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):