KONGSBERG DZ-110/U transmitter safety barrier unit

KONGSBERG DZ-110/U transmitter safety barrier unit

Product positioning

DZ-110/U is a single channel parallel diode type safety isolation barrier designed specifically for installation in hazardous areas with two-wire 4-20mA transmitters. Unlike traditional Zener safety barriers, it integrates active circuits that not only achieve energy limitation, but also have signal amplification and precise replication functions, ensuring a strict proportional relationship between the dangerous side transmitter current and the safe side output current.

This unit is designed to be compact and can be mounted on TS-32 or TS-35 DIN rails, suitable for high-density installation of control room cabinets. The blue terminals clearly indicate the intrinsic safety side for easy on-site identification and wiring.

Deep analysis of working principle

The core innovation of DZ-110/U lies in the collaborative work of its current mirror amplifier and active current limiting circuit.

Breaking through traditional limitations

Traditional Zener safety barriers rely on Zener diodes and current limiting resistors to passively limit energy. When the dangerous side is short circuited, the fuse may melt, causing signal interruption. DZ-110/U solves this problem through active circuits.

Current mirror technology

A precision current mirror amplifier is integrated inside the isolation gate. Its working principle is as follows:

Dangerous side signal reception: The 4-20mA current generated by the dangerous area transmitter flows through the internal sampling resistor.

Accurate replication: The amplifier takes the current signal as input and generates a completely equal current output on the safety side, which is transmitted to the analog input channel of the monitoring system.

Electrical isolation: Although DZ-110/U does not use transformer or optocoupler isolation (belonging to the Zener gate type), functional safety isolation is achieved through voltage regulation and current limitation.

Dual protection mechanism

Zener diode clamp: A Zener diode connected in parallel on the safety side continuously monitors the voltage. When a fault overvoltage occurs, the diode conducts, limiting the dangerous side voltage to below 25.2V (Uo).

Active current limiting: This is the outstanding advantage of DZ-110/U. Traditional Zener barriers rely on fuses during short circuits, while the active current limiting circuit built into DZ-110/U actively intervenes when overcurrent is detected, limiting the current to a safe value (116mA, Io) to prevent the fuse from melting, thus avoiding the need to replace the safety barrier due to a single short circuit. This greatly improves the availability of the system.

Through this design, DZ-110/U ensures that the hazardous area will not receive ignition energy under any fault, while also ensuring the continuity and accuracy of signal transmission.

Installation specifications and special conditions

Installation location

DZ-110/U must be installed in a secure area cabinet, usually located in the control room or processing cabinet. The final installation must meet the following special conditions to maintain explosion-proof integrity:

Safety distance: The wiring distance between intrinsic safety circuits and non intrinsic safety circuits should be kept at least 50mm.

Cabinet protection: The protection level of the installed cabinet should reach at least IP22 (to prevent finger contact and vertical dripping), and specific requirements can be adjusted according to the actual installation environment.

Environmental temperature: The environmental temperature range is limited to -20 ° C to+70 ° C (Ta).

Grounding requirement: A grounding busbar must be installed on the intrinsic safety side of the safety barrier. Terminal 3 of each safety barrier must be connected to the grounding busbar through a cable of at least 1.5mm ².

Terminal function

Terminals 4 and 5/6 (blue): Connect the two-wire 4-20mA transmitter in the hazardous area to form an intrinsic safety circuit.

Terminals 2 and 3: Connect the analog input channel of the monitoring system in the safe area.

Terminal 6: Grounding terminal, connected to the intrinsic safety grounding busbar (used in conjunction with Terminal 3).

Mechanical Installation

DZ-110/U is designed for installing guide rails on TS-32 or TS-35 (in accordance with DIN46277), and is fixed by clamping. It is recommended to use end stops at both ends of the guide rail to prevent the unit from sliding.

Technical Specifications

power supply

24 VDC nominal (± 0.5V)

signal interface

4-20 mA (hazardous area transmitter input)

4-20 mA (safe area monitoring system output)

environmental conditions

Working temperature: -20 ° C to+70 ° C

Storage temperature: -25 ° C to+70 ° C

Relative humidity: maximum 75% (no condensation)

mechanical parameters

Dimensions: 12.5 x 114.5 x 99.0 mm (width x height x depth) * (Note: Based on DZ-120 and so on, not explicitly listed in the document, but similar in appearance)*

Protection level: IP20

Weight: Approximately 0.1 kg

Terminal capacity: 2.5 mm ²

Security data (entity parameters)

To ensure the correct selection and safe use by system designers, DZ-110/U provides the following key safety parameters (based on EN/IEC 60079-11):

Parameter numerical description

Um 250 VAC maximum safe voltage (maximum non intrinsic safety voltage that the terminal block can withstand)

Uo 25.2 VDC maximum output voltage (open circuit voltage)

Io 116 mA maximum output current (short-circuit current)

Po 0.73 W maximum output power

Co 107 nF maximum external allowable capacitance (distributed capacitance connecting hazardous side cables and instruments)

Lo 2.6 mH maximum allowable external inductance (distributed inductance connecting hazardous side cables and instruments)

Lo/Ro 48.8 μ H/Ω maximum ratio of inductance to resistance

Important: The total capacitance of cables and instruments connecting hazardous areas must not exceed Co, and the total inductance must not exceed Lo, otherwise it may store excessive energy and compromise intrinsic safety. Compared with DZ-120, the Co of DZ-110/U is slightly higher (107nF vs 95nF) and the Lo is slightly lower (2.6mH vs 2.8mH), which needs to be selected according to the on-site cable parameters during design.

Certification and Standards

DZ-110/U has passed strict explosion-proof certification and classification society type approval, ensuring its applicability to various types of ships and marine engineering worldwide.

Explosion-proof certification

ATEX: Compliant with EU Directive 2014/34/EU

IECEx: IECEx PRE 16.0020 (inferred based on model)

Explosion proof mark: II (1) G [Ex ia Ga] IIC

II: Equipment group (non mining)

(1) G: Associated equipment, can be installed in safe areas, used for G-class (gas) hazardous areas

[Ex ia Ga] IIC: Intrinsic safety level ia, applicable to the IIC gas group (the most flammable gases, such as hydrogen and acetylene)

Applicable standard

EN 60079-0/IEC 60079-0 (General Requirements)

EN 60079-11/IEC 60079-11 (Intrinsic Safety)

Classification society approval

The document clearly states that DZ-110/U has obtained type approval from the following classification societies:

BV (French Classification Society)

LRS (Lloyd's Register of Shipping)

Note: Other classification societies such as DNV-GL, ABS, CCS, etc. may be covered by similar models. Please consult Kongsberg for details.

Application scenarios

Ship liquid tank monitoring

In the tanks of oil tankers and chemical tankers (Zone 1/0), pressure, temperature, or liquid level transmitters are connected to the K-Chief or K-Gauge monitoring system in the control room through DZ-110/U. Current mirror technology ensures that signals are transmitted over long distances without distortion, and active current limiting prevents downtime and replacement due to occasional short circuits.

offshore platform

The transmitter signal in the platform process area needs to be transmitted to the central control room 100 meters away. The high-precision replication capability of DZ-110/U ensures the accuracy of analog control.

FPSO and Drilling Ship

Frequent power fluctuations and complex electromagnetic environments pose higher requirements for safety barriers. The stable voltage design and anti-interference ability of DZ-110/U ensure the stable operation of the system.

Chemical plant renovation project

Due to its compatibility with TS-32/35 rails and a width of only 12.5mm, DZ-110/U is highly suitable for adding intrinsic safety circuits to existing control cabinets without the need for large-scale modifications.

Core strengths

Accurate signal replication: The current mirror amplifier ensures better transmission accuracy of 4-20mA signals than traditional Zener gates, making it particularly suitable for applications that require high measurement accuracy.

High availability: Active current limiting prevents fuses from melting in the event of a short circuit, allowing for normal operation without the need to replace safety barriers, significantly reducing maintenance costs.

Flexible installation: compatible with TS-32 and TS-35 rails, suitable for different cabinet configurations.

Compact design: 12.5mm width, can accommodate more channels in limited space.

Comprehensive certification: recognized by ATEX, IECEx, and mainstream classification societies, meeting global ship and ocean engineering compliance requirements.

Compatible with Kongsberg system: seamlessly integrated with monitoring systems such as K-Chief and K-Gauge, plug and play.

Comparison with DZ-120

Characteristics: DZ-120 Zener safety barrier, DZ-110/U transmitter isolation barrier

Core function: Passive energy limiting, active current mirroring, and energy limiting

Signal transmission is directly amplified and accurately replicated through resistors

Short circuit protection fuse is active current limiting when blown, but not blown

Maintenance cost: After a short circuit, it needs to be replaced and automatically restored

Applicable scenarios: General 4-20mA high-precision/high availability requirements

Safety precautions

All installation and maintenance operations must follow the safety guidelines in document 373874 K-Gauge Ex I Safety Instructions. It is strictly prohibited to connect or disconnect hazardous area wiring while it is live. The grounding system must be reliable, and the grounding resistance should comply with relevant standards.