DEIF BRW-1 Marine Instruments: Installation and Calibration Guide for Offshore Bridge Indicators

2. Precautions for sealing protection and anti-static measures

Silicone seal protection: Special silicone sealing materials are used between the shell and panel, as well as between the glass and the frame of BRW-1, to achieve IP66 protection. During installation, disassembly, or subsequent maintenance, extra care must be taken to avoid damaging these seals. Any scratches or deformations may cause water tightness failure.

Electrostatic discharge protection: Unlike other precision electronic devices, BRW-1 is designed with electrostatic protection in mind, and its instructions clearly state that "no special ESD protection measures are required during installation". This simplifies the on-site installation process, but despite this, following basic electrostatic discharge prevention measures (such as avoiding direct contact with circuit boards in dry environments) is still a good engineering practice.

Electrical connection: precise wiring ensures reliable operation

The electrical connection of BRW-1 involves power supply, signal input, and additional functions. Correct wiring is the guarantee for accurate instrument indication and long-term stability.

1. Wiring terminals and operating space

The wiring terminals of the instrument are hidden behind the dial and need to be disassembled before they can be accessed:

Disassembly steps: Use a standard 4mm hex wrench to disassemble the potentiometer panel located in front of the dial. After disassembly, the internal wiring terminal block can be seen. During this process, it is also important to be careful not to damage the silicone sealing ring between the panel and the shell.

Applicable wire diameter: Screw terminals are suitable for multi strand flexible wires ranging from 0.2 to 2.5 mm ², or single strand hard wires up to 4 mm ². It is recommended to use multiple strands of soft wire and match it with a suitable wire nose to obtain more reliable electrical connections and better anti vibration performance.

2. Definition of power and signal terminals

Lighting power supply (terminals 5 and 6):

Under standard configuration, the lighting power supply is 24V AC/DC, connected to terminals 5 (positive/phase) and 6 (negative/medium) labeled "SUPERLY ILLUM.

High voltage configuration: For BRW-1 with an ordered 110/220V AC built-in transformer version, the lighting power supply cannot be connected to terminals 5 and 6, but should be directly connected to the dedicated terminals on the transformer (marked as 0V, 110V, 220V). This configuration also allows for the simultaneous connection of 24V DC as a backup power source, which automatically switches when the main power supply loses power, ensuring that critical indicators are never interrupted. This is a highly valuable feature.

Measurement signal input (terminals 1 and 2):

The measurement signal of the instrument (such as 4-20mA current signal from the speed transmitter or 0-1mA DC signal) should be connected to terminal 1 (positive pole) and terminal 2 (negative pole).

Grounding protection (EARTH terminal):

The terminal marked with "EARTH" must be reliably connected to the ship's grounding. This is not only a requirement of safety regulations (to prevent electric shock), but also an important measure to ensure measurement accuracy. Good grounding can shield external electromagnetic interference (EMI) and prevent stray currents from the ship from affecting instrument readings.

3. Engineering application of "through terminal"

BRW-1 is equipped with a set of auxiliary wiring points called "FEED-THROUGH TERMINALS" (through terminals). These terminals are connected in parallel with the main circuit and can be easily used in series to provide power to other adjacent instruments without the need for additional junction boxes or branch cables. This design reduces the number of cables and simplifies the wiring inside the bridge control console, reflecting DEIF's engineering wisdom in details.

4. Cable entrance

Two PG 13.5 cable sealing connectors are provided at the bottom of the instrument housing (optional with one PG 21 connector). PG 13.5 is suitable for cables with an outer diameter of 7.5/10/12.5mm, while PG 21 is suitable for cables with an outer diameter of 10/13/16/19mm. Choosing the correct sealing joint and adapting the outer diameter of the cable is crucial for maintaining the IP66 protection level.

On site calibration and scale replacement: customization and maintenance

The flexibility of BRW-1 is not only reflected in the ordering options, but also in the on-site adjustment and maintenance capabilities. Among them, the replacement of the dial is a typical task that engineers may encounter in project changes or instrument spare parts management.

1. Range calibration (maximum adjustment)

There is a potentiometer labeled "MAX. ADJ" between the two connectors on the front of the instrument panel.

Function: This potentiometer allows for adjusting the deflection angle of the instrument within a range of ± 10% of full scale. This function is mainly used to fine tune and match the scale of the indicator with the output of the actual sensor or transmitter on site, such as compensating for small losses in the signal transmission line.