactor status
inputs. No status change following a "start" command indicates an open contactor control circuit and no status
change following "stop" command indicates a welded contactor. Appropriate messages and alarms are dis-
played for these conditions and the status can be read via the serial port.
If the motor contactor is externally energized, the MM3 will seal in the output relay and display an "EXTERNAL
START" message. If the motor contactor is externally de-energized, the MM3 will drop out the output relay and
display an "EXTERNAL STOP" message.
2-6 MM3 Motor Manager 3 GE Power Management