Rockwell Automation 57C421B Pulsetach Input Module/DCS 5000/AutoMax - Manual (Page 9)

2Ć1
2.0 MECHANICAL/ELECTRICAL
DESCRIPTION
The following is a description of the faceplate LEDs, field termination
connectors, and the electrical characteristics of the module.
2.1 Mechanical Description
The Pulsetach Input module is a printed circuit board assembly that
plugs into the backplane of an AutoMaxr rack. It consists of the
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 back of the module contains two edge connectors
that attach to the system backplane.
The faceplate of the module contains six LED module status
indicators and a female connector socket. Input signals are brought
into the module via a multiĆconductor cable (M/N 57C372). One end
of this cable has a plug that mates with the faceplate connector
while the other end of the cable has stakeĆon connectors that are
attached to a terminal strip for convenient field wiring connections.
The module's faceplate connector socket and the cable's plug have
provisions for keying the cable to its respective module to prevent
reĆinsertion of the cable into the wrong module.
The six LEDs on the faceplate of the module are shown in figure 2.1.
The first three LEDs are labeled COUNT STOP", LATCH", and
CLEAR". These LEDs correspond to the module's three external
digital inputs. They turn on whenever their corresponding input is
true (high) regardless of whether the input has been enabled on the
module (see register 6).
The next two LEDs are labeled FORWARD" and REVERSE". These
LEDs, when on, indicate whether the counter is counting pulses in
the forward direction or in the reverse direction.
The last LED is labeled CCLK OK". When this LED is on, it indicates
that the constant clock (CCLK) signal is present on the backplane.