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Description
Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | 621-9939C |
| Manufacturer | Honeywell International Inc. |
| Product Type | Serial Link Module / Serial Communication Interface |
| System Compatibility | Experion PKS C200/C300; UDC 3300/3500; IPC 620 Series-1-5-8 |
| Communication Channels | 2 Independent Serial Ports (Channel A and B)-1 |
| Electrical Interfaces | RS-232, RS-422, RS-485 (Software Configurable)-1-2-3 |
| Supported Protocols | Modbus RTU (Master/Slave), DF1 Full-Duplex, DH-485, ASCII, Honeywell Peer Protocol, Custom Character Protocols-1-5 |
| Data Transfer Rate | 110 bps to 115.2 kbps (Software Configurable)-1-3 |
| Connector Type | 9-Pin D-Sub Female (per channel); Terminal Block for RS-485-1-5 |
| Operating Voltage | 20-60 V DC (Redundant Input Option); or 24V DC / 115V AC (Varies by Configuration)-1-2-7 |
| Power Consumption | Less than 5 W-3-11 |
| Operating Temperature | 0°C to +60°C (Standard)-1-5 |
| Storage Temperature | -40°C to +85°C-1-3 |
| Humidity | 5% to 95% RH, Non-Condensing |
| Dimensions | 100 x 50 x 30 mm (Approx., varies by configuration)-2-10 |
| Weight | 0.07 – 0.25 kg (Approx., varies by configuration)-2-3-7 |
| Maximum Nodes per Network | Up to 32 Devices on RS-485 Bus (with Unique Station Addresses)-5 |
| Termination | 120 Ohm Terminating Resistor Required at Bus Ends-5-8 |
| Configuration Software | Experion PKS Control Builder; Controller Front Panel-1-5 |
| Agency Approvals | UL, CE, CSA (Varies by Configuration)-7-11 |
Main Features and Advantages
Intelligent protocol conversion and dual-channel design: The Honeywell 621-9939C features two independent serial communication channels that can be configured to support different protocols and devices simultaneously-1. Each channel can operate at baud rates ranging from 110 bps to 115.2 kbps, providing the flexibility to connect diverse field devices including smart instruments, PLCs, weigh scales, barcode readers, and printers-1-4. The 621-9939C supports Modbus RTU as a master or slave, DF1 full-duplex for Allen-Bradley PLC integration, DH-485 for legacy networks, ASCII for simple device communication, and custom character protocols for specialized applications-1. This protocol versatility ensures that the Honeywell 621-9939C can serve as a universal serial gateway for virtually any serial device found in industrial environments.
Deep integration with Honeywell control systems: Unlike generic serial converters, the 621-9939C is deeply integrated into the Honeywell Experion PKS architecture-1. Configuration is performed using the standard Experion Control Builder, allowing serial data to be mapped directly into the controller’s database as native process variables-1. This eliminates the need for custom programming or complex data mapping, significantly reducing engineering effort and commissioning time. For UDC controller applications, the Honeywell 621-9939C enables legacy single-loop controllers to participate in a networked control strategy, providing centralized monitoring, setpoint adjustment, and data logging capabilities that were previously unavailable-5.
Robust design for industrial environments: The 621-9939C is engineered with high-quality components and subjected to stringent quality testing to ensure reliable operation in demanding industrial conditions-2-7. The module supports redundant power inputs on select configurations, providing enhanced reliability for critical applications where uninterrupted communication is essential-1. With a wide operating temperature range and protection against electrical noise on serial lines, the Honeywell 621-9939C maintains stable communication even in harsh factory floor environments.
Asynchronous operation with dedicated processor: Each 621-9939C contains its own processor and data table, enabling it to manage serial I/O data transfer asynchronously from the main controller processor-8. This architecture ensures that serial communication tasks do not impact the controller’s scan cycle or real-time control performance. When multiple 621-9939C modules are installed (up to two per system), the communication load is distributed, providing enhanced throughput and reliability for large-scale serial integration projects-8.
