©
National Instruments Corporation
19
nuDrive Accessory User Guide
The amplifier peak and continuous current limits and the current gain have
been factory set for 5 A continuous and 10 A peak current output. Verify
that these settings are appropriate for your application before powering
your motors.
Adjusting Current Gain and Current Limits
You can adjust the current gain and current limits by changing the values
of R6, R7, R40, and R42 on the servo amplifiers. The resistors are standard
1/4 W axial leaded type and are plugged into sockets on the PWM per axis
servo drives.
Note
Some components on your nuDrive are missing from their sockets. These
components were removed at the factory to configure the amplifier as a torque (current)
block.
Configure the current gain on the nuDrive so that the value of the maximum
command voltage, when multiplied by the gain, results in the value of the
maximum allowable peak current, as shown in Figure 18.
Calculate the gain using the following formula:
where Gain represents the gain value in amps/volt, I
peak
represents the
maximum allowable peak current, and V
max
represents the maximum
command voltage from your motion controller.
Note
±10 V is the maximum/minimum command voltage for National Instruments
motion controllers.
Once you have calculated your gain value, determine the resistor values for
R6 and R7 using the following formula:
where R
6,7
is the value for both resistor R6 and resistor R7 in k
Ω
.
After setting the gain value, you need to adjust the values of the R40 and
R42 resistors to configure your peak current limit and continuous current
limits.
Gain
I
peak
V
max
-----------
=
R
6 7
,
50
Gain
-------------
=
Summary of Contents for nuDrive 2CF-001
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