Rockwell Automation 7000 PowerFlex Medium Voltage Air-Cooled (B Frame) Installation - ForGe Control - Manual (Page 58)

58 Rockwell Automation Publication 7000-IN007E-EN-P - June 2014
Chapter 3 Drive Installation
Power and Control Wiring Drive line-ups (i.e. drive and input starter) shipped in two or more sections for
ease of handling require reconnection for power and control wiring. After joining
the sections, reconnect the power and control wiring as shown in the schematic
drawings provided with the drive.
Control Cables
Locate control cable entry/exit near the terminal block 'TBC'. Route
connections along the empty side of the TBC terminals. These terminals accept a
maximum AWG #14 wire gauge. Connect the low voltage signals (includes
4...20 mA) using twisted shielded cable, with a minimum AWG #18 wire gauge.
(Based on using a W4 terminal block for customer connections, comparable wire
sizes would be 0.5...4 mm

as equivalent to #22-#10 AWG).
Two encoder inputs accommodate a quadrature encoder (senses motor
direction). The encoder power supply is isolated and provides 15V and a ground
reference. Many encoder outputs have an open collector output, which requires
an additional pull-up resistor to feed proper signals to the system logic. (Refer to
Torque Requirements for Threaded Fasteners on page 73 to see if one is
required).
Encoder Installation Guidelines
Common problems in an encoder’s signal transmission to the drive include signal
distortion and electrical noise. Either problem can result in a gain or loss of
encoder data counts (quadrature encoders) or corrupt positional data (absolute
encoders). This section provides general guidelines and recommended practices
for field-installed equipment, and applies to either encoder board and both
quadrature and absolute encoders.
Protection from Radiated and Conducted Noise
Take care when connecting and routing power and signal wiring on a machine or
system. Radiated noise from nearby relays, solenoids, transformers, non-linear
loads (such as motor drives) etc. can couple onto signal wires producing
undesired pulses. The encoder itself may also induce noise into adjacent signal
lines.
IMPORTANT Connect low voltage signals using twisted shielded cable, connecting the
shield at the signal source end only. Wrap the shield at the other end with
electrical tape and isolate it. Make connections as shown on the drawings
provided.