Closed-loop Drive A1
85
The high / low gain switch can be controlled
externally by either:
•
a logic input
•
the serial channel.
The high / low gain switch can also be controlled
internal by:
•
the gain change level parameter (GAIN
CHNG LEVEL), which defines a percentage
of contract speed.
With the drive set to internal control, the speed
regulator will go into ‘low gain’ mode when the
drive senses the motor is above a defined speed
level. The defined speed level is determined by
the gain change level parameter.
An example of internal high / low gain control is
shown below.
High / Low Gain Example
TACH RATE GAIN
(Tach Rate Gain)
This parameter can be used to help to reduce
the effects of rope resonance. It should be
adjusted only after the INERTIA (A1), and
RESPONSE (A1) has been set correctly.
The tach rate function is available for high
performance systems that exhibit problems with
rope resonance characteristics.
This function subtracts a portion of the speed
feedback derivative from the output of the speed
regulator. The Tach Rate Gain parameter
(TACH RATE GAIN (A1)) selects a unitless gain
factor that determines how much of the
derivative is subtracted.
SPD PHASE MARGIN
(Speed Phase Margin)
This parameter sets the phase margin of the
speed regulator assuming a pure inertial load.
This parameter is only used by the PI speed
regulator.
RAMPED STOP TIME
(Ramped Stop Time)
This parameter is only used by the torque ramp
down stop function and sets the time to ramp
torque from rated torque to zero.
After the elevator lands and the brake is applied,
the torque ramp down function allows the torque
to ramp down at an even level. This helps
eliminate the ‘bump’ felt upon landing caused by
the torque being immediately dropped to zero.
A function unique to elevators involves the
interaction between the motor torque and the
mechanical brake that holds the elevator. Under
full load conditions at the end of a run, if the
brake is set and the motor torque is removed
quickly, some brake slippage may occur.
Therefore, the option of gradually reducing the
motor torque is provided by the Torque Ramp
Down Stop function.
Upon being enabled by the Ramped Stop Select
Parameter (RAMPED STOP SEL(C1)), the
torque command is linearly ramped to zero from
the value that was present when the ‘Ramp
Down Enable’ was selected.
The Ramp Down Enable has the following three
possible sources:
•
An input logic bit (EXTERNAL TB1)
•
The run logic – initiated by the removal of
the run command
•
The serial channel
The Ramp Down Enable Source parameter
(RAMP DOWN EN SRC(C1)) is used to select
one of the above options.
0%
contract
speed
low gain
mode
Response of
Speed
Regulator
8.0 rad/sec
10%
contract
speed
10%
contract
speed
Response of
Speed Regulator
8.0 rad/sec
HPV 600 Parameter Settings
HI/LO GAIN SRC = internal
GAIN REDUCE MULT = 80%
GAIN CHNG LEVEL = 10 %
RESPONSE = 10.0 rad/sec
Response of
Speed Regulator
10.0 rad/sec
0%
contract
speed
Response of
Speed Regulator
10.0 rad/sec
speed
reference
100%
contract
speed