Stepper Motor Operation
Current Level Setup (AG Command)
The AMP-44140 has 4 amplifier gain settings. The amplifier gain (in Amps/Volt) is set with the AG command as
shown in Table A8.4 for AGm=n, where m is a specific axis. The axis must be in a motor off (MO) state prior to
execution of the AG command.
AG setting Gain Value
n = 0 0.5 A/V
n = 1 1.0 A/V
n = 2 2.0 A/V
n = 3 3.0 A/V
Table A8.4: Amplifier Gain Settings
Low Current Setting (LC Command)
By default, Low Current mode is disabled (LCm = 0) which means that 100% of the current set by the AG command
will be delivered to the motor while the axis is holding position. An axis can be configured for Low Current mode so
either 25% of the current or no current will be sent to the motor while holding position. Low Current mode can
also be configured to wait a specified number of samples after a move is completed before lowering the holding
current.
Low Current Operation per Axis: YA n,n,n,n,n,n,n,n
LC setting Effect on Stepper Phase Current
n > 1 n samples after move finishes before going to 0% holding current
n = 1 25% holding current immediately after move finishes
n = 0 100% holding current
n < 0 n samples after move finishes before going to 25% holding current
Table A8.5: Low Current Mode configurations
ELO Input
If the ELO input on the controller is triggered, the amplifier will be shut down at a hardware level, the motors will
be essentially in a Motor Off (MO) state. TA3 will change state and the #AMPERR routine will run when the ELO
input is triggered. To recover from an ELO from the terminal, an MO followed by LC*=0, and an SH must be issued.
To recover from an ELO in DMC code, include WT2 after LC*=0 and before the SH command. TA3 will report ELO
has been cleared after the SH command is received by the controller.
It is recommended that OE1 be used for all axes when the ELO is used in an application.
See the Error: Reference source not found section in Error: Reference source not found for information on
connecting the ELO input.
Using External Amplifiers
Use the connectors on top of the controller to access necessary signals to run external amplifiers. For more
information on connecting external amplifiers, see Step A in Chapter 2.
A8 – SDM-44140 (-D4140) ▫ 229 DMC-41x3 User Manual
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