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 妥思空调末端系列 |
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欧文托普阀门系列 |
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霍尼韦尔楼宇自控 |
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| as-i-system-描述和功能 |
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the as interface is the standardised (en 50295, iec 62026-2), open, non-proprietary bus system for the lowest field level of automation technology. the as interface serves to provide the most cost-effective means of connecting sensors and actuators to a higher-level controller while also functioning as an autonomous bus solution with the aim of reducing costs.
in order to enable compatibility among components from many different manufacturers in a single system, eleven renowned companies from the field of sensor and actuator technology formed a consortium in 1990 with the aim of developing a standard bus system.
as-interface-association
in the course of opening up the system to establish a general industrial standard, the "verein zur förderung busfähiger interfaces für sensoren und aktuatoren e.v." (as interface association) was founded back in 1991.
the as interface association is responsible for implementing the specifications developed by the as interface consortium, standardising the system on an international level, certifying products and carrying out ongoing development of the as interface.
the association now has over 250 members worldwide.
all products are tested and certified, prior to receiving the as interface logo.
what does as mean?
as is the abbreviation for actuator sensor.
the as interface is thus the actuator-sensor interface.
benefits of the as interface
the as interface sets new technological standards in comparison to previous bus systems. this entails economic advantages for the user with regard to planning, commissioning and maintenance of the system.
the as interface reduces the scope of wiring.
it offers an alternative to the cable harness. the necessary scope of wiring and cabling is drastically reduced, as the conventional parallel wiring between each individual component and the control cabinet is no longer necessary. this eliminates a broad scope of terminals, i/o cards of the programmable controller and cabling. the control cabinet volume and installation times are reduced substantially. the as interface merely requires a standard 2-wire line, which is installed in a tree structure through the system to the components.
the as interface distributes the available intelligence.
practicians have long recognised the advantages of decentralised automation. the trend towards ever larger, higher-capacity controllers to control a system on a centralised basis, which prevailed until several years ago, has now given way to a trend towards distributed solutions.
immediate local processing of important functions is performed by a small decentralised controller. only very few important items of information are transferred to a central master computer.
the advantages of such solutions are self-evident:
- shorter, less complex programmes, facilitating the commissioning of system components
- reduced down-times; the system continues to run without any restrictions, in the event of the failure of individual stations
- shorter cable links, data interchange between the controllers via bus systems
- simpler, faster installation and expansion.
the as interface saves operating costs.
use of the as interface drastically reduces the time required for maintenance, resetting, troubleshooting, etc. faults are quickly located and functional testing of the system or system components can be carried out on a decentralised basis.
expansion capability
- additional as interfaces can be incorporated at any point in the system.
- modular design.
- the as interface is open for innovations, guaranteeing compatibility with future requirements.
key data
topology
tree structure (also contains lines, etc.)
bus medium
unshielded two-wire cable for data and energy supply to the users (24 v dc, typically 200 ma per slave, e.g. 8 a per bus line).
cable length
100 m, extension via repeaters possible.
number of slaves 31 per as interface line
number of as interface lines as required, according to connection medium, e.g. up to 124 with rs485.
number of users combinations of up to 31 intelligent or 124 binary users per bus line.
access method master-slave, single master mode.
messaging single-address calling by master with direct reply from slave.
addressing fixed, unique address in the slave. addressing via master possible.
cycle time max. 5 ms.
master services
cyclic data interchange with all slaves; cyclic data interchange with host; non-cyclic output of parameters.
management functions initialisation of the as interface network; identification of bus users; master fault diagnosis and signalling; readdressing of replacement slaves. |
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风口