Figure 7.3 Current Reduction Adjust Resistor Placement - Intelligent Motion Systems IM805 Operating Instructions Manual

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 IM805 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 sys-
tem power efficiency.
The output current may be reduced to the level needed to maintain motor
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 dependant 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 mo-
tor 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 reduc-
tion adjust resistor (R
The current will be reduced aproximately 1.0 seconds after the rising edge
of the last step clock pulse. The value of R
= 500 x
R
Red
NOTE: Resistor leads should
be as short as possible to
minimize the amount of noise
coupled into the driver!
Figure 7.3: Current Reduction Adjust Resistor Placement
) and the value of the current adjust resistor (R
Red
I x I
Run Hold
( )
I - I
Run Hold
Current Adjust Resistor
1/8 W 1%W
IM805 Operating Instructions Revision R032306
is calculated as follows:
Red
I is the desired peak running
Run
current. Range 1.0 to 7A Peak
I is the desired peak holding
Hold
current. Range 0.5A to 7A Peak
Reduction Adjust Resistor
1/8 W 1%W
P2:2
P2:1
).
Adj
39