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Issue 2 22/4/98
MPC2000D
Thermsitor 1,2 or 3 Short Circuit.
This is a protection function that has no setting but the user must be aware of its function. When the thermistors are
short circuited (i.e. a very low impedance value) this function will trip the relay indicating which thermistor is short
circuited.
On occasion when the thermistor is short circuited the relay will instead trip on Channel 1(2 or 3) Trip. This is
because the relay reads the change in the thermistor value, a faster increase will give a Short Circuit Trip whilst a
slower increase will give a Channel 1 Trip. In these circumstances the trip that occurs depends on the external circuit
and cabling used. When the change is not quick enough for the MPC2000D to register an Short Circuit a Channel 1
Trip is registered first instead. This only occurs if the thermistor type is NTC.
9.6. Tripping/Alarm Options
This page contains the following settings for each protective function incorporated in the MPC2000D.
Trip
This setting range 'Enable' or 'Disable' determines whether operation of the protective function causes a trip to the
motor or not. This can be applied to an alarm such that an alarm can be made to give a trip.
Alarm
The option, 'Enable' or 'Disable' determines whether the protective functions cause an alarm to occur and is applicable
to both alarm and trip protective functions.
Auto Reset
The option 'Enable or 'Disable' allows self resetting of a fault or alarm once the fault is no longer present. In the case
of Thermal Overload or Too Many Starts faults the self reset will not occur until the capacity has cooled to 50% or
the Starts inhibit period has passed.
Panel Reset
The option 'Enable' or 'Disable' allows reset of a latched fault by pressing the reset button on the MPC2000D
functional keypad, irrespective of the state of the Authorise input. If this feature and the Auto Reset functions are
disabled the only way to reset the fault locally is by use of the Reset button when the Authorise input is closed.
Remote Reset
The option 'Enable' or 'Disable' allows resetting of a latched fault by the PLC Reset input, provided that the unit is in
remote control and PLC control.
The following list details all of the MPC2000D protective functions for which the above settings are included.
