JPH0828688B2 - TDMA monitoring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a TDMA communication system in which communication between a plurality of slave stations and a master station is carried out in a time-divisional manner by allocation bursts allocated to the respective slave stations. For monitoring the status of slave stations
The present invention relates to a TDMA monitoring device.

In the prior art TDMA communication method, one radio wave is shared by one master station and a plurality of slave stations in a time division manner, and the communication between each slave station and the master station is assigned to each slave station. By using the allocated burst, a plurality of digital transmission lines are provided between the master station and the slave stations. Therefore, in the TDMA communication method, it is necessary for the master station side to monitor the states of a plurality of slave stations. For example, it is possible to access a specific slave station from the master station and monitor the status of the slave station based on the response from the slave station. However, if no response is obtained from the slave station, it is unknown whether the wireless device on the slave station side has a fault or the commercial power supplied to the slave station is cut off. That is, the conventional TDMA monitoring method described above has a completely different meaning in terms of maintenance.
There is a drawback that it is not possible to separately monitor the three causes of failure.

OBJECT OF THE INVENTION The object of the present invention is to solve the above-mentioned drawbacks of the related art, and when the commercial power supply of the slave station is cut off, the power cutoff information is transmitted from the slave station to the TDMA line without waiting for access from the master station. By using and sending it to the master station, the master station side can distinguish between failure of the device on the slave station side and power off and monitor
To provide a monitoring device.

Configuration of the invention, the TDMA monitoring device of the present invention, in the TDMA communication system for performing communication between a plurality of slave stations and the master station by the allocation burst allocated to each slave station, each slave station device, each operation In order to operate the device for a predetermined time even after the commercial power supply for power supply is cut off, a temporary voltage holding means for holding the voltage supplied to each device for a time longer than the time when at least one TDMA burst can be sent out, and the detection of the commercial power supply cutoff A power cut detection signal is provided, and the detection signal output by the power cut detection means is sent to the master station by mounting it on a predetermined bit in the allocation burst of the slave station. Of the above-mentioned detection signal sent to the predetermined bit to monitor the power-off of each slave station.

Embodiments of the Invention Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. That is, each slave station inputs the AC power supply voltage from the commercial power supply terminal 1 to the power supply circuit 4 via the power switch 2, and the power supply circuit 4 rectifies the input AC voltage,
It is converted into a DC voltage necessary for the operation of the TDMA circuit 5 and supplied to the TDMA circuit 5. The rectifier circuit generally includes a smoothing circuit, but in this embodiment, the smoothing circuit built in the power supply path circuit 4 keeps the TDMA circuit 5 for a predetermined time even after the input power from the commercial power supply terminal 1 is cut off. Special care has been taken to make it operational. That is, the power supply circuit 4 has a built-in temporary voltage holding means for holding a required power supply voltage for a certain time or longer in order to operate the device for a predetermined time even after the commercial power supply is cut off.

The temporary voltage holding means can be realized, for example, by connecting a large-capacity capacitor in parallel with the output of the power supply circuit 4. In addition, in many ordinary power supply circuits, a large-capacity capacitor is equipped as a smoothing capacitor, and it is often unnecessary to connect it to the outside.

The TDMA circuit 5 receives the signal on the allocation burst allocated to itself based on the frame signal transmitted from the master station 6, and also transmits the transmission signal to the allocation burst. A response signal to the access from the master station is also transmitted by the above allocation burst.

The power-off detecting means 3 monitors the state of the input AC voltage and outputs information about the on / off state of the commercial power source to output the TD.
It is supplied to the MA circuit 5. The TDMA circuit 5 constantly sends the output of the power-off detecting means 3 to a predetermined bit position on the assigned burst assigned to itself, as shown in FIG.

On the side of the master station, it is possible to recognize that the power of each slave station is normally supplied by monitoring a predetermined bit on the assigned burst of each slave station. When the commercial power supply on the slave station side is cut off, the power supply cutoff detecting means 3 of the slave station detects the cutoff of the power supply, and the TDMA circuit 5 sets a predetermined bit on the allocation burst to a logic indicating the power cutoff. Therefore, on the side of the master station, it is possible to determine whether or not the commercial power supply is cut off, based on the information in the bit. The information is not transmitted when the TDMA circuit 5 of the slave station whose commercial power is cut off becomes inactive after a predetermined time has passed after the power is cut off. Therefore,
On the master station side, it is necessary to detect the disconnection information within a predetermined time, that is, within at least one TDMA frame time.

The power-off detecting means 3 can be configured, for example, as shown in FIGS. The power supply disconnection detecting means shown in FIG. 3 rectifies the output of the voltage transformer 7 by the rectifier 8 and inputs the voltage obtained by smoothing the pulsating current output from the rectifier 8 by the capacitor 9 to the comparator 10, Reference numeral 10 detects the disconnection of the power source by comparing the voltage with the reference voltage VR input from the reference voltage terminal 11. When the power supply voltage is cut off at time t ₀ as shown in FIG. 6 (A), the output current of the rectifier 8 becomes as shown in FIG. 6 (D), and the smoothed voltage of the capacitor 9 becomes It gradually decreases as shown in E). This voltage is the predetermined reference voltage VR at time t _1.
In the following cases, the output of the comparator 10 is inverted and the power supply disconnection signal b as shown in FIG. Since the TDMA circuit 5 is supplied with an operating voltage from the power supply circuit 4, the output voltage of the power supply circuit 4 decreases until a predetermined time elapses after the power is turned off, as shown in FIG. Normally operates, and during this period, the power-off signal b is sent to a predetermined bit of the allocation burst.

The power disconnection detecting means shown in FIG. 4 (A) rectifies the output of the resistance voltage dividing circuit 12 by the rectifier 8 and supplies it to the optical coupler 13.
The output of the optical coupler 13 triggers the mono-multivibrator 14. The mono multivibrator 14 is an optical coupler 13
Is a re-triggerable mono-multivibrator that outputs a pulse having a period slightly longer than the period of the pulsating flow signal by regarding the pulsating flow signal output by the device as a trigger pulse. Therefore, the output f of the mono-multivibrator 14 becomes a continuous high level while the power is input as shown in FIG. 6 (F), and becomes a low level after a predetermined time when the power is cut off. Become. In this case, the optical coupler 13 is used to
It is possible to achieve isolation with the circuit 5 side, and it is possible to shorten the time from when the input power is cut off until the output f of the mono multivibrator 14 is inverted to the low level. As shown in FIG. 4 (B), two optical couplers 13a and 13b having opposite polarities are connected in parallel and are driven by the output of the resistance voltage dividing circuit 12. Even if the mono-multi vibrator 14 is triggered by the output, the same effect can be obtained. In this case, the rectifier 8 is not necessary. Further, since the trigger cycle of the mono multivibrator 14 becomes 1/2, the pulse width of the mono multivibrator 14 can be narrow.

In FIG. 5 (A), the output of the resistance voltage dividing circuit 12 is supplied to the optical coupler 13 via the rectifier 8, and the output of the optical coupler 13 is converted into a digital signal by the analog / digital conversion circuit 15 to generate a micro signal. This is a circuit which is input to the computer 16 and detects the power supply cutoff by monitoring the input signal by the microcomputer 16. The micro-computer 16 stores the pulsating flow signal output from the optical coupler 13 as a digital signal, compares the input signals with the repetition period of the pulsating flow signal, and detects commercial power supply disconnection due to waveform disturbance or voltage drop. To do. As shown in FIG. 6 (H), the detection output h of the microcomputer 16 is at a high level while the commercial power supply is normally input, and immediately becomes a low level when the commercial power supply is cut off. That is, since there is no circuit element having a time constant, there is an advantage that commercial power supply disconnection can be detected quickly. However, it is unavoidable that the configuration becomes slightly complicated. As shown in FIG. 5 (B),
The two optical couplers 13a and 13b are connected in parallel with opposite polarities and connected to the resistance voltage dividing circuit 12, and the output is input in parallel to the analog digital conversion circuit 15, and the output is input to the microcomputer 16. Of course, the same effect can be obtained.

As described above, in the present invention, each slave station device is provided with commercial power supply disconnection detection means, and the output signal of the power supply disconnection detection means is transmitted to the master station using a predetermined bit of the TDMA line. With this configuration, it is possible for the master station to monitor the power-off of the slave station by monitoring the predetermined bit of the allocation burst allocated to each slave station. That is, there is an effect that it is possible to distinguish between the failure of the slave station device and the disconnection of the commercial power supply. Therefore, it is not necessary to provide another monitoring line to convey the cause of inaccessibility to the slave station.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a predetermined bit for transmitting an allocation burst and a power-off signal in the above embodiment, and FIGS. 3 to 5 are each the above embodiment. FIG. 6 is a circuit diagram including a partial block diagram showing an example of the configuration of the power-off detection means of FIG. 6, and FIG. 6 is a time chart showing the signals of the respective parts of the above-mentioned embodiment. In the figure, 1: commercial power supply terminal, 2: power supply switch, 3: power supply disconnection detection means, 4: power supply circuit, 5: TDMA circuit, 6: master station,
7: Voltage transformer, 8: Rectifier, 9: Capacitor, 10: Comparator, 1
1: Reference voltage terminal, 12: Resistor voltage divider circuit, 13: Optical coupler, 14:
Mono multivibrator, 15: analog digital conversion circuit, 16: micro computer.

Claims (3)

[Claims] 1. In a TDMA communication system in which communication between a plurality of slave stations and a master station is performed by an allocation burst allocated to each slave station, each slave station device has a commercial power source used as a power source for the slave station. A voltage holding means for operating the slave station device for a time long enough to transmit at least one TDMA burst even after being cut off, and a power supply disconnection detecting means for detecting the commercial power supply disconnection, The detection signal to be output is sent to the master station by mounting it on a predetermined bit in the allocation burst of the slave station within the voltage holding time, and on the master station side, it is transmitted to the predetermined bit of the allocation burst of each slave station. A TDMA monitoring device that monitors a detection signal to monitor commercial power supply disconnection of each slave station. 2. The TDMA monitoring device according to claim 1, wherein the power supply disconnection detecting means is connected to a rectifier connected to a commercial power supply line via a voltage transformer and an output of the rectifier. A TDMA monitoring device comprising a capacitor and a comparator for comparing the voltage of the capacitor with a predetermined reference voltage. 3. The TDMA monitoring device according to claim 1, wherein the power supply disconnection detecting means is triggered by an optical coupler connected to a commercial power supply line via a voltage dividing circuit and an output of the optical coupler. And a multi-vibrator that is used for the TDMA monitoring device.