Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive - Air-Cooled (A Frame) - Manual (Page 71)

Drive Installation 2-41
7000 “A” Frame 7000A-RM001A-EN-P – January 2011
• Unused Inputs
Not all inputs, in either the quadrature or absolute encoders, may be
necessary. For example, the absolute encoder can accept a 12bit
encoder but will work with a lower resolution. Likewise, quadrature
encoders may not utilize the Z track. The following should be used
for unused inputs:
1.
20B-ENC Board. Any unused input should be wired to the
encoder power rail. This also includes the B and B’ inputs if
using a pulse tachometer. Failure to do this will result in phase
loss warnings and improper operation of the encoder feedback
logic (i.e. missing counts).
2.
Universal Encode Interface. When used as a quadrature encoder
interface, the same rule applies as for the 20B-ENC Board.
When operating as an absolute encoder interface, the wiring of
unused inputs is dependent on the position of the POL_QRDNT
jumper. If the jumper is installed, then wire all unused inputs to
ENC PWR, otherwise use ENC COM.
Grounding Practices The purpose of grounding is to:
• provide for the safety of personnel
• limit dangerous voltages on exposed parts with respect to ground
• facilitate proper over current device operation under ground fault
conditions, and
• provide for electrical interference suppression
Generally, the means used for external grounding
of equipment should be in accordance with the
Canadian Electrical Code (CEC), C22.1 or the
National Electrical Code (NEC), NFPA 70 and
applicable local codes.
Refer to the grounding diagrams that follow for ground connections.
The drive’s main ground bus must be connected to the system
ground. This ground bus is the common ground point for all grounds
internal to the drive.
I M P O R T A N T I M P O R T A N T