Product details

A program is a sequence of instructions, and executing a program is to execute instructions one by one according to the sequence of instructions. Once the program is installed in the main memory, the CPU can automatically complete the task of accessing instructions from the main and executing instructions.

CPU includes arithmetic logic component, register component, arithmetic unit and control component.

PLC and DCS system in common

①DCS: Distributed control systems (distributedcontrol systems).

PLC: Programmable Logic Controller (PLC). Both have different emphasis and are advanced.

②DCS focuses more on the process control field (such as chemical, smelting, pharmaceutical, etc.) is mainly the monitoring and adjustment control of some field parameters, while PLC focuses on logic control (machining class). Of course, the current PLC can also deal with process control problems well, but there is no DCS professional.

(3) If the simulation quantity is greater than 100 points, DCS is generally used; If the analog quantity is within 100 points, PLC is generally used.

DCS is a "distributed control system", and PLC is just a control "device", the two are the difference between "system" and "device". The system can realize the functions and coordination of any device, and the PLC device only realizes the functions of this unit.

The DCS network is the central nervous system of the whole system, DCS system usually uses the international standard protocol TCP/IP. It is a safe and reliable double redundancy high-speed communication network, the system is more extensible and open. Because the PLC basically works for a single small system, when communicating with other PLC or host computer, the network form used is basically a single network structure, and the network protocol is often inconsistent with international standards.

All I/O modules of DCS system are equipped with CPU, which can realize the acquisition and output signal quality judgment and scalar transformation, fault charging, random replacement. The PLC module is just a simple electrical converter, there is no intelligent chip, and the corresponding unit is all paralyzed after the failure.

What is an I/O unit?

Typically, a process control station consists of several racks, each of which can hold a certain number of modules. The rack where the CPU is located is called the CPU unit. There can only be one CPU unit in the same process station. The other racks that are used only for placing I/O modules are I/O units.

ABB series of products