General Electric IC690ACC903 Series 90-70 RS-485 Port Isolator

Description

The General Electric IC690ACC903 is an RS-485 Port Isolator that adds opto-isolated signal channels between an RS-485 serial port and connected communication equipment on GE programmable controller networks. The IC690ACC903 replaces the earlier IC655CMM590 Isolated Repeater/Converter, commonly referred to as the "Brick," and provides 500 volts of isolation in a compact package that services the IC693 (Series 90-30), IC697 (Series 90-70), and IC200 (VersaMax) PLC product lines.

The IC690ACC903 connects directly to an RS-485 serial port, or through the short extender cable supplied with the unit for panel-mounted or space-constrained installations. A slide switch on top of the module selects single-drop (port-to-port) or multi-drop operating mode, allowing the Isolator to be deployed in point-to-point isolation links or in multi-device RS-485 networks with up to eight devices on a multidrop segment.

Internally, the IC690ACC903 isolates four signal channels (SD, RD, RTS, and CTS) using optical isolation and a 5V DC/DC converter for power isolation between the host port and the connected equipment. The module supports hot insertion into an existing communication channel and can also be configured for external power supply through a custom cable, maintaining communications continuity during a host system power cycle.

Features

• Four opto-isolated signal channels: SD, RD, RTS, and CTS
• 500 volts of isolation between the RS-485 host port and connected equipment
• Electrical compatibility with RS-485 (EIA-422/485 balanced line)
• Selectable single-drop (port-to-port) or multi-drop operation via slide switch
• Input termination consistent with standard serial channel requirements
• Integrated 5V DC/DC converter for power isolation
• Hot insertion supported into an existing communication channel
• Compact contoured enclosure for direct port mounting or panel mounting with the supplied extender cable

Applications

• Adding electrical isolation to RS-485 serial links on GE Series 90-30 (IC693), Series 90-70 (IC697), or VersaMax (IC200) PLC serial ports
• Point-to-point and multi-drop RS-485 communication networks requiring surge or ground-loop protection
• Panel-mounted installations where direct connection to the PLC serial port is obstructed by surrounding equipment
• Applications requiring externally powered isolation to maintain communications during PLC power cycling

Technical Specifications

Mechanical

Electrical

Connections / Interfaces

PL1 - 15-pin male D-connector (direct port mounting)

PL2 - 15-pin female D-connector (communication cable)

Note: Pin assignments are identical between PL1 and PL2, except that pin 4 on PL2 connects to the module ID resistor. To use the terminating resistor at pin 9, place a jumper wire from pin 9 to pin 10.

Installation Guidelines

1. Determine the mounting method: direct attachment to the PLC RS-485 serial port, or panel mounting using the extender cable supplied with the unit.
2. For direct attachment, connect the Isolator to the RS-485 serial port and secure it with the two supplied M3 connector thumbscrews, torqued to 8 in./lbs. (0.9 Newton-meter).
3. For panel mounting, secure the Isolator using two user-supplied #6-32 (4 mm) screws, torqued to 12 in./lbs. (1.4 Newton-meter).
4. Select single-drop (port-to-port) or multi-drop operating mode using the slide switch on the top of the module before connecting the communication cable.
5. In multi-drop configurations, install the terminating resistor jumper (pin 9 to pin 10) only at the first and last device on the bus, with a maximum of eight devices on a multidrop segment.
6. If external power is required to maintain communications during a host power cycle, wire +5V and GND through a custom external-power cable rather than relying on the host port supply, and do not daisy-chain +5VDC pins between devices.