5466-316 Internal Relay

In order to complete the control strategy, in order to replace the relay, so that the user and so on to complete the ladder diagram of the control system similar to the relay line, 5466-316 compiled a set of control algorithm function blocks (or subroutines), called the instruction system, solidified in the repository ROM, the user can be invoked in the preparation of the application program. The instruction system can be roughly divided into two categories, namely, basic instructions and extended instructions.

The 5466-316 provides physical layer RS232/422/485 interfaces on the basis of the original CPU template, and gradually adds various communication interfaces, and provides a complete communication network. Due to the recent rapid development of data communication technology, users of openness requirements are very strong, fieldbus technology and Ethernet technology is also synchronised with the development of the PLC composition of the PCS system than the openness of the DCS is in a slightly better status quo. At present Rockwell AB has formed a multi-layer structure system, namely, Ether Net, Control Net, Device Net and Asi and other field buses (the original DH + network is also compatible). Siemens in the Profibus-DP communication network and Profibus-FMS network outside the proposed S7 Routing network, that is, Profibus-DP and Industrial Enternet two-tier structure. The network is still developing, our country should have been active posture into it.

Subdivision of the general PLC instruction system are: basic instructions, timer / counter instructions, shift instructions, transfer instructions, compare instructions, conversion instructions, BCD arithmetic instructions, binary arithmetic instructions, incremental / decremental instructions, logic instructions, special arithmetic instructions, etc., which are mostly similar to assembly language. In addition, PLC also improves sufficient internal resources such as timers, counters, internal relays, registers and storage areas, which brings great convenience for programming.