HIMA F7126 24V to 5V DC-DC Converter Power Supply for Safety Rack

The HIMA F7126 is a rack-mounted, galvanically isolated DC/DC safety power supply module designed for the central rack of HIMA H41q / H51q safety-related control systems (PES). It converts a 24 V DC primary supply into a tightly regulated 5 V DC system voltage that powers the central processing units, communication modules, and I/O logic circuits inside the safety instrumented system (SIS) rack.
Built for high-availability process safety applications, the F7126 integrates input/output isolation, overvoltage protection, current limiting, and short-circuit-proof output. It supports parallel redundant operation together with the HIMA F 7131 power supply monitoring module, making it a core power component for ESD, BMS, and FGS cabinets in oil & gas, petrochemical, and power generation environments.

🔷Key Specifications

Specification	Detail
Brand	HIMA
Model	F 7126
Module Type	Isolated DC/DC Safety Power Supply Module
Compatible System	HIMA PES H41q / H51q Safety Control Systems
Input Voltage	24 V DC (range –15 % to +20 %)
Output Voltage	5 V DC, stepless adjustable; factory preset 5.4 V DC ±0.025 V
Rated Output Current	10 A continuous
Current Limiting	Approx. 13 A
Overvoltage Protection	6.5 V DC ±0.5 V
Isolation	Galvanic isolation between 24 V input and 5 V output
Conversion Efficiency	≥ 77 %
Front Panel	Test socket + voltage trim potentiometer
Redundancy	Supports parallel redundant operation (voltage balance ≤ 0.025 V between modules)
Rack Width	8 TE (standard F-series plug-in format)
Operating Temp.	–20 °C to +60 °C
Storage Temp.	–40 °C to +85 °C
Humidity	5 %–95 % RH, non-condensing
Protection	Overvoltage, overcurrent, short-circuit proof
Safety Integrity	SIL 3 capable (IEC 61508 / IEC 61511 context)
EMC Compliance	VDE 0871 / 0877 Class B
Country of Origin	Germany

🔨Product Overview

The HIMA F7126 is the dedicated 24 VDC-to-5 VDC converter module for HIMA safety racks. Unlike a commercial off-the-shelf power supply, it is qualified for use in safety-related automation architectures where deterministic fault behavior, electrical isolation, and redundant availability are mandatory.

Installed in the central rack backplane, the F7126:

Supplies regulated 5 V DC to H41q/H51q central modules and I/O carriers
Electrically isolates field-side 24 V DC from sensitive 5 V logic circuits
Detects overvoltage, overload, and short-circuit conditions
Supports load-sharing redundancy with other F7126 modules
Reports supply status through the F 7131 monitoring module

Because the module is part of the safety power architecture, a single F7126 failure in a redundant setup does not disable the safety function. The remaining module continues to carry the 5 V backplane load while the fault is reported to the controller.

1️⃣Core Functions

1. Regulated 5 V DC Output for Safety Logic

Converts 24 V DC panel supply into stable 5 V DC for CPUs, coprocessors (e.g. F 8621A), communication interfaces, and I/O electronics.

2. Galvanic Input/Output Isolation

Prevents fault propagation from the 24 V field power domain into the 5 V safety logic domain, reducing common-mode failure risk.

3. Redundant Parallel Operation

Multiple F7126 modules can operate in parallel. The front-panel potentiometer allows fine adjustment so that output-voltage deviation between units stays within ≤ 0.025 V, ensuring balanced load sharing.

4. Built-in Protection

Overvoltage clamp at 6.5 V ±0.5 V
Current limit near 13 A
Short-circuit-proof output stage
Primary side 6.3 A slow-blow fuse

5. On-site Calibration & Diagnostics

Front test jack enables quick voltage verification; trim pot allows commissioning adjustment without removing the module from the rack.

2️⃣Typical Applications

Refinery and petrochemical ESD (Emergency Shutdown) systems
Boiler and turbine BMS (Burner Management System) racks
Oil & gas FGS (Fire & Gas) safety systems
Power plant safety interlock cabinets
Process industry SIS using HIMA H41q / H51q controllers
Redundant safety PLC backplanes requiring SIL 3 power integrity

3️⃣System Context in H41q / H51q Racks

In an H51q central rack, the F7126 works together with:

F 7131 – power supply monitoring module (battery-backed supervision, fault signaling)
F 8621A – optional coprocessor / RS485 communication module
Central units and I/O modules on the 5 V backplane

For extended 5 V current demand, HIMA offers the B 9361 assembly kit, which houses up to three F7126 modules in an N+1 redundant configuration with decoupling, fusing, and fan monitoring.

4️⃣Installation & Maintenance Notes

Mount only in designated F-series rack slots of H41q/H51q systems.
Before parallel redundancy, trim output voltage so deviation between modules is ≤ 0.025 V.
Use the front test socket to verify 5 V DC during commissioning and periodic inspection.
Replace only with identical F7126 hardware; follow site safety and HIMA documentation.
In redundant configurations, a failed unit can be isolated by the decoupling diodes, but replacement should follow approved lockout/tagout or hot-spare procedures.

HIMA F7126 24V to 5V DC-DC Converter Power Supply for Safety Rack