I/O modules

Product Overview

The GE HE693RTM705 functions as a master communication module for remote terminal unit applications in the Series 90-30 PLC family. This module enables reliable data exchange between the CPU and remote field devices using standard serial protocols. We engineered the HE693RTM705 to provide versatile communication capabilities for distributed automation and telemetry systems.

Technical Specifications

Key Features and Benefits

• Dual-Port Communication: The HE693RTM705 provides both RS-232 and RS-485 interfaces in a single module. You connect to local programming devices and remote field networks simultaneously without additional hardware.

• MODBUS Master Capability: This module operates as a MODBUS RTU master, reading data from up to 247 slave devices. Consequently, you integrate intelligent instruments, drives, and RTUs directly into the control system.

• CPU Compatibility: The module works with CPU331 and larger processors in the Series 90-30 family. Therefore, you add communication capability to existing systems without upgrading the main processor.

• Flexible Protocol Support: In addition to MODBUS, the HE693RTM705 supports GE SNP protocol and user-configurable serial I/O. You communicate with a wide range of devices using their native protocols.

• Robust Electrical Isolation: Optical isolation protects the PLC backplane from surges and ground loops on communication lines. This feature ensures reliable operation in electrically noisy industrial environments.

Detailed Functional Description

The primary function of the GE HE693RTM705 involves managing serial communication between the Series 90-30 CPU and external devices. Specifically, it acts as a MODBUS master, polling slave devices for process data and writing control values as required. The module handles all protocol details, including message formatting, error checking, and retransmission on failure. It then makes received data available to the CPU through shared memory, simplifying the control program. Furthermore, the module buffers data during CPU scan delays, ensuring no communication timeouts occur.

Communication Port Details

We designed the HE693RTM705 with two independent ports for maximum flexibility:

Each port independently configures for protocol, baud rate, and data format. You can operate one port as MODBUS master and the other as SNP slave simultaneously.

Protocol Support Details

The GE HE693RTM705 supports multiple protocols for diverse applications:

• MODBUS RTU Master: Reads/writes coils and registers from slave devices; supports function codes 1-6, 15, 16

• MODBUS RTU Slave: Allows external masters to access PLC memory

• SNP (Series Ninety Protocol): GE proprietary protocol for programming and HMI communication

• Serial I/O: User-definable protocol for custom devices using ASCII or binary formats

Installation and Configuration

Engineers install the HE693RTM705 in any I/O slot of a Series 90-30 rack. The process involves:

1. Inserting the module into the rack and securing with locking tab

2. Connecting Port 1 (RS-232) to programming device or HMI

3. Wiring Port 2 (RS-485) to field device network

4. Setting RS-485 termination switch if module sits at network end

5. Configuring communication parameters using Logicmaster or CIMPLICITY software

The module stores configuration in non-volatile memory within the CPU, not on the module itself.

Mechanical Details

The GE HE693RTM705 features the standard Series 90-30 form factor for easy installation. Its front panel provides:

• DB9 connector for RS-232 (Port 1)

• 5-position terminal block for RS-485 (Port 2)

• LED indicators for module status and port activity

• Label area for port identification

The module includes a metal shield for electromagnetic compatibility and meets industrial noise immunity standards.

Compatibility Information

The HE693RTM705 operates with the following GE systems:

• Series 90-30 CPUs 331, 340, 350, 360, and 363

• Series 90-30 expansion racks

• CIMPLICITY and Logicmaster programming software

• MODBUS networks with up to 247 slave devices

Common Industrial Applications

The GE HE693RTM705 provides essential communication for remote monitoring and control:

Why Choose This Module?

Selecting the GE HE693RTM705 means choosing a versatile communication solution for your Series 90-30 RTU system. You gain MODBUS master capability without programming complex protocol logic in ladder logic. The dual-port design allows simultaneous connection to local HMIs and remote device networks. With support for multiple protocols, you interface with a wide variety of field equipment using their native languages. The module works with existing CPU331 and larger processors, adding communication capability without costly upgrades. For Series 90-30 systems requiring robust serial communication, the HE693RTM705 delivers the performance and reliability you need.

Details