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IMS-MN-LMDA42C_A.pdf
Operation by hMT Modes
LMD CANopen
hMT On (Fixed Current)
With hMT enabled in fixed current mode, hMT will use the integrated encoder to maintain the
rotor/stator relationship within the set control bounds.
Commands for absolute or relative positioning, or slew at velocity, are received via the CAN
bus and processed through the hMT logic block. Feedback from the encoder is compared
with commanded clock pulses from the velocity generator. The output of this comparison is
used to keep the rotor/stator relationship within the control bounds, thus eliminating loss of
synchronization.
The variance between commanded position and actual position is stored in the lead/lag
register and is used to perform a position correction move if make-up is enabled.
The device will use the run and hold current settings for bridge current.
The following graphic shows a block diagram for a system with hMT enabled:
MPU
Bridge
Bridge
Current
Control
Motor
Encoder
Velocity
Generator
hMT Logic
CAN
CAN
Compare
logic
Position
Lead/Lag
Register
Rotor actual
position
Stator commanded
position
hMT On (Variable Current)
With hMT enabled in variable current mode, hMT will function the same as described for fixed
current mode with the difference that current control will be in variable mode.
In variable current mode, hMT will adjust the bridge current to the amount required to move the
load. The set run current (
RC
) will be used as the maximum threshold.
With hMT in variable current mode, the device may use less power and run cooler, depending
on load and duty cycle.
hMT On (Torque Mode Motion)
With hMT in torque mode, hMT will maintain constant torque on the load at the speed required
to maintain that torque.
The amount of torque used is set using the torque percent (
TQ
) parameter. The maximum
speed for torque mode is set using the torque speed (
TS
) parameter. When Profile Torque
Mode is activated the LMD will automatically go into torque mode.
