Rockwell Automation 999 IMC S Class Compact Motion Controller (Cat. No. 4100-999-122) - Manual (Page 40)

3-10 Technical Overview
Publication 999-122 - January 1997
DH-485 Communication The IMC-S/23x communicates with other devices over DH-485 by
reading and writing data into and out of data files. Data from local files
(in the motion controller) is transferred to and from remote files (in
other devices). In the motion controller, up to 13 different local files of
five different types can be used. Each type of file contains a different
number of elements and is equivalent to a different SLC file type as
shown below.
Axis-Specific Discrete I/O Each axis of the IMC-S/23x has associated with it four
optically-isolated inputs which provide a direct interface for a home
switch, overtravel (positive and negative) switches, and a drive fault
signal (usually an output from the amplifier). In addition, a relay-
contact drive enable output is provided for each axis to enable and
disable the amplifier under program control. The four discrete inputs
are completely de-bounced and can be connected directly to limit
switches which operate on 24V DC. Inputs can be from mechanical
limit switches, proximity switches, or PLC outputs.
Each axis of the IMC-S/23x can be individually programmed to operate
with or without these discrete inputs enabled. If enabled, each discrete
input can be individually programmed to operate with normally open
(NO) or normally closed (NC) limit switch contacts.
Home Limit Switch Input
Home limit switches are used in conjunction with two of the four
programmable homing sequences. When a homing sequence is
enabled, the IMC-S/23x executes it under program control. See the
Setup section of this manual for a complete description of the available
homing sequences.
Overtravel Limit Switch Inputs
Overtravel limit switches can be used to enforce the mechanical safe
travel limits during machine operation. Assuming that the overtravel
function is enabled, the IMC-S/23x may be programmed to either
provide a status, disable the feedback loop, and deactivate the drive
enable output of the affected axis, or stop motion and decelerate the
axis to a stop when an overtravel limit switch is tripped.
IMC S Class DH-485 Local File Types
S Class
File Type
Elements Element
Numbers
Equivalent to
SLC File Type
Binary
Integer
Floating
ASCII
BCD Words/Bits
16-bit Values
Floating Point Values
Characters
BDC Values 0 - 1023
0 - 1023
0 - 511
0 - 2047
0 - 1023 B
N
F
A
D