TRICONEX PM6301A

Description

Before making a decision on the system control scheme, it is necessary to understand the control requirements of the controlled object in detail, so as to decide whether to select PLC for control.

TRICONEX PM6301A

It is necessary to use PLC control when the logic relationship of the control system is relatively complex (requiring a large number of intermediate relays, time relays, counters, etc.), the process flow and product modification are frequent, data processing and information management (including data calculation, analog control, PID adjustment, etc.) are required, the system requires high reliability and stability, and the factory automation networking is prepared.

TRICONEX PM6301A
At present, many manufacturers at home and abroad have provided various series of PLC products with different functions, making users dazzled and at a loss. Therefore, only by comprehensively weighing the advantages and disadvantages and reasonably selecting the model can we achieve the goal of economic and practical use. Generally, the model selection should be based on the purpose of meeting the functional requirements of the system, and should not be blindly greedy to avoid wasting investment and equipment resources. The selection of model can be considered from the following aspects.

TRICONEX PM6301A

Selection of input/output points

TRICONEX PM6301A

Blind selection of models with more points will cause certain waste.

The total number of I/O points of the control system shall be cleared first, and then the required number of PLC points shall be determined after the reserve amount of 15~20% of the actual total number of points is reserved (leaving room for system modification, etc.).

TRICONEX PM6301A
In addition, it should be noted that some high-density input point modules have restrictions on the number of input points connected at the same time. Generally, the number of input points connected at the same time should not exceed 60% of the total input points; The driving capacity (A/point) of each output point of PLC is also limited, and the output current of some PLCs varies with the applied load voltage; Generally, the allowable output current of PLC decreases with the increase of ambient temperature. These problems should be taken into account when selecting models.

The output points of PLC can be divided into common point, group and isolated connection methods. Different voltage types and voltage levels can be used between each group of isolated output points, but the average price of this PLC is higher. If there is no need for isolation between output signals, PLC of the first two output modes shall be selected.