2-94 MOP
MOP The Motor Operated Pot (MOP) function is one of the sources for the
frequency reference. The MOP function uses digital inputs to increment or
decrement the Speed reference at a programmed rate.
The MOP has three components:
• [MOP Rate] parameter
• [Save MOP Ref] parameter
• [MOP Frequency] parameter
MOP increment input
MOP decrement input
The MOP reference rate is defined in [MOP rate]. The MOP function is
defined graphically below
MOP rate is defined in Hz/sec. The MOP reference will increase/decrease
linearly at that rate as long as the MOP inc or dec is asserted via TB or DPI
port (the MOP inputs are treated as level sensitive).
Both the MOP inc and dec will use the same rate (i.e. they can not be
separately configured). The MOP rate is the rate of change of the MOP
reference. The selected active MOP reference still feeds the ramp function
to arrive at the present commanded speed/frequency (eg. is still based on the
accel/decel rates). Asserting both MOP inc and dec inputs simultaneously
will result in no change to the MOP reference.
[Save MOP Ref] is a packed boolean parameter with two bits used as
follows:
Bit 0
0 = Don’t save MOP reference on power-down (default)
1 = Save MOP reference on power-down
If the value is “SAVE MOP Ref” when the drive power returns, the MOP
reference is reloaded with the value from the non-volatile memory.
When the bit is set to 0, the MOP reference defaults to zero when power
is restored. The MOP save reference parameter and the MOP rate
parameter can be changed while the drive is running.
Bit 1
0 = Reset MOP reference when STOP edge is asserted
1 = Don’t reset MOP reference when STOP is asserted (default)
MOP dec
MOP inc
MOP reference
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