Vehicle-mounted transponder antennas are installed under the cab at both ends of the subway train. When the front of the train runs above the ground transponder, the antenna of the vehicle-mounted transponder will send electromagnetic energy to the ground transponder, and the ground transponder will convert this energy into working power supply, so that the electronic unit inside the transponder will start working and send the information such as line and speed stored in it to the train.
The active transponder has a special transponder cable connected to the ground electronic unit, which is installed next to the signal. The other subway lines depend on the situation, because the active transponder has a cable connection.
Therefore, the information stored in it can be changed at any time as needed. In addition to fixed line information, it can also send out variable information such as temporary speed limit and vehicle signal on-off as needed.
Passive transponder is a kind of transponder equipment without cables and any connecting wires, and its internal information cannot be changed at any time, so the data it transmits are fixed data. Passive transponder is generally installed between the section and the platform, which mainly transmits the fixed parameters of the line, such as the specified running speed of the line.
Active transponder and passive transponder are very reliable, and their failure probability is very low. When the wireless next to the track fails, the role of the transponder is highlighted. When active and passive repeaters are used together, they can transmit fixed line information and variable other information.
Therefore, transponder is an indispensable safety protection equipment for subway safety.
Extended data
The transponder equipment sends the following information to the on-board equipment of the train control vehicle:
(1) Basic parameters of the line: such as line gradient, track section and other parameters;
(2) Line speed information: such as the maximum allowable speed of the line and the maximum allowable speed of the train;
(3) Temporary speed limit information: when the running speed of the train is limited due to construction and other reasons, temporary speed limit information is provided to the train;
(4) station route information: provide "line gradient" for the train according to the vehicle route received and sent by the station.
Parameters such as "line speed" and "track section";
(5) Switch information: give the lateral allowable train speed of the front switch;
(6) Special positioning information: such as bow lifting, entering and leaving the tunnel, whistling, train positioning, etc.
(7) Other information: fixed obstacle information, train operation target data, connection data, etc.