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6.2
Current Command Mode
LX drives can be operated in torque mode or current command mode using terminal pin
2 (CUR CMD) as an input for the current command signal. The command signal range
is ±10V. Terminal pin 2 is a bi-directional terminal with an input impedance of 20 kΩ .
Output impedance of the device driving the CUR CMD input must be 50W or less
(standard operating amp output). It serves as both an input for the current command
when operating in current command mode and an output for the current demand signal
generated by the speed loop when operating in velocity command mode.
When operating in current command, the Ixt limit circuit is not operational but the motor
current is still monitored. The High Irms output will go open circuit when the Ixt limit has
been reached and the High Irms LED will illuminate. The system controller must monitor
the High Irms output and reduce the current command when the voltage at that point is
high (not grounded to logic common)
Note: When operating an LX drive in torque mode, terminal pins 7 and 8 must
remain unconnected.
WARNING: NO AUTOMATIC CURRENT LIMITATION IS PERFORMED IN
CURRENT COMMAND MODE. It is the responsibility of the system
designer to implement current limitation by monitoring the high Irms
output.
6.2.1 Torque Helper Application
Torque helper applications can be easily implemented by interconnecting the drives to
share the same torque command from a master drive. To implement this, connect the
terminal pin 2 of the Lead drive (running in velocity mode) to the terminal pin 2 of the
Helper drive(s) (no connections to pins 7 & 8). This way the same current command is
being used by all the drives. Terminal pin 2 is a bi-directional terminal with an input
impedance of 20 kΩ.
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Section 6– Page 2
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