Basic rules for reading and interpreting control panels

Its characteristic sign (=).

• It provides us with the relationship that exists between a certain number of elements with respect to their situation or position in the scheme.
• It can serve as an identification sign that indicates the position of a certain element of a complete team.
• This block should be used when, in the installation of, for example, an automation panel, there are several systems or groups of equipment and each of them consists in turn of several units or pieces of equipment.

For example:

• Direct starter group (system) consisting of several motor protection units.
• Heating resistance group (system) consisting of several radiators (units).

Block 2: (Location on the plan)

• Its characteristic sign (+).
• It provides us with the location of an element for quick identification of the place it occupies, among numerous elements with multiple uses of equal or similar presentation, of an important or complex set.
• The code of signs identifying the situation can be based on a sequence of successive numbers or on its coordinates, so that there is no ambiguity.

Block 3: (Identification Block)

This section is the most important and is sufficient in most cases. It consists of 3 parts:

• The class: It refers to the element, regardless of its function. It is represented by a letter. Each class, and therefore each letter, represents a family of elements, with the element symbol used allowing us to distinguish between the different members of that family.
• The number: The numbering is chosen according to the circuit's needs, that is, the number of devices used, and can be any natural number starting from one. The numbering does not need to be in a continuous sequence. To facilitate reading, groups of numbers or groups of elements can be assigned.
• The functionThis refers to the role or function that the element performs in the circuit, regardless of the type of element it is. It is represented by a letter.

Code to form part 3 of the identification block

Letter code to determine the function

GRID METHOD

We used the grid method to locate the position of the elements on the plan. On the y-axis, we divided the sheet into 6 spaces delimited by the letters A, B, C, D, E, F, G, placed from top to bottom and on the left margin of the paper.

Each sheet has been divided into 8 spaces on the abscissa, delimited by the numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, placed in consecutive order from left to right and on the upper margin of the paper.

The number of divisions that determines the number of grid squares is arbitrary and depends on the needs of the diagram. It is recommended to clearly define the components in distinct zones. The resulting grid squares are generally larger than those used in the example diagram.

Outline with more than one sheet:

As you can see in the bottom right margin, the sheets are numbered as follows: sheet 1/2, sheet 2/2, so you know the number of the sheet you're on and the total number of sheets. This numbering is usually done in the box of the plan used by the company, consultancy, etc.

Whether boxes are drawn on all sheets or only on the first one, the main schemes and the control schemes are always drawn separately; the main scheme in single-line or multi-line form, and the control scheme in developed form.

There are 3 possible scenarios:

a. That each main and control diagram occupies a single sheet. This is the case shown in the diagram in this example.

b. Both diagrams should be placed on the same sheet of paper. The main circuit diagram should be on the left, and the control circuit diagram on the right.

c. First, draw the complete diagram of the main circuit, using all the necessary consecutive sheets, and then draw the entire control circuit, also using the required consecutive sheets. Number the sheets by marking the sequential number and the total number used, starting with the first sheet of the main circuit, and then continuing with those of the control circuit. This creates a continuous and uninterrupted numbering system.

Identification and location of the components in the diagram

Attached auxiliary circuit:

In the developed control circuit, sheet 2/2 on reference column 4 (control circuit l) the attached auxiliary circuit formed by the coil and all its contacts is placed, providing us with the following information:

Identification block (-) that tells us the class (K), number 1 and function (M) of the control element.

For example, the identification symbol for the class, number and function of contactor number 1 that drives the main motor is: -K1M.

Marking of coil terminals A1 – A2.

Marking of terminals of the main and auxiliary contacts.

Sheet number and reference column on which the contacts are located in the plan.

This information is provided by the mark located to the left of each symbol.