Chapter 3
Signal Connections
©
National Instruments Corporation
3-7
NI 951x User Manual
Servo Command Signals
Drive Command Output
The Drive Command output on the servo drive interface modules provide
a ±10 V analog output. The Drive Command output features software
configurable torque limits and voltage offset.
Drive Command COM
To help keep digital noise separate from the analog output, there is a
separate return connection. Use this reference connection as the reference
for the Drive Command output when connecting to servo drives instead of
using COM (digital I/O reference).
Additional Drive Signals
Drive Enable
Use the Drive Enable output on the NI 951x module to control the enable
function of a drive. The enable input on the drive must be active for the
drive to acknowledge commands from the module. The Drive Enable signal
is active during normal operation and deactivated upon a fault or error
condition. Refer to the
NI SoftMotion Module
book of the
LabVIEW Help
for a list of faults, errors, and other conditions that deactivate the Drive
Enable output.
Caution
National Instruments strongly recommends using Drive Enable for personal
safety, as well as to protect the motion system.
Drive Enable Output Circuit
You can use software to enable and disable the Drive Enable output and to
configure the active state of the Drive Enable output to on or off. Refer to
the drive documentation to determine the active state of the enable input on
the drive. The Drive Enable output type can be configured in software for
sinking or sourcing. If the drive has a sinking enable input, configure the
output type for the Drive Enable circuit for sourcing. Conversely, if the
drive has a sourcing enable input, configure the output type for the Drive
Enable circuit for sinking.
Caution
Only connect the Drive Enable output to +5 V input circuitry when the output is
configured for sinking.