65
Operation by hMT Modes
IMS-MN-LMDE42C_A
Liberty MDrive Ethernet TCP/IP
Operation by hMT Modes
The LMDCE and LMDAE feature four operational modes for hMT:
1. hMT Off
2. hMT On (fixed current)
3. hMT On (variable current)
4. Torque control
The selected mode will have a major effect on how the device will operate during a move.
The hMT operating mode may also be changed either programmatically or immediately
provided a move is not in progress.
hMT Off
With hMT disabled, the motion block of the device will operate as a standard open loop stepper
controller/drive/motor.
Commands for absolute or relative positioning, or slew at velocity are received via the Ethernet
bus and processed as commanded, bypassing the hMT logic block.
The following graphic shows a block diagram for a system with hMT disabled.
MPU
Bridge
Bridge
Current
Control
Motor
Encoder
Velocity
Generator
hMT Logic
CAN
CAN
In bypass mode, the current control will be fixed at the set run and hold current percent levels.
Encoder functions such as stall detection and position maintenance are available in bypass
mode, provided that the LMD model is equipped with an encoder.
