Rockwell Automation 57C419 5V-24V DC Input Module - Manual (Page 9)

2Ć1
2.0 MECHANICAL/ELECTRICAL
DESCRIPTION
The following is a description of the faceplate LEDs, field termination
connectors, and electrical characteristics of the field connections.
2.1 Mechanical Description
The input module is a printed circuit board assembly that plugs into
the backplane of the DCS 5000/AutoMax rack. It consists of a printed
circuit board, a faceplate, and a protective enclosure. The faceplate
contains tabs at the top and bottom to simplify removing the module
from the rack. Module dimensions are listed in Appendix A.
The faceplate of the module contains a female connector socket and
32 LED indicators that show the status of the inputs. Input signals are
brought into the module via a multiĆconductor cable (M/N 57C375;
see Appendix D). One end of this cable attaches to the faceplate
connector, while the other end of the cable has stakeĆon connectors
that attach to two 20 point terminal strips for easy field wiring.
On the back of the module are two edge connectors that attach to
the system backplane.
2.2 Electrical Description
The input module contains 32 input circuits for 5Ć24 volt logic signals.
Each group of four circuits shares a single isolated common. Input
signals have 5000 volt isolation to logic common. Refer to the block
diagram in Appendix B.
Each input circuit consists of a current limiting resistor, a zener diode
to control the switching level, an optical isolator, and a filter to
eliminate spurious signals. The input filter time constant is 0.7 msec
for the latching inputs (bits B17ĆB20) and 3.3 msec for all other
inputs. A circuit diagram is shown in figure 2.1.
Inputs connected to terminal strip connections B17, B18, B19, and
B20 can also be programmed to generate interrupts on positive or
negative transitions.