Rockwell Automation 20G PowerFlex 750-Series AC Drives User Manual
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Rockwell Automation Publication 750-RM002B-EN-P - September 2013
127
Feedback and I/O
Chapter 2
DI PHdwr OvrTrvl, DI NHdwr OvrTrvl
These digital input functions are used to trigger a Positive Hardware Over-travel
and/or a Negative Hardware Over-travel. The resulting action is to immediately
fault and produce zero torque. After the drive is stopped, the condition needs to
be cleared and the fault needs to be reset. The drive restarts (if given a new start
command), and continues operation. It follows any speed reference, position
reference, or torque reference. The drive’s direction is not modified or limited
after the restart. This function is usually used with a limit switch in a position
beyond the “End Limit,” as an extra safety limit to prevent torque from damaging
the machine in an over-travel situation.
Status
For the PowerFlex 753 main control board Digital Inputs (Di) 0, 1, and 2, P220
[Digital In Sts] Bits 0, 1 and 2 represents its respective inputs status. For the
PowerFlex 755 main control board Digital Inputs (Di) 0, P220 [Digital In Sts]
Bit 0 represents its respective digital input status. For the PowerFlex 750-Series
Option Module Digital Inputs (Di) 0, 1, 2, 3, 4, and 5, P1 [Dig In Sts] Bits 0, 1, 2,
3, 4, and 5 represents its respective digital input status. When the bit associated
with the digital input is on, depicted by a 1, this means that the drive recognizes
that the digital input is on. When the bit associated with the digital input is off,
represented by a 0, this means that the drive recognizes that the digital input is
off.
Configuration Conflicts
If you configure the digital inputs so that one or more selections conflict with
each other, one of the digital input configuration alarms is asserted. As long as the
Digital Input Conflict exists, the drive will not start. These alarms are
automatically cleared by the drive as soon as the parameters are changed to
remove the conflicts. These are examples of configurations that cause an alarm:
•
Configuring both the “Start” input function and the “Run Forward” input
function at the same time. “Start” is used only in “3-wire” Start mode, and
“Run Forward” is used only in “2-wire” Run mode, therefore, do not
configured at the same time.
•
Configuring the same toggle input function (for instance “Fwd Reverse”)
to more than one physical digital input simultaneously.
These alarms, called Type 2 Alarms, are different from other alarms in that it is
not possible to start the drive while the alarm is active. It is possible for any of
these alarms to occur while the drive is running, because all digital input
configuration parameters can be changed only while the drive is stopped.
Whenever one or more of these alarms is present, the drive ready status becomes
“not ready” and the HIM displays a conflict message. In addition, the drive status
light flashes yellow. Refer to the PowerFlex 750-Series Programming Manual,
publicatio
ete list of Type 2 Alarms.