JPS5819181B2 - PCM telemeter device - Google Patents

Description

Detailed Description of the Invention The present invention detects the clock signal transmitted from the receiving section when the main transmission system etc. fails and switches to the backup transmission system (redundant system) to transmit pulse code modulated data (hereinafter referred to as PCM data). The present invention relates to a PCM telemeter device that transmits the following.

The parallel redundancy method, which switches to the backup transmission system and transmits PCM data when the main transmission system for transmitting and receiving PCM data in a PCM telemeter device fails, is a conventionally known technology as shown in Figure 1. .

In this telemeter device, a signal that is normally input is converted into PCM data by a transmitting main transmission system 11 of a transmitting section 10 and then transmitted to a receiving main transmission system 21 of a receiving section 20 via a data transmission line 1. are doing.

This receiving main transmission system 21 converts the received PCM data into a binary decimal code or an analog signal and outputs it for appropriate data processing.

In this case, even if a failure occurs in the semi-transmission system 11.21, it is essential to transmit the PCM data from the transmitter 10 to the receiver 20 in order to ensure the reliability of the telemeter device.

For this reason, generally, the main transmission system 11.21 is provided with a backup transmission system 12.22, respectively, and changeover switches 13a, 13'b are provided to selectively switch the input/output sections of the main transmission system 11 and the backup transmission system 12, respectively. In addition, changeover switches 23a and 23b' are provided at the input/output sections of the main reception transmission system 21 and the backup transmission system 22, and the main transmission system 21.
1 and the backup transmission system 12.22.

Therefore, generally from the main transmission system 11.21 to the backup transmission system 12
．． 22, the receiving section 20 detects that the PCM data is not being transmitted normally from the transmitting section 10, and based on this, the receiving section 20 sends a control signal for switching to the transmitting section 10, and the switch is activated. 13a', 13b,
23a and 23b are switched.

There are two methods for transmitting this control signal.

(1) As one of them, the telemeter device includes a clock generator in the transmitting main transmission system 11 of the transmitting section 10, and uses this clock signal to generate a synchronizing signal and transmits PCM to this signal.

Data is added and sent to the receiving section 20 side, and the receiving section 20 side extracts a synchronization signal and reads the PCM data as data reading timing.

In this case, the PCM data after the synchronization signal is, for example,
II, f+ 111... or tlQt+
, ? +09"...... is received in succession, the determination circuit or the like determines whether the transmission and reception main transmission system 11.
21, it is determined that there is a failure and an alarm signal etc. is generated.

Based on this, the receiving section 20 side artificially operates the receiving control section 24 shown in FIG. 1 to issue a switching command.

As a result, on the receiving section 20 side, the reception control section 24 controls switching of the changeover switches 23a and 23b, and the reception control section 24 outputs a control signal for switching. Under switching control, both the transmitter 10 and the receiver 20 are switched to the backup transmission system 12°22.

■ The other method is to set a transmission period and a reception period in advance as shown in Figure 2, and during the transmission period, PCM data is transmitted from the sender's main transmission system 11 to the receiver's main transmission system 21, and a failure is determined from this data. If so, in the next reception period, the receiving unit 20 side
Send M control signal.

It is sent to the main transmission system 11 of the communication section 10, and the changeover switch 13a
, 13b, 23a, and 23b are switched to the backup transmission system 12.22.

However, method (2) requires a dedicated control signal line 2 to transmit control signals to remote locations.

It is not suitable for data transmission.

Another disadvantage is that it is difficult to synchronize on the receiving section 20 side when transmitting data at high speed.

On the other hand, in the method (2), the PCM data is paused and the control signal is transmitted in the next reception period.

The data transmission speed is reduced by the amount of control signal transmission.

Furthermore, if the output section of the transmitting main transmission system 11 of the transmitting section 10 becomes short-circuited or continues to transmit data, even if a control signal is sent from the receiving section 20, the transmitting section 10 cannot receive it. Switching to transmission system 12 becomes impossible.

The present invention has been made in view of the above circumstances, and
It is possible to perform data transmission at high speed without providing a special dedicated control signal line, and in the event of a failure in the main transmission system, etc., the changeover switch can be controlled to switch to the backup transmission system. An object of the present invention is to provide a PCM telemeter device that eliminates inconveniences.

In explaining one embodiment of the present invention with reference to FIG. 3, a recently developed telemeter device will first be described.

As described in the conventional example, the method (2) has a problem in that it is difficult to synchronize on the receiver side when transmitting data at high speed.

Therefore, recently, instead of having a clock generator in the main transmission system of the transmitter side, a clock generator is installed in the main transmission system of the receiver side, and a separate lock signal line is used to transfer the clock signal to the main transmission system of the transmitter side. A telemeter device has been developed in which the transmitter and receiver transmit PCM data in synchronization with each other.

In this case, there is an advantage that synchronization is less likely to occur and data can be transmitted at high speed.

Therefore, the present invention eliminates the conventional inconveniences in the above telemeter device when the main transmission system fails, and makes it possible to switch to the backup transmission system and transmit PCM data,
A detailed explanation will be given below with reference to FIG.

In FIG. 3, the same parts as those in FIG. 1 will be described with the same reference numerals.

In the figure, reference numeral 11' denotes a transmission main transmission system on the side of the transmitter 10, which converts, for example, an electrical analog signal or digital signal into PCM data and transmits it together with a synchronizing signal.

Reference numeral 21' denotes a reception main transmission system on the receiving section 20 side, which reads PCM data based on a synchronizing signal, stores it in a temporary storage circuit, performs binary decimal evolution or D/A conversion, and outputs the data.

The transmitting main transmission system 11' and the receiving main transmission system 21' are connected by a data transmission line 1.

Although not shown, the receiving main transmission system 21 has a built-in clock generator, which sends a clock signal to the transmitting main transmission system 11' through the clock signal line 3 and generates a synchronization signal from this signal. There is o 13a, 1
3b, 23a.

23b is a changeover switch for selectively switching between the main transmission systems 11' and 21' for transmission and reception and the backup transmission systems 12' and 22' for transmission and reception.

Reference numeral 12' denotes a transmission preliminary transmission system on the transmitter 10 side, which has a built-in clock generator (not shown) as described in the conventional example, and uses this clock signal to generate a synchronization signal. PCM data is added to the data and transmitted.

Reference numeral 22' denotes a receiving preliminary transmission line on the side of the receiving section 20, which extracts a synchronizing signal, reads PCM data as the PCM data reading timing, and outputs it in the same manner as the receiving main transmission system 21'.

Reference numeral 25 denotes a switch that is manually operated or automatically opened in the event of a failure in the main transmission systems 11', 21', and the changeover switches 23a, 23b are also switched in conjunction with this.

Furthermore, the dotted line shown in the receiving section 20 indicates that when the clock generator is automatically stopped in the main transmission system 21', it is also possible to change over the changeover switches 23a and 23b using that signal.

Reference numeral 30 denotes a switching control section that detects when there is no clock signal from the main reception transmission system 21 and switches the switches 13a and 13b to the transmission backup transmission system 12.

An example of this switching control section 30 has a configuration as shown in FIG. 4.

In the figure, 31 is a resistor R1. A smoothing circuit 32 consisting of a capacitor C1 is a voltage comparator which compares the voltages at the positive and negative inputs and outputs an inverted output.The output voltage VI of the smoothing circuit 31 is supplied to the negative input and the reference voltage 'RgF is supplied to the positive input.

33 is a relay drive circuit, and 34 is a relay.

The operation of the PCM telemeter device configured as above will be explained.

When the main transmission systems 11' and 21' are normal, when the input signal passes through the changeover switch 13a and enters the transmitting main transmission system 11', if the input signal is an analog signal, it is converted to a digital signal and then coded to z. , or in the case of a digital signal, encode it immediately and send this PCM data to the receiving main transmission system 21'.
It is added to the synchronization signal generated from the clock signal sent from the data transmission line 1 and output to the data transmission line 1.

The reception J main transmission system 21' that receives this synchronization signal and PCM data is synchronized in advance with the clock signal of the receiver side tank generator, so it reads the PCM data from the synchronization signal and converts it into a predetermined signal. and output it.

On the other hand, under normal conditions, the clock signal from the clock generator of the main reception transmission system 21' enters the switching control section 30 via the clock signal line 3 (see FIG. 5a).

This switching control section 30 smoothes the clock signal using a smoothing circuit 31, converts it into a voltage VI that is usually half the level of the clock signal (see FIG. 5), and supplies it to the four negative input sections of the voltage comparator 32.

This voltage VI is the reference voltage VR applied to the positive input section.
Since it is higher than EF, the positive voltage is inverted and a negative voltage of -12V is output, and the subsequent relay drive circuit 33 is not operated.

Therefore, under normal conditions, the switches 13a and 13b are maintained connected to the main transmission system 11' as shown.

Next, a case will be described in which the main transmission systems 11', 21', etc. fail.

There are various causes of this failure. (2) The clock input terminal of the transmitter's main transmission system 11' is short-circuited, or (2) The transmitter's main transmission system 11' or the receiver's main transmission system 21' itself is out of order.

In all of the above cases, the mode is set to switch to the backup transmission system 12'.

That is, in the case of failures due to ■ and ■, all can be detected by reading the synchronization signal and PCM data by the receiving main transmission system 21. Based on this, the clock generator is automatically stopped or the switch 25 Manually open the clock signal to stop transmitting the clock signal.

As a result, the receiving section 20 side switches from the main transmission system 21' to the backup transmission system 22'.

On the other hand, since no clock signal is input to the switching control section 30 of the transmitting section 10, this indicates that there is a failure.

At this time, in the switching control section 30, the reference voltage vREF is input only to the positive input section of the voltage comparator 32, so a voltage of +12V appears at the output of the voltage comparator 32, which causes the relay drive circuit to 33 and relay 34
to drive.

Then, the signal input section is switched to the backup transmission system 12' by controlling the changeover switches 13a and 13b.

Here, the backup transmission system 12' encodes the input signal, adds a synchronization signal generated by the clock signal from the built-in clock generator to the PCM data, and outputs it to the data transmission line 1.

The reception preliminary transmission system 22' that has received the synchronization signal and PCM data extracts the synchronization signal, reads the PCM data as the PCM data read timing, converts it into a predetermined signal, and outputs it.

When the main transmission systems 11', 21', etc. recover from the failure, the receiving main transmission system 21' automatically sends out a clock signal, closes the switch 25, and switches in conjunction with closing the switch 25. Switches 23a, 23b
is switched to the receiving main transmission system 21'.

Clock signals from the main reception transmission system 21'75) are input to the switching control section 30 through the clock signal line.

This switching control section 30 controls the changeover switches 13a and 13b to switch the signal input section to the backup transmission system 12'.

Note that PCM data transmission in the backup transmission system has the same configuration as a conventional telemeter device, and when transmitting data at high speed, it is difficult to synchronize on the receiver 20 side. It will be used until it returns to normal, so it is unlikely to cause any problems.

In addition, if the backup transmission system needs to have the same configuration as the main transmission system, a clock generator is installed in the reception backup transmission system.
This can be achieved by providing a clock signal line independent of the clock signal line of the main transmission system between the reception protection transmission system and the transmission protection transmission system.

As detailed above, according to the present invention, the presence or absence of a failure is determined using the existing clock signal line, and the system is switched to a standby transmission system in the event of a failure, so there is no need to set up a special dedicated line for switching. , reducing costs and eliminating the complexity of overhead line equipment.

Furthermore, conventionally, when the control signal input section of the main transmission system of the sender is short-circuited, it becomes impossible to switch to the backup transmission system, but this device can solve such a problem.

In other words, since the switching operation is performed reliably in the event of any abnormality, the reliability of the device is improved.Also, since there is no need to set up a reception period as shown in Figure 2, it does not affect the transmission of PCM data. This enables high-speed data transmission.

A brief description of the drawing.

FIG. 1 is a block diagram of a conventional device, FIG. 2 is a diagram showing the same transmission state for explaining the conventional example, and FIG. 3 is a block diagram of a conventional device.
A block diagram showing an embodiment of a CM telemeter device,
FIG. 4 is a configuration diagram showing an example of the switching control section shown in FIG. 3;
FIG. 5 is an operational waveform diagram of the switching control section.

1...Data transmission line, 3...Clock signal line, 10...Transmission unit, 11'...
Sender main transmission system, 12/-... Sending backup transmission system, 1
3a, 13b...Choice switch, 20...
...Receiving section, 21'...Receiving main transmission system, 22'
...Reception backup transmission system, 23a, 23b...
...Selector switch, 25...Switch, 30.
...Switching control section, 31...Smoothing circuit, 3
2... Voltage comparator, 34... Relay.

Claims (1)

[Claims] 1. A clock signal from a clock generator provided in the reception main transmission system of the reception section is sent to the transmission main transmission system of the transmission section via a clock signal line, and a synchronization signal is generated using this clock signal. PCM data is added to this and transmitted to the main receiving transmission system via the data transmission line, and the main sending transmission system is also equipped with a □transmission backup transmission system with a built-in clock generator. The transmission system is also equipped with a reception backup transmission system, which can perform transmission and reception backup transmissions in the event of a failure in the transmission and reception main transmission systems, respectively. In the telemeter device, a switching control section connected to the clock signal line is provided on the transmitting section side, so that the main receiving transmission system automatically or The transmission of the clock signal to the clock signal line is manually stopped (1), and the transmitting section detects the absence of the clock signal by the switching control section and switches from the main transmitting transmission system to the preliminary transmitting transmission system, and the receiving section When the main receiving transmission system automatically or manually stops sending out clock signals, the main receiving transmission system switches to the receiving backup transmission system. A PCM telemeter device characterized in that