GB/Z 3836.37-2025Explosive atmospheres - Part 37: Equipment protection by 2-wire intrinsically safe ethernet concept (2-WISE) (English PDF)

3.2 Advanced physical layer; APL

A physical layer based on 10BASE-T1L.

3.6 Power source port

A port that provides DC power to the APL segment in addition to communication.

3.7 Power load port

A port that consumes DC power from the advanced physical layer (APL) segment in addition to communication.

3.8 Communication only port

A port that provides communication only during normal operation and does not provide or consume a large amount of DC power.

3.9 Auxiliary device port

A 2-WISE device port that provides functions other than communication.

NOTE: 2-WISE devices with auxiliary ports may include loads or introduce insertion losses for communication signals. Surge protectors are such devices.

3.10 APL segment

An interconnection of a power source port and a power load port, or two communication only ports, in a 2-WISE system.

4.1 General

2-WISE devices shall comply with the relevant requirements of GB/T 3836.4, except as modified in this document. 2-WISE devices shall be suitable for use in 2-WISE systems conforming to this document.

Each port shall comply with the requirements of 4.2, 4.3 or 4.4.

If there is any terminal network attached to the maximum output value permitted by 2-WISE within the 2-WISE power source port, power load port or communication only port, capacitance will be present at the port connection. When capacitance is protected by a series resistor with a minimum value of 90 ohm, the effective value of the capacitance shall not exceed 2.2 µF. When protected by a series resistor conforming to the requirements of GB/T 3836.4, other equivalent combinations of capacitance and resistance may be selected based on the permissible reduction in effective capacitance.

NOTE: the dielectric strength requirement for the insulation between the 2-WISE port terminals and the 2-WISE device rack or grounding component is the same as the dielectric strength requirement for the insulation between intrinsically safe circuits and electrical equipment racks or grounding components specified in GB/T 3836.4.

The electrical parameters of 2-WISE communication only ports connected to intrinsically safe systems shall conform to the values given in Table 2.

4.5 Simple Devices

The internal inductance Li and internal capacitance Ci of each simple device connected to the 2-WISE system shall respectively be less than 1 µH and 1 nF.

In addition to the marking requirements in Chapter 7, simple devices shall comply with all relevant requirements of this document and GB/T 3836.4.

5.1 General

A typical 2-WISE system consists of two 2-WISE ports connected to both ends of a cable, with a maximum of two 2-WISE devices with 2-WISE auxiliary devices between them. There are two different types of 2-WISE systems.

---Communication only systems; and ---Systems with power supply.

The common function is communication. Systems with power supply provide additional power in the following modes.

---The power source port provides DC power to the system, and the power load port consumes DC power from the system. The auxiliary device port may also consume DC power from the system.

---In communication only systems, DC power is not provided to the system through the 2- WISE connection; in this case, the 2-WISE device is always independently powered.

The communication only port shall not be connected to the power source port.

Simple devices conforming to 4.5 can be added to a 2-WISE system without modifying the system's safety assessment.

The total inductance and capacitance of all simple devices connected to the 2-WISE system shall not respectively exceed 10 µH and 5 nF.

NOTE 1: in accordance with 4.5, 2-WISE connectors or electromechanical switches are considered simple devices, but this does not affect the total inductance and capacitance.

NOTE 2: for functional reasons, the cable (terminated line) used to connect 2-WISE device and auxiliary device ports and connected in parallel with the 2-WISE system will be less than 1 m and is not considered part of the total cable length of the 2-WISE system.

5.2 Wiring System

The cables used in the 2-WISE system shall conform to the following parameters.

---Cable resistance Rc. 15 ohm/km ~ 150 ohm/km.

---Cable inductance Lc. 0.4 mH/km ~ 1 mH/km.

---Cable capacitance Cc. 45 nF/km ~ 200 nF/km.

NOTE 1: installation and structural requirements for individual cables and multi-core cables carrying multiple intrinsically safe circuits are specified in GB/T 3836.18.

NOTE 2: measurement of cable parameters is specified in GB/T 3836.18. […]