SMART I/O User’s Manual
©1996 PEP Modular Computers GmbH
October 01, 1996
Page 6 - 17
6
Chapter 6 Communications Modules
†
All outputs are referenced to the common Ext. Vcc
6.2 SM-SSI
6.2.1 Introduction
The SM-SSI is an optoisolated single-channel, 24-bit RS422 interface for
absolute encoders. Configurable data input together with flexibility afforded
by software configurable encoder types transforms this SMART Module into
an intelligent interface suitable for the most demanding applications. Data
flow is indicated by the presence of two red LEDs on the front panel.
6.2.2 Specifications
Isolation
2.5 kV optoisolated from the system
Input
1 optoisolated SSI channel, 24-bit binary or Gray code
(software configurable), RS422 type
2 optoisolated 24V DC digital inputs for common GND and
End-of-Range switches with readback and IRQ support
Output†
2 optoisolated 24V DC/300mA digital outputs for Encoder
Reset and Encoder Direction
1 optoisolated 24V DC/300mA digital output for Match
SSI Interface
None, Even or Odd (software configurable), Data, Parity
Software configurable (data bits, parity) encoder type
Software detection of line break
SSI defined, RS422 type Clock Output
62.5, 125, 250 or 500kHz (programmable) Tx. Pulse Freq.
Data flow controlled by software and indicated by LED status
Up to 24-bit Compare Register with pass-through compare
Interrupt, software and LED control of Match Result
Front Panel
2 Red LEDs indicating MATCH and data conversation
Ext. Vcc
24V DC (
±
5%)
Power Cons.
325 mW (min.), 375mW (max.)
Temperature Range Standard (0˚C to +70˚C), Extended/Storage (-40˚C to +85˚C)
Operating Humidity
0% to 95% (non-condensing)
