2.5 Relay- and relay group systems
2.6.1 Signatures of relay diagrams
In a diagram one can encounter signatures of several kinds of components. These are connected by wires, drawn as black lines. With a few exceptions, all the signatures will be connected by at least two wires and can be associated with pin numbers.
The following sections will describe the most essential signatures of a diagram.
2.6 Diagrams 26
Figure 2.8: An example of a diagram
2.6 Diagrams 27
2.6.1.1 Power Supplies
The power supplies are the origin of the current. From a more electrical point of view, it can be seen as a positive pole. They are drawn in diagrams as in figure 2.9. Their voltage and the type of current (AC∼or DC6=) are indicated near them.
Figure 2.9: A power supply Figure 2.10: A negative pole
2.6.1.2 Negative pole
The negative pole is not a physical component, but is represented in diagrams by an arrow like in figure 2.10.
Figure 2.11: A button
2.6.1.3 Buttons
As described in sections 2.5.2 and 2.7, buttons are used for interacting with an interlocking system and are located on an operator’s panel. An example of the signature of a button is shown in diagrams as seen in figure 2.11. One can find a button on the operator’s panel thanks to the coordinates given by the diagram (here x=006, y=06).
The signature of a given button can only occur once in a diagram. As the buttons are released in the normal state, the signature in figure 2.11 indicates that current cannot propagate through the part of the circuit where the signature occurs.
2.6 Diagrams 28
2.6.1.4 Regular Relays
Figure 2.12 shows a the signature of a regular relay in a diagram. It contains the following information:
• Where the relay is physically located:
In figure 2.12, the id of the relay, 87, makes it possible to find it in a physical relay room. In some cases, another notation is used to indicate more directly the location of a relay in the relay room: (level number, field number). In that way, the locations of the relays can be seen as a coordinate system.
• The two pin numbers that are connected to the circuit:
This gives another indication about the physical location of the relay: at one address (level number, field number), there can be two relays, a left position and a right position. In this case, the pin numbers (here 01 and 02) indicate that the relay is at the left position. If the relay had been at the right position, the pin numbers would have been 03 and 04.
• The state of the relay in the normal state:
The arrow to the left of the relay shown in figure 2.12 shows the state of the relay in the normal state of the interlocking system. In this case, the relay is dropped in the normal state, because the arrow is pointing downwards. If the arrow pointed upwards, the relay would be drawn.
• The role of a relay can be indicated by its signature:
The relay in figure 2.12 is used in the unlocking process and the relay in figure 2.13 monitors a signal. One can find more about the meaning of the different relay signatures in [16].
Figure 2.12: A regular relay (helping the unlocking process)
Figure 2.13: A regular relay (monitoring a signal)
2.6 Diagrams 29
2.6.1.5 Steel Core Relays
The signature of a steel core relay is shown in figure 2.14. Steel core relays are the only components that have three pins. The id of the steel core relay in the figure is 15. The output is on pin 02. The input that will draw the relay is on pin 01 and the input that will drop the relay is on pin 11. Pin 12 is not accessible.
Like regular relays, the state of a steel core relay is indicated by the arrow on the left of the relay. The only difference is that the end of the arrow is a black dot. In figure 2.14, the steel core relay is drawn, because the arrow is pointing upwards.
Figure 2.14: A steel core relay
2.6.1.6 Contact
A contact is like a switch that is ruled by a relay. For the contact in figure 2.15, relay 47 must be dropped in order to have the contact closed. The contact is linked to pins 91 and 92 of relay 47. As the normal state of 47 is dropped, the normal state of this contact is closed and current can propagate through it. As soon as relay 47 will be drawn, the contact will be open and the current will not be able to propagate through it.
Figure 2.16 shows a contact that is open in the normal state. The associated relay must be drawn in order to have the contact closed.
2.6.1.7 Other signatures
In diagrams, one can find other signatures that are not relevant for this project.
These signatures are mainly used for security and physical reasons and they do
2.6 Diagrams 30
Figure 2.15: A closed contact Figure 2.16: An open contact
not have any direct influence on the normal behaviour of an interlocking system.
• Fuses
A fuse as seen in figure 2.17 can cut current in case of an emergency or over-current.
• Resistors
The value and the location of the resistor in figure 2.18 are indicated on the side of it.
• Lamps
Lamps are used in the physical signals at the stations. In diagrams, the lamps will look like the one shown in figure 2.19. The colour of the lamp is indicated by its signature (gr for green,rø for red, andgu for yellow). A regular relay is always linked to a lamp in order to monitor it and enable the operator to know whether the lamp is on or off.
Figure 2.17: A fuse
Figure 2.18: A resistor
Figure 2.19: A lamp
2.7 The Operator’s Panel 31