Today, industrial automation devices need to process more data than ever before. The traditional implementation only focuses on the data needed for the actual processing task. Today’s devices need to handle more auxiliary information, such as configuration, diagnosis, alarm report, parameterization, etc., and modern communication systems are required to handle this information demand at different levels. In an industrial environment, lossless data communication is a key requirement because real-time processes are controlled by such data. In contrast, office / standard Internet communication has no such strict requirements. If the data is lost, it will be sent again. In industrial applications, retransmission is not an option because there is not enough time.

The scalable communication system that can meet all the needs of today is actuator sensor interface version 5 (asi-5). It supports this kind of real-time information processing, meets the reliability of traditional systems and improves the cycle time performance. As asi-5 is a true bus system, it provides great flexibility in wiring installation, thus reducing the overall system cost. Risa’s asi4u-v5 solution provides asi-5 with a multi-in-one system solution, ensuring the simplest integration option. Asi-5 can be enabled in all modes defined in the asi-5 specification.

Asi-5 is a true bus system, which means that up to 96 devices can exist on the same cable.

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Figure 1:asi system

The transmission technology uses four phase shift keying (QPSK) as the modulation scheme, and uses orthogonal frequency division multiplexing (OFDM) for multi carrier modulation (up to 154 carriers). Each of these carriers has a channel that transmits 20 bits of data in a 1.2ms period.

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Figure 2: excellent EMC reliability

A mechanism has been established to ensure reliable communication:

Every 20 bits are protected by cyclic redundancy check (CRC), so errors can be effectively identified.

Each process data is transmitted on three channels at the same time. The receiver must receive the same data on at least two channels to identify the process data as effective (2oo3 protection).

Another safety measure is that each symbol is sent twice in succession to prevent short-term electromagnetic interference. Therefore, three different methods can be used to protect data transmission from external interference. In a word, stable data transmission can be achieved even under adverse transmission conditions.

Using these mechanisms, we can ensure that all data can reach the destination without error in the harsh industrial environment.

Asi-5 has a wide range of functions to support industrial 4.0 applications. With the asi4u-v5 component solution provided by Renesas, the integration workload of asi-5 interface can be minimized.

Reviewed by: Guoting

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