HIMA F 3421 8-Channel Digital Output Module Safety-Related Discrete Unit

Technical Overview

The F 3421 (Part Number: F3421) is a high-performance digital output module engineered for the HIMA HIMatrix system, providing eight safety-related channels for industrial automation. This module is specifically designed to control safety-critical actuators, valves, and contactors in environments requiring SIL 3 compliance. It features advanced internal diagnostics and short-circuit protection, ensuring that the "safe state" is maintained even in the event of an external field fault.

Detailed Specifications

The following technical data outlines the electrical and mechanical performance of the F 3421 unit:

• Output Capacity: 8 Safety-related digital channels

• Nominal Voltage: 24 V DC

• Output Current: Up to 0.5 A per channel (short-circuit proof)

• Safety Integrity Level: Certified up to SIL 3 / PLe

• Switching Logic: High-side switching with integrated wire-breakage monitoring

• Galvanic Isolation: Safety isolation between the system bus and field level

• Current Consumption: Approximately 50 mA at 24 V DC (internal electronics)

• Dimensions: 2 cm x 18.8 cm x 12.8 cm

• Net Weight: 0.18 kg

• Manufacturing Origin: Germany

• Protection Class: IP20-rated for cabinet installation

Functional Logic and Protection

The F 3421 is built to handle the rigors of emergency shutdown (ESD) and Fire and Gas (F&G) systems. Key functional features include:

• Active Diagnostics: Continuous monitoring of the output stage for cross-circuit and external voltage interference.

• Failure Response: In the event of a logic error or communication loss, the module automatically forces all outputs to a de-energized "safe" state.

• Thermal Protection: Each channel is equipped with thermal shutdown capabilities to prevent module damage during overcurrent events.

Frequently Asked Questions

Does the F 3421 require external fusing for each channel?While the F3421 features electronic short-circuit protection, HIMA typically recommends external fusing for line protection depending on the cable cross-section and local safety regulations.

Can I parallel multiple outputs to increase the current load?Generally, safety modules like the F3421 are not designed for paralleling outputs to drive a single high-current load, as this can interfere with the diagnostic testing pulses used for safety monitoring.

Product Family Comparison

• F3421: 8 digital outputs, 0.5 A per channel, standard HIMatrix form factor.

• F3422: High-current variant often supporting up to 2 A per output for driving larger solenoids.

• F3221: Digital input counterpart used for signal acquisition from field switches.