Device for intrinsically safe redundant current supply of field devices

Abstract

A device is provided for intrinsically safe redundant current supply of field devices (3) with a common current-limiting resistor (21) in the mesh of the field device and with redundant current supply units (11, 12). In the system, a current sensor (22) can be provided in the mesh of the field device, the output signal of whichis connected to devices for controlling current or active current limiters (112,122) in the redundant current supply units.

Description

[0001] technology area [0002] The invention relates to a system for the reliable and redundant power supply of field devices themselves in automation technology in explosion-protected areas. Background technique [0003] A system of the described type has at least two supply circuits for supplying a current supply / voltage supply and a protective device for its own reliable power limitation of the current supplied by the supply circuits to consumers in the Ex area, wherein the The supply circuits described above as part of the protective device each have means for regulating and / or limiting the current. [0004] Such systems are known and used in installations in which parts of the operating equipment are operated in explosion-proof areas. The power supply unit can be integrated into the I / O module and can be regarded as a link between the external computing unit of the programmable-memory control device and the sensors and / or actuators in the Ex area. [0005] Devices oper...

AI Technical Summary

Problems solved by technology

Disadvantageously, a switchover procedure to the redundant transmitter supply unit is required in the event of failure of the supplied measuring transducer supply unit

[0014] Finally, when redundantly supplying the connected field devices via a common single current-limiting resistor, it is conceivable that the loop current in the supply circuit can be limited to permissible values ​​even during redundant supply and that the field devices In the event of a permissible short-circuit in the conductor loops on the side, the power loss at the individual current-limiting resistors in the redundant power supply leads to an impermissible overload of the purely resistive current-limiting device in the power supply

Images