AB 1794-OB8 FLEX I/O Digital DC Output Modules

AB 1794-OB8 FLEX I/O Digital DC Output Modules

Installation requirements: For use in industrial environments of pollution class 2, overvoltage category II, at an altitude of up to 2000 metres above sea level, as Group 1, Class A industrial equipment. Installation in a flame-retardant, tool-accessible enclosure is required to meet EMC and safety requirements. Use zinc-plated yellow chrome steel DIN rails for grounding and avoid using other rail materials that may cause poor grounding.

Approved for use in hazardous areas

North America: Some modules (1794-OB8, 1794-OB8EP, 1794-OB16, 1794-OB16P) are approved for use in hazardous areas in North America. The products are labelled with a temperature code, and when combining devices, attention should be paid to the overall temperature code and local regulatory review. When operating in a hazardous area, it is strictly prohibited to disconnect or connect the device with electricity, and operations such as battery replacement should be performed in a non-hazardous area.

Europe: Some modules (1794-OB8, 1794-OB8EP, 1794-OB16, 1794-OB16P) are certified for use in potentially explosive atmospheres by Zone 2 Europe. When in use the equipment has to fulfil specific conditions, such as protection against UV rays, avoidance of voltage overruns, etc.

Module Installation

Preparation for Installation: The module should be mounted on a 1794 series terminal block, ensuring that no debris falls into the module prior to installation and that plugging or unplugging the module while it is energised may be hazardous.

AB  1794-OB8 FLEX I/O Digital DC Output Modules

Installation Procedure: Turn the key switch to position 2, make sure the Flexbus connector is fully extended, insert the module and align it with the notch for a secure installation.

Wiring Methods: Wiring methods vary between module models (1794-OB8, 1794-OB8EP, 1794-OB16, 1794-OB16P, 1794-OB32P). Output, power, and common wires need to be connected according to specific rules, and the power supply can be daisy-chained, and the total current must not exceed 10A.

Module Configuration

1794 - OB8EP Module: Configured by setting bits in the configuration word, fault bits can be programmed to detect faults, and faults can be reset by pushbuttons, programming, or cycling the backplane power.

Other modules (1794-OB8, 1794-OB16, 1794-OB16P, 1794-OB32P): Configuration by setting the bits in the configuration word (word 3).

Note

Zone Classification and Equipment Suitability: 1794-OB8 is suitable for use in North American Class I Division 2 Groups A, B, C, and D hazardous areas and European Zone 2 hazardous areas, but cannot be used in other hazardous area classifications. Hazardous area temperature codes are marked on the product nameplate. When using the product in a system combination, the most unfavourable temperature code (the lowest ‘T’ number) must be used to determine the overall system temperature code, and the combination of equipment must be reviewed by the local regulatory agency.

ELECTRICAL SAFETY OPERATIONS: Disconnecting equipment or connections while energised is strictly prohibited, and before operating in a hazardous area, you must either disconnect the power supply or ensure that the area is free of hazards. Plugging and unplugging modules under electrical power can cause arcing, which may result in an explosion, as well as wear and tear of the module and connector contacts, which can interfere with the normal operation of the equipment. When used in hazardous areas, prevent the rated voltage from exceeding the specified value due to transient disturbances, e.g. in European 

Zone 2 environments, take measures to ensure that transient disturbances do not cause the voltage to exceed 40% of the rated value.

Installation and earthing of the device: The device must be installed in a compliant enclosure with a minimum IP54 protection rating (required for European Zone 2 environments), with the interior accessible only by means of a tool, and with suitable flame retardancy to prevent the spread of flame. Use zinc-plated yellow chrome steel DIN rails for earthing, avoiding corrosive, oxidising or poorly conductive rail materials such as aluminium or plastic to prevent poor earthing. Securely fasten DIN rails to the mounting surface at intervals of approximately 200mm (7.8in.) and use end anchors where appropriate.

Component and connection management: Avoid changing components as this may affect the suitability of the equipment for use in hazardous areas. Ensure that all external connections are securely fastened by screws, slide latches, threaded connectors, etc.

Troubleshooting and maintenance: The 1794 - OB8 module outputs are not fused and it is recommended that they are protected externally by a SAN - O MQ4 - 800mA fuse. In the event of a module fault, for the 1794-OB8EP module, the fault can be reset by pressing the fault reset button on the front of the module, toggling the output reset bit (Write 1, Bit 08), or cycling the backplane power.