Rockwell Automation 8510 AC Spindle Drive System User Manual - Manual (Page 61)

Interface Signal Descriptions
Chapter 7
7-57
The Enable Torque programmable parameter will determine whether or not
holding torque is available from the motor when the Drive Enable input is
On. If the parameter is set to “Without Run,” holding torque is available as
soon as the Drive Ready output turns On. If the parameter is set to “With
Run,” either the Forward Run or Reverse Run inputs must be On before
holding torque will be available.
The Drive Enable input can not be applied until the drive has completed
the initial power-on diagnostics and the Hard Fault output has been turned
On to indicate that no control malfunctions were detected. If this input is
turned On before the power-on diagnostics are completed, it will be ig-
nored.
Important: The Drive Enable input must not be used by itself to provide a
regenerative “emergency” stopping capability since an electronic malfunc-
tion could potentially prevent the drive from stopping. To achieve regener-
ative braking in an “emergency” stop situation, the following circuit that
combines the Drive Enable and Coast to Stop input functions is suggested.
A single output from the “emergency” stop circuit of the CNC or control
station connects to the Drive Enable input of the drive (see Figure 7.1).
This same output is also connected to a user supplied relay with an
electro-mechanical or pneumatic controlled time delayed dropout. A
contact from the time delayed relay is connected in series with the Coast to
Stop input of the drive.
Removing Drive Enable will cause the drive to regenerate to a stop and
drop the contactor when zero speed is reached. When the time delay relay
opens at the end of the time delay, the contact breaks the coil circuit of the
contactor. The drive is then placed in a state in which no silicon circuitry is
depended upon for maintaining the power off state.
If a drive malfunction occurs, causing it to ignore the disable signal, the
drive will only run for the time delay setting of the relay. At the end of the
timeout, the motor contactor will be opened by passive circuitry, causing
the system to coast to a stop.
Important: The magnitude of the time delay is application dependent and
must be carefully chosen. The delay should be sufficient to allow the drive
to stop the motor from maximum speed with the maximum expected load
inertia. However, excessive time delays could pose a safety hazard in the
event of an electronic malfunction.