Rockwell Automation 57C422B 2 Axis Servo Module - Manual (Page 13)

MECHANICAL / ELECTRICAL DESCRIPTION 2-3
Signals are brought into the module via a multi-conductor
cable (M/N 57C377). One end of this cable attaches to the
faceplate connector, while the other end of the cable
attaches to a terminal board for easy wiring.
On the back of the module are two edge connectors that
attach to the system backplane.
2.2 Electrical Description
The module contains an 80186 microprocessor, local RAM,
and EPROM for the axis software. It also contains a dual port
memory organized as 4k x 16 for transferring data to/from
the module and the application software. Refer to the block
diagram in Appendix B.
This module also contains a watchdog timer that is used to
detect a processor failure. The processor is required to keep
resetting the watchdog before it expires. If the watchdog
expires, the processor will be halted, the green LED on the
faceplate of the module will be turned off, and dual port
memory will be locked so that the module can no longer be
accessed by application software.
M/N 57C422A and later versions of the module support
level-sensitive hardware interrupts. Interrupts are used to
trigger execution of some part of an application task and are
implemented using BASIC language hardware EVENT
statements. See Section 4.49 for more information.
Each of the two axes contain the necessary circuitry for two
encoders. One encoder is used to provide feedback to the
axis. The other encoder can be used when gearing or cam
mode is selected to provide a reference for that same axis.
Each encoder input channel has the necessary circuitry for
an “A” channel, "B" channel, and "Z" channel. The encoder
input circuit is designed for 5 volt differential signals. A single
external power supply is required to power all of the
encoders connected to the module. Refer to figure 2.2 for a
typical encoder input circuit.