Rockwell Automation 57C411 Resolver Input Module - Manual (Page 9)

2Ć1
2.0 Mechanical/Electrical
Description
The following is a description of the faceplate LEDs, field termination
connectors, andelectrical characteristics of the fieldconnections.
2.1 Mechanical Description
The input module is a printedcircuit boardassembly that plugs into
the backplane of the DCS 5000 rack. It consists of the printedcircuit
board, a faceplate, and a protective enclosure. The faceplate
contains tabs at the top andbottom 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
5 LED indicators for module status, including one light that indicates
when the boardis operational (on) or malfunctioning (off).
Input signals are brought into the module via a multiconductor cable
(M/N 57C373; see Appendix D). One end of this cable attaches to the
faceplate connector, while the other endof the cable has stakeĆon
connectors that attach to a terminal boardfor easy fieldwiring. The
faceplate connector socket andcable plug are keyedto prevent the
cable from being pluggedinto the wrong module.
On the back of the module are two edge connectors that attach to
the system backplane.
2.2 Electrical Description
The input module contains a tracking resolverĆtoĆdigital converter that
produces a 12Ćbit digital number proportional to one electrical
revolution of a resolver. The digital position may be sampled in one of
two ways. The most common methodis to specify the sampling
period. The period may range from a low of 500 microseconds to a
high of 32.7675 seconds, in increments of 500 microseconds.
The secondmethodis to sample the position when an external event
occurs. This methodis useful when it is necessary to synchronize the
DCS 5000 with the occurrence of a particular event. Using an
external strobe input is a simple methodof synchronizing your
application software to the exact position of an object when an
external event occurs. See figure 2.1 for details about the electrical
characteristics of the external strobe input circuit. Because of the high
input impedance of the strobe input, the device driving the input
must have low leakage. See figure 2.2.
The module can be programmed to generate an interrupt whenever it
does a periodic sample. This mode allows you to synchronize task
execution with the conversion of new data. The converted data will
be latchedwhen the interrupt is generated.
The module contains a 2Ćbit electronic counter that can count a total
of 4 electrical resolver revolutions. This 2Ćbit counter is containedin
the most significant two bits of resolver position, registers 0 and1.
This counter is reset whenever power is turnedon to the system or a
boardreset commandoccurs.