Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C-Frame) - ForGe Control - Manual (Page 358)

358 Rockwell Automation Publication 7000L-UM301D-EN-P - June 2014
Chapter 5 Component Definition and Maintenance
The isolated Process Output is configured as 4-20 mA. The three isolated process
inputs are individually configurable for either a range of -10/0/+10V or 4-20 mA
(Refer to Programming Manual).
The following information will show the connections for each.
Current Loop Transmitter The current loop transmitter will transmit a 4-20mA output to an external
receiver. The loop compliance on the transmitter is 12.5V. Loop compliance is
the maximum voltage at which a transmitter can generate to achieve the
maximum current and is usually a function of the power supply voltage.
Therefore, the PowerFlex 7000 “C” Frame transmitter can drive a receiver with
an input resistance up to 625 ohms.
Figure 294 shows a block diagram of the
transmitter.
Figure 294 - Process Loop Transmitter Block Diagram
This type of transmitter is known as a 4-wire transmitter, and will “sink” current
from a receiver. The receiver is connected by two wires only from pins 20
(+ connection) and either pins 18, 19, 21 (- connection).
The recommended connection is shown above. The type of shielded cable used is
application specific and is determined by the length of the run, the characteristic
impedance and the frequency content of the signal.
Isolated Process Receiver
These inputs are individually configurable to accept either a -10/0/+10V input
signal or a 4-20 mA signal. When configured for voltage input, each channel has
an input impedance of 75 Kohms. When used as a current loop input, the
transmitter must have a minimum loop compliance of 2 volts to satisfy the 100
5V
DSP
FPGA
#
ŀ
Isolated
DC/DC
Converter
+15V
+15V
D/A
Current
Boost
Optical
Interface
20
18
19
21
IFM