Aesy's target characters are what shape



7. Documentation
7.1 Company-specific circuit diagrams
As in almost all technical professions, the electrician must work in drawings
represent. Unlike in the metalworking professions, where great emphasis is placed on accuracy
and surface treatment, a lot is used in the electrical professions with symbols and
Symbols worked. Magenau are actually just the assembly drawings. For each main division
In the broad field of electrical engineering, the circuit symbols were combined in DIN regulations.
collected. There are countless regulations on circuit symbols. Only a few are listed here.

DIN 40 712 General symbols

DIN 40 713 switching devices
DIN 40 703 additional circuit symbols
DIN 40 713 switches in energy systems
DIN 40 714 reactors and transformers
DIN 40 711 lines and line connections
DIN 40 717 circuit symbols for installation plans

You have to be careful with older plans, these DIN standards are also sometimes
changed or adapted to international regulations within the framework of the EU.

In the past, the drawings were made by hand in various formats, requiring a great deal of personnel
drawn. Today the drawings are created with a PC, the software for this is provided by the
offered by a wide variety of companies. The format is mainly A3 or A4. Self-
Understandably, you can also get the drawings on a data carrier. For various modern
ne switching devices (converters, soft starters, PLC systems) there are no standardized symbols because
these devices can be connected differently depending on the make. For these devices the
Draftsmen develop a device symbol themselves on the PC.

The following drawings are required for today's larger construction projects:

Circuit diagrams
Terminal plans
Cable lists
Construction plan
Function plans

The circuit diagram and the terminal diagram are the most important drawings for the operator

State Environment Agency North Rhine-Westphalia
- 169 -
7. Documentation

7.2 Circuit symbols according to DIN 40 713, 40 703, 40 717, 40 719

State Environment Agency North Rhine-Westphalia
- 170 -
7. Documentation

Circuit symbols for installation plans (extract from DIN 40 717)

State Environment Agency North Rhine-Westphalia
- 171 -
7. Documentation

State Environment Agency North Rhine-Westphalia
- 172 -
7. Documentation

Fig.7.1: Circuit symbols

State Environment Agency North Rhine-Westphalia
- 173 -
7. Documentation

Code letters of the device types according to DIN 40719 (old standard)

Code letter Type of equipment Examples

a Switch disconnector, load switch, motor switch
Command switch, control switch,
b auxiliary switch
Pushbutton switches, selector switches, etc.
c Treasures of achievement
Auxiliary guards, auxiliary and timing relays
d auxiliary treasures
Auxiliary remote switch
Fuses, measuring triggers,
e protective devices
Protection relay etc.
Instrument transformers, shunt resistors.
f transducer
And other donors
Voltage and ammeter
g measuring devices
Power and power factor measurement
Indicator and pointer indicator
h Visual and hearing alarms
Counters, alarm clocks, horns, etc.
k Capacitors All types of capacitors, inductors
Machines and generators, motors, converters,
Transformers transformers
Rectifier and rectifier and inverter
Batteries, accumulators and galvanic elements
p tubes and amplifiers tube amplifiers etc.
Resistors and pre-resistors, protective resistors
Rapid regulator braking resistors
Other mechan. Whip operated magnetically or by motor
with elect. Drive valves
u combinations of whips
Fig. 7.2: Code letters according to the old standard

State Environment Agency North Rhine-Westphalia
- 174 -
7. Documentation

Labeling according to DIN 40719

The equipment is labeled in accordance with DIN 40719 with capital letters:
Code letter Type of equipment Examples
Assemblies amplifier with transistors
Sub-assemblies magnetic amplifier
thermoelectric sensors
Converter of non-electrical
B dynamometer
Size to electrical size
Rotary field encoder
C capacitors
Binary elements bistable elements
Delay devices monostable elements
Lighting equipment
E miscellaneous
Heating devices
F protective devices
surge arrester
rotating generators
G frequency converter
Power supplies
H Signaling devices Optical and acoustic signaling devices
Performance assets
Relay auxiliary treasures
Protect time relays
Flasher relay
L inductors choke coils
M motors
Amplifier facilities of control and
Controller control technology
Measuring devices indicating, writing and counting
Test equipment measuring equipment
Circuit breaker
Q Power switchgear
adjustable resistors
R resistances
Control switch, button
S limit switch
Coupling stage
Voltage converter
T transformer
Power converter
Converter of electrical size frequency converters
in other sizes inverter
V semiconductor transistors
W transmission routes
Terminals, plugs, isolating plugs
Socket strips
electrically operated brakes, clutches,
mechanical equipment compressed air valves
Cable replicas
Z closings, filters
Crystal filter
Fig.7.3: Code letters according to DIN 40719

Older drawings are still labeled according to the old standard, which can be sent to the
recognize small letters.

State Environment Agency North Rhine-Westphalia
- 175 -
7. Documentation

7.3 Order on a drawing

Circuit diagram in protection technology

The sheet is practically divided into quadrants. There are numbers at the top. These begin
left of 0 and go into double-digit areas on older drawings, into
DIN A4 from 0 to 9. The height of the sheet is marked from A to F when viewed from above.
If the main circuit is shown in the drawing, it is always started on the left.
At the beginning, the conductors, which are always on top for the main circuits, are the
Tension and the origin noted.

The procedure for the control circuits is somewhat different. This is always at the top of the drawing
higher potential is shown, with direct current the plus and with alternating current the phase. Opposite
the counter potential is then drawn. On the far left in front of or on the conductor
The future is noted and on the far right where the line will be continued. Usually it is the leaf
The streamlines for the counter potential should not be drawn so deep. Under the lines ms-
The contacts of the archer must still be drawn. These ladder plans from the individual
There are contactors and relays on adhesive film. You now make the contacts that are occupied
a short line and write behind it where you can find this contact again. On the same
Sheet is enough, the top number in which the current path is located is enough if it is on another sheet
the new sheet number must also be noted. The designation from A to F is rarely used.
On the far right, of course, there is always the legend. The sheet number is important.

Fig.7.4: Quadrant division

State Environment Agency North Rhine-Westphalia
- 176 -
7. Documentation

7.4 Circuit diagrams in electrical engineering

The circuit diagram is an important document for all electrical specialists when assembling
Devices, the construction of electrical systems and troubleshooting. The circuit diagrams show
all the details of a circuit. However, no technical or spatial access
shown together, as this impairs the clarity of the presentation.
The equipment of a circuit diagram is represented with the help of standardized circuit symbols.
ben. As a rule, additional notes are added to explain the circuit with important information
Complete information.
The following additional information can be found in detail:
- reference designations of destinations,
- coordination field numbers,
- Voltage, current, resistance and setting values ​​as well as information on tripping
- type designations of equipment and lines,
- Representation of connection points, terminals, connections and measuring points.

The equipment of an electrical system and their interaction are shown in the electricity
The route plan is presented in such a way that its mode of operation is as simple as possible during assembly
ge, inspection and repair can be recognized.

Circuit diagrams are drawn in different types of representation.

A distinction is made between the single-pole representation, preferably for the representation of simple circuit losses.
fe. (in Fig.7.5 left)
The multi-pole, with extensive current curves (in Fig. 7.5 in the middle).
The coherent representation in which the operating resources are visible next to each other
can be made (in Fig. 7.5 right).

Mechanical connections are drawn as a dashed line, suitable only for simple circuits
because the clarity is easily lost. This method of representation was earlier than
Circuit diagram and was also common for complex systems.
The dissolved representation is often used today. The individual resources are
identified by the corresponding identification letters on the circuit diagram. Therefore, the rumli-
the same way of representation. The following features characterize the graphic representation
Position of the circuit diagrams most commonly used today in an exploded view:

Main circuits and auxiliary circuits are always shown separately. Circuit diagrams

are always drawn in the de-energized and mechanically unbound state. Deviations
this requires a corresponding note in the drawing.

The current paths run as straight as possible from the grid pole (e.g. L1) to the grid pole (e.g. N)
Current paths within the circuit diagram should as far as possible without branches, free of intersections and without
Changes of direction take place.
The circuit symbols are preferably arranged vertically.
The components and equipment are labeled in accordance with DIN 40900.
Device names are usually attached to the left of the circuit symbol. Terminal
drawings are to the right of the terminals.
Individual parts of equipment or an electrical component, e.g. B. coils, openers or
he. Are identified by the same device designation.

State Environment Agency North Rhine-Westphalia
- 177 -
7. Documentation

The complete circuit symbol, the so-called contact mirror, is displayed under each protection coil.
brings. From this you can see with which switching elements the contactor is equipped and in which
switch the switching elements on the current path.

The functional description of the circuit diagram for the auxiliary circuit shown in Figure 7.5

looks like this:
The auxiliary circuit is connected to the 220 volt alternating current network via the control fuse at F2. The A-
Switching takes place via button S1 current path 5, switching off via button S2 current path 5.
The contactors K1 and K2 lying in parallel have a latch K1-13 / 14 via current path 6.
The signal light H1 is switched by the NO contact K2 13/14 in the current path 7. The signal
light H2 is switched by the NO contact K2 23/24 in current path 7.

Fig.7.5: Circuit diagram (single and multi-pole, current paths)

State Environment Agency North Rhine-Westphalia
- 178 -
7. Documentation

Contactor circuits according to the old standard

Circuit diagram of the overall circuit

The parts of every device are

drawn together.

Circuit diagram

left: of the circuit

Representation of the circuit without auxiliary
cables. Just the essentials
are drawn.

right: the control circuit

The circuit is shown in current paths
represents. The current paths are as straight as possible
to be shown in lines and without intersections.

overview plan

Overview plans are usually single-pole


Fig.7.6: Contactor circuits according to the old standard

State Environment Agency North Rhine-Westphalia
- 179 -
7. Documentation

Sample project

Fig. 7.7: Example of a reversing contactor circuit

7.5 The terminal plan

The terminal plan forms the interface to the periphery in every control cabinet. All equipment,
that are arranged outside the control cabinet must be connected via the terminal strip
become. If several control cabinets are screwed together in a row, the
they are electrically connected via terminal strips. Cross cabling within the cabinets is in the
Rule forbidden. (Transport problems)
The most important thing on the terminal diagram is the actual terminal strip, which is usually from the left
to the right across the sheet and of course numbered consecutively. Right next to it is
a small field for the tab connections, useful to indicate where bridges are placed.
At the top are the lines that go into the cabinet with the destination sign and
the pin assignment. The target sign is usually a contactor or relay in short
according to DIN 40719 and the connection assignment then has the number of the terminal on the device.
The destinations where the cables go are then entered downwards, either in the periphery
where the devices are entered with abbreviations according to DIN 19227, or to the other clamping
in the neighboring cabinets, which are always marked with X and then consecutively numbered
are designated merged.

The cable plan is usually included in the lower part of the terminal plan. This plan is
structured like a matrix. On the far left are the cable types with the number of wires and the cross
cut. The wire numbers that are attached to the terminal are then under the actual terminal strip.
me are connected and on the far right you can then enter how many wires are connected

State Environment Agency North Rhine-Westphalia
- 180 -
7. Documentation

are and how many are still free. Basically it is forbidden to connect two wires under one terminal.
to close, there are bridges or tab connections.
(Signs of bad planning)
At the very bottom of the sheet is the legend sheet number, etc.
The types of terminals used are often entered here as well.

Fig.7.8: Terminal plan

State Environment Agency North Rhine-Westphalia
- 181 -
7. Documentation

7.6 Block diagrams and their special features

When describing the function of complex circuits, the mode of operation is expressed in terms of form
represented by block diagrams. This has the advantage that cable runs and internal circuits
of system parts and equipment in favor of the clarity of the circuit through block
like symbols can be replaced. Of course, this must not make the
Circuit functions are lost.
Additional notes and symbols that serve to describe the function of the system are
usually included in the block diagram. In addition to circuit symbols of the
Electrical engineering, the block diagrams also contain symbols for process engineering, the
Semiconductor technology, as well as binary element technology. Block diagrams are available from the
stated reasons for function descriptions in catalogs and technical documents,
because the type of display means that the function can be quickly understood.

For an example of a block diagram, see Chapter 4.9, Figure 4.31.

State Environment Agency North Rhine-Westphalia
- 182 -
7. Documentation

Control cabinet 1

Fig.7.9: Control cabinet

State Environment Agency North Rhine-Westphalia
- 183 -
7. Documentation

Control cabinet 2

Fig.7.10: Control cabinet

State Environment Agency North Rhine-Westphalia
- 184 -
7. Documentation

7.7 Test questions
1. What is meant by a circuit diagram in coherent or broken down

2. What do installation plans provide information about?

3. How is the number of conductors marked in the installation plan?

4. Enter the circuit symbol and circuit symbol for on / off switch, series switch and

Toggle switch on?

5. In what state are switches and circuits in installation circuits


State Environment Agency North Rhine-Westphalia
- 185 -
7. Documentation

7.8 exercise
Reading and explaining drawings that are available on site.

Basic circuits of electrical controls

Schtz to switch from one place
Prevailing by command
One command prevailing
And behavior / or behavior
Locking button / contactor interlocking

Switchover via Off
Switching is possible directly

Switch-off delay
Switch-on delay

Follow-up circuits
About treasures
About timers

Starting circuits for engines
Reversing circuits for actuators with end positions and torque
Star-delta connections
Pole changeovers
Dahlander circuits

For starting circuits, only use drawings that are also available on the system.

Provide a functional description of the contactor circuits shown in this chapter

to let.

Renaming of the abbreviations used in the representation of protection circuits, Chapter 7.4

the old norm into the new norm.

State Environment Agency North Rhine-Westphalia
- 186 -