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IM483 Operating Instructions Revision R032306
39
IM483 Operating Instructions Revision R032306
R e d u c i n g / D i s a b l i n g t h e O u t p u t C u r r e n t
The IM483 has the capability of automatically reducing the current in the
motor windings following a move. Use of this feature will reduce motor
and driver heating, thus allowing for cooler operation and improved
system power efficiency.
The output current may be reduced to the level needed to maintain mo-
tor holding torque by means of a 1/8 watt or higher, 1 percent resistor.
This resistor is connected between P2:1 (Reduction Adjust) and P2:2
(Current Adjust). The value of the reduced output current will also be de-
pendant on the current adjust resistor value as expressed in the equation
below. Figure 7.3 illustrates the connection. If no resistor is placed, the
current in the motor windings will be at the amount set by the current
adjust resistor when the motor is stopped and the driver enabled.
To reduce the current in the motor windings to zero between moves,
the drive may be disabled by pulling the enable/disable input (P1:5) to
ground by means of a sinking output on your controller or PLC, or by
placing a shunt between pins 1 and 2 of connector P2. Note that if the
controller continues to send step clock pulses to the driver, the internal
counter on the IM2000 controller ASIC will continue to increment unless
the driver is reset. This will only affect your system if the On-Full-Step
output is used for position monitoring.
The amount of current reduced will depend upon the value of the re-
duction adjust resistor (R
Red
) and the value of the current adjust resistor
(R
Adj
). The current will be reduced aproximately 1.0 seconds after the
rising edge of the last step clock pulse. The value of R
Red
is calculated
as follows:
I
Run
is the desired peak running
current. Range 0.4A to 4A Peak
I
Hold
is the desired peak holding
current. Range 0.2A to 4A Peak
I
Run
x I
Hold
R
Red
= 500 x
(
I
Run
- I
Hold
)
NOTE: Resistor leads should
be as short as possible to
minimize the amount of noise
coupled into the driver!
P
2
P2:1
P2:2
Current Adjust Resistor
1/8 W 1%
Reduction Adjust Resistor
1/8 W 1%
Figure 7.3: Current Reduction Adjust Resistor Placement