HIMA H41q/H51q F 3331 8-Channel Safety Output Module

Product Overview

The F 3331 (F3331) is a high-reliability, 8-fold safety-related output module engineered by HIMA for use in critical control systems requiring Requirement Class AK 1 through 6. This module is a cornerstone in Safety Instrumented Systems (SIS) within the chemical processing, subsea, and pharmaceutical industries, where safe isolation and integrated shutdown capabilities are paramount. The F 3331 supports resistive and inductive loads up to 500 mA (12 W) and is specifically designed to prevent unintended output signals in the event of an L- supply break. By providing continuous automated testing and line monitoring, it ensures that your safety loops remain functional, significantly reducing the Risk Priority Number (RPN) of your automated assets.

Technical Configuration

The F 3331 is designed with a "testable" architecture, meaning it performs self-diagnostics without interrupting the process logic. Its safety DNA is built around three core pillars:

• Integrated Safety Shutdown: Hardware-level circuitry ensures the module can reach a de-energized state upon demand or internal fault detection.

• Comprehensive Test Routines: The module executes a "walking-bit test" to check for cross-talking and switching capability, alongside a read-back feature that monitors output signals (0-signal threshold ≤ 6.5 V).

• Line Monitoring: The module actively supervises the connection to the field device, detecting short circuits (tripping between 0.75 and 1.5 A) and line breaks (monitoring current between 0.5 and 9.5 mA).

Technical Specifications

Technical FAQs

How does the module handle a "0 signal" fault?

The read-back operating point for a 0-signal is ≤ 6.5 V. It is important to note that if a fault causes the voltage to rise but stay below this 6.5 V threshold, the system will not detect it as a high-level fault.

What happens if there is a break in the L- supply?

The F 3331 is designed so that no output signal is possible if the L- supply is broken, ensuring a fail-safe condition.

Is there a limit to the length of the field wiring?

Yes, the admissible line resistance (combined in and out) is a maximum of 11 Ohm. Exceeding this resistance can interfere with the module's ability to accurately monitor line breaks and short circuits.

Engineering & Installation Guide

• Load Balancing and Heat Management: While the module is rated for 500 mA per channel, the total power dissipation at 24 VDC can reach 180 mA plus the combined load. Ensure the cabinet has adequate convection cooling, as excessive ambient heat (above 60 deg C) can shift component tolerances and affect the undervoltage tripping point (standardly ≤ 16 V).

• Inductive Load Protection: For inductive loads, although the module is rated for 12 W, we recommend installing external flyback diodes at the load side for high-cycle applications to further protect the integrated safety shutdown circuitry from back-EMF spikes.

• Test Signal Transparency: The test signal duration is extremely short (max. 200 microseconds). While this is transparent to most industrial actuators and lamps, ensure that any downstream high-speed electronic interfaces are compatible with this transient diagnostic pulse to avoid "flicker" or false triggering.