Technique, A/B technique concept | Siemens EN 50295 instruction

AS-Interface

A/B technique

■Overview

Previously 31 nodes	Slave 1	Slave 31

with A/B slaves max. 62 nodes:	Slave 1A	Slave 1B	Slave 31A	Slave 31B

Mixed operation also permissible:	Slave 1	Slave 2A	Slave 2B	Slave 31

The A/B technique concept

6 The AS-Interface specification 2.1 allows a doubling of network stations from 31 to 62. The 31 addresses that can be assigned in an AS-Interface network can be split into two mutually inde- pendent sub-addresses, e.g. in 1A and 1B.

If this is utilized for all 31 slaves, up to 62 slaves can be con- nected within an AS-Interface network. The so-called A/B slaves can each have up to four inputs and three outputs.

G_IK10_XX_20020

Another new feature of the new AS-Interface specification V2.1 is integrated analog value transfer. In this case, integrated means that no special function blocks are required in order to access the analog values. Accessing data is therefore just as easy in the case of analog values as it is with digital values. In- tegrated analog value transfer can be used with analog slaves that support Proifiles 7.3 and 7.4.

	Slave type	Number of slaves	Number of inputs	Number of outputs
AS-Interface standard	Standard slave	Up to 31	31 x 4 = 124	31 x 4 = 124

AS-Interface version 2.1	A/B slave	Up to 62	62 x 4 = 248	62 x 3 = 186
AS-Interface master		Communication cycle

To operate A/B slaves in an AS-Interface network, master mod- ules working according to the specification 2.1 must also be used. The A/B technique is supported by the SIMATIC S7 masters and the DP/AS-Interface links from Siemens. To masters that do not support specification 2.1, only standard and A slaves can be connected.

The sub-address of A/B slaves is set to “A” by default.

Masters and slaves that are already working to the new specifi- cation are identified accordingly in the catalog.

Addressing A/B slaves

A/B slaves can be addressed like standard slaves via all com- mercial AS-Interface addressing units conforming to specifica- tion 2.1. AS-Interface addressing units that do not conform to the new specification 2.1 can readdress A/B slaves only as A slaves.

As far as addressing is concerned, an analog slave is like a stan- dard slave. Up to 31 analog slaves can therefore be operated in one AS-Interface segment.

Standard slaves are polled in every cycle (max. cycle time: 5 ms).

If only an A or B slave is installed at an address, this slave is also polled in every cycle (max. cycle time: 5 ms).

If an A/B slave pair is installed at an address, slave A is polled in one cycle, slave B in the next (max. cycle time: 10 ms).

If only standard and/or A slaves are installed in a network, the cycle time is the same as for standard masters (max. cycle time:

5 ms).

■Benefits

• Lower costs for masters and power supply units

• Enhanced decentralization in installations with numerous, widely distributed signals

• Existing AS-Interface systems can be expanded further

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Siemens IK PI · 2004

EN 50295 specifications

Siemens EN 50295 is emerging as a pivotal standard in the domain of electrical safety and design, particularly relevant for the electrical industry and equipment manufacturing sectors. Primarily, this European Norm is geared towards ensuring the safety of electrical systems used in dry environments, which is essential for various industrial applications.

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Another characteristic of the EN 50295 standard is its adaptability. The framework it provides can be customized depending on specific industry needs, making it versatile across various sectors such as manufacturing, construction, and transportation. This adaptability ensures that businesses can maintain high safety standards while still allowing room for innovation and modern practices.

In summary, Siemens EN 50295 presents a well-rounded approach to enhancing safety, reliability, and sustainability in electrical systems. Its features and characteristics are set to guide industries in making informed decisions regarding electrical configuration, ultimately fostering a safer and more efficient working environment. The incorporation of emerging technologies ensures that the standard remains relevant in a fast-evolving technological landscape, proving to be an invaluable asset for manufacturers and service providers alike.

Siemens EN 50295 manual Technique, A/B technique concept, AS-Interface master Communication cycle

Models: EN 50295