Description
Overview
The Honeywell 621-9928R is a specialized Serial Link Selector (SLS) module engineered for IPC 620 and IPC 621 systems. It manages redundant serial communication channels, automatically or manually switching between primary and backup links to maintain uninterrupted data flow. With support for RS-232 and RS-422 protocols, robust optical isolation, and visual diagnostics, this module is critical for fault-tolerant industrial networks.
Key Features
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Redundant Serial Link Management: Seamlessly switches between dual serial inputs for continuous connectivity
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Protocol Support: Compatible with RS-232 and RS-422 communication standards
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Flexible Switching Modes: Manual, remote command, or automatic selection
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Diagnostic Indicators: Front panel LEDs display active link status and fault conditions
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Industrial-Grade Reliability: Optical isolation and EMI-resistant design ensure safe operation in harsh environments
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Compact Modular Form Factor: Double-wide module designed for rack installation in IPC 620/621 I/O slots
Technical Specifications
| Specification |
Details |
| Model Number |
621-9928R |
| Product Type |
Serial Link Selector Module (SLS) |
| Supported Protocols |
RS-232, RS-422 |
| Input Links |
2 serial inputs |
| Output Links |
1 selectable output |
| Switching Logic |
Manual, remote, or automatic |
| Baud Rate Range |
300 bps – 115.2 kbps |
| Isolation |
Optical on all serial channels |
| Front Panel Indicators |
LED for Link 1 active, Link 2 active, fault |
| Connections |
2 × 12-position input blocks, 1 × 12-position output block |
| Power Supply |
5 VDC from system backplane |
| Dimensions |
130 × 35 × 110 mm |
| Weight |
0.75 kg |
| Operating Temperature |
0°C to 60°C |
| Storage Temperature |
–40°C to +85°C |
| Mounting |
Double-wide module, slots B & C of I/O card file |
Functional Description
The 621-9928R continuously monitors two serial links and automatically selects the operational channel if a fault is detected. This ensures uninterrupted communication for operator stations, engineering workstations, and external system interfaces in IPC 620/621 distributed control systems.
Applications
Ideal for process automation, energy management, and industrial control systems where redundancy and network reliability are essential. It supports seamless data transmission in oil & gas, chemical, and power generation plants.
FAQ
Q: What is the main purpose of the 621-9928R module?
A: To provide fault-tolerant serial communication by selecting between redundant RS-232/RS-422 links.
Q: Can it operate in harsh industrial conditions?
A: Yes, with optical isolation, EMI resistance, and robust industrial design.
Q: Is it compatible with automatic switching setups?
A: Yes, it supports manual, remote, and automatic switching modes for flexible operation.
