Honeywell 621-9940C Serial I/O Module

The Honeywell 621-9940C is a robust Serial Input/Output (I/O) module within the Honeywell PLC-5 family of programmable logic controllers. This module is designed to facilitate communication with and control of various serial devices, such as printers, barcode scanners, and other industrial equipment. It offers excellent flexibility with support for both RS-232 and RS-485 serial communication protocols.

Key Features and Technical Specifications

Parameter	Details
Model	621-9940C
Manufacturer	Honeywell
Product Type	Serial I/O Module
Compatibility	PLC-5 family of programmable logic controllers
Serial Communication Protocols	RS-232, RS-485
Duplex Operation	Half-duplex, Full-duplex
Baud Rates	300 to 19,200 bps
Data Bits	7 or 8
Parity Bits	None, Even, Odd
Stop Bits	1 or 2
Number of Serial Ports	12
Buffering	1024 bytes per port
Error Detection	CRC-16, Parity
Modbus Support	Master, Slave
Isolated Ports	Yes
Operating Temperature	-25°C to 85°C
Conformal Coating	Yes
Dimensions	1.5 inches x 4 inches x 1 inch
Weight	0.88 kg

Performance and Functionality

The Honeywell 621-9940C module ensures seamless communication between your PLC-5 system and serial devices, enhancing the functionality of industrial processes. It supports both RS-232 and RS-485 communication protocols, making it highly adaptable to various setups. You can choose between half-duplex or full-duplex operation, offering versatility depending on your system’s requirements.

This module can operate at a wide range of baud rates, from 300 bps to 19,200 bps, ensuring compatibility with various devices and communication standards. It supports 7 or 8 data bits, with selectable parity options (None, Even, Odd), and allows configuration for 1 or 2 stop bits, providing flexible communication settings tailored to your needs.

Additionally, the 621-9940C features 12 serial ports, each with 1024 bytes of buffering to handle large amounts of data. It also integrates error detection mechanisms such as CRC-16 and Parity to ensure reliable communication. The module supports Modbus communication in Master and Slave configurations, making it ideal for control systems that require complex network communication.

Compact and Durable Design

The Honeywell 621-9940C module has a compact design, measuring only 1.5 inches x 4 inches x 1 inch. Despite its small size, it is highly durable and operates within a wide temperature range of -25°C to 85°C, making it suitable for use in harsh industrial environments. The module is also coated with conformal coating, providing additional protection against moisture and contaminants.

Weighing only 0.88 kg, the 621-9940C module is lightweight and easy to install, helping to streamline system integration without adding unnecessary bulk.