Rockwell Automation 7000A PowerFlex Medium Voltage Drive (A-Frame) - Classic Control - Manual (Page 391)

Component Definition and Maintenance 6-87
7000 “A” Frame 7000A-UM150F-EN-P –June 2013
Analog Inputs and Outputs
The PowerFlex 7000 “A” Frame offers one isolated process current loop
transmitter and one isolated process current loop receiver, embedded into
the control. These are accessible on the CIB.
Each of these can be configured independently as either 0-20mA or
4-20mA. (Refer to Programming Manual).
The following information will show the connections for each.
Current Loop Transmitter
The current loop transmitter will transmit either 0-20mA or 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 “A” Frame
transmitter can drive a receiver with an input resistance up to 625 ohms.
The figure below shows a block diagram of the transmitter.
DSP
FPGA
Optical
Interface
D/A
Current
Boost
Isolated
DC/DC
Converter
+15V
+5V
1
2
3
4
J4A
+15V
DSP
FPGA
Optical
Interface
D/A
Current
Boost
Isolated
DC/DC
Converter
+15V
+5V
1
2
3
4
J4A
+15V
Figure 6.67 – 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 1 (+ connection) and either pins 2, 3, 4 (- connection).
The recommended connection is shown below. 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.