PDL MICRODRIVE Series User Manual

Microdrive Series Instruction Manual
4201-109 Rev I
87
74 COMMUNICATIONS TIMEOUT SELECTION
Screen 74 COMMS T/O = OFF
Description SERIAL COMMUNICATIONS
TIMEOUT SELECTION
Options [OFF]/[1s]/[5s]/[25s]
FUNCTION Provides the option of tripping the Microdrive
(indicating COMMS TIMEOUT) if the time since
the last valid serial communications data
transfer has exceeded the communications
timeout period.
SETTING UP If a Microdrive serial communications option
module is not installed, leave this screen set to
OFF (the timeout feature is active whether a
Microdrive serial communications option module
is fitted or not).
If a Microdrive serial communications option
module is installed, select the required timeout
period.
Notes: Select a timeout period which exceeds the the
time between valid serial communication data
transfers.
If the serial communications baud rate (Screen
51) is set to OFF, the communications timeout
feature is disabled.
75 CURRENT LIMIT MODE
Screen 75 I LIM MODE = I
Description CURRENT LIMIT MODE
Options [I] CURRENT/[TQ] TORQUE
FUNCTION Selects current limit to control on inverter
current magnitude or on the torque component
of inverter current.
SETTING UP The Microdrive can be configured to limit the
absolute value of inverter current (Screen 75
set to I) or to limit the torque component of the
current (Screen 75 set to TQ).
The torque component of current is the current
which is in phase with the voltage. Owing to
the high efficiency of the induction motor over
a wide range of speed and load, the in-phase
current is closely related to the torque
generated by the motor.
By setting the I LIM MODE to TQ it is possible
to operate the inverter in torque limit control.
For linear control, however, the minimum flux
(Screen 25) must be set to 100% and the
inverter needs to be in the constant torque
region of operation (i.e., output voltage less
than or equal to input voltage).
The power factor of the motor will cause the
output current to be 10% to 20% higher than
the torque component of current.
Inverter current = torque current
power factor
For normal operation, set I LIM MODE to I
(current).
Torque limit control is useful over a wide range
of current levels, but becomes inaccurate
near zero frequency.
74
75

PDL MICRODRIVE Series Specifications

General

Brand	PDL
Model	MICRODRIVE Series
Category	Controller
Language	English