JPH0342559Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an analog repeater for a self-fire alarm system using multiplex transmission.

[Background Art] Fig. 3 shows an overall circuit configuration diagram that is the basis of this type of self-fire alarm system, and in this system, a plurality of lines _l1 ...
... are connected, and these lines l ₁ ... are two-wire type with a terminator 2 connected at the end, and an analog sensor 3 or a general sensor 4 is connected between the receiver 1 and the terminator 2. Multiple connections are made. Analog sensor 3 and line
l _{1 .} . . An analog repeater 5 is interposed between the receiver 1 and the receiver 1 for transmitting and receiving data by time division multiplex transmission. As shown in FIG. 5, this analog repeater 5 includes an A/D converter 6 that converts the analog signal an from the analog sensor 3 into a digital signal, and a data bus and a control bus for the A/D converter 6. A logic processing unit 8 is connected via a bus 7 to process data from the A/D converter 6 and process data transmitted from the receiver 1, and a logic processing unit 8 receives power from the voltage applied to the line l and performs logic processing. 8, a power supply means for supplying power to the A/D converter 6 and the analog sensor 3, a receiving means for receiving transmission data superimposed and transmitted on the line l, and sensing obtained by the analog sensor 3; The transmitting/receiving section 9 includes a transmitting means for transmitting data in a superimposed manner onto a line l.

Figures 4 a to c show the voltage waveforms on line l ₁ . . . Normally, line voltage V _H is applied from receiver ₁ to line l 1 . The monitoring band A of the sensor 4 is defined as a monitoring band A, and when it is detected that the line voltage has decreased below a predetermined level in the monitoring band A, the receiver 1 determines that the general sensor 3 has operated and issues an alarm. In addition, a voltage application band with the line voltage V _L is set at regular intervals, and this voltage application band is used as a scan band B in which the analog repeater 5 of the analog sensor 4 connected to the line is sequentially accessed. Band B is set sequentially on lines l ₁ . . . when access to all repeaters on one line is completed, scan band B is set on the next line. Here, the transmission signal transmitted in scan band B is formed as a set of start pulse ST, address data AD, control data CD, check sum SU, and return waiting period setting pulse RT of the return signal, as shown in Figure 4d. , are transmitted sequentially.

In scan band B, in each analog repeater 5, the logic processing unit 8 determines whether or not the address data AD of the transmission signal received via the transmitting/receiving unit 9 matches a preset address. Under the function of the logic processing unit 8, the control data CD is taken in and the control data CD is processed.
The sensing data from the A/D converter 6 is converted into a return signal based on They will send it back. The receiver 1 reads sensing data from the analog sensor 3 connected to the analog repeater 5 and determines whether or not a fire is detected. In this way, the status of the analog sensor 3 connected to each line _l1 ... is monitored by cyclic polling in the scan band B, and the general sensor 2 is monitored in the monitoring band A of the general sensor 2. This is possible.

However, such a self-fire alarm system has a problem in that it is weak against external noise and lacks reliability.

[Purpose of the invention] This invention was created in view of the above-mentioned problems, and its purpose is to create a highly reliable analog self-fire alarm system that is less susceptible to external noise and has a simple circuit configuration. To provide repeaters.

[Disclosure of the invention] The invention is based on a system in which power is supplied from a monitoring means such as a receiver or a trunk repeater via a line, and the line voltage is lowered to a certain level and a transmission signal is sent in a set scan band. When the address data of the received transmission signal matches the unique address set in advance, based on the control data of the transmission signal, the analog data of the connected analog sensor is taken in and sensed data is converted by the A/D converter. In an analog repeater of a self-fire alarm system that sends a return signal as a return signal to a monitoring means during a return waiting period of the transmission signal, means for detecting the reception timing of a start pulse of a transmission signal in a scan band, and a detection signal of the means The present invention is characterized in that it is provided with means for operating the A/D converters in synchronization and latching the output data of the A/D converters.

This will be explained below using examples.

Embodiment The present invention is basically used in a self-fire alarm system similar to the system shown in FIG. The figure shows a specific circuit of the embodiment. In this embodiment, the receiver 1 serving as the monitoring means sets the scan band B as shown in FIG. 8, and the detected start pulse ST is generated as a detection signal as shown in FIG. 2b.

However, the start pulse ST which is the detection signal of the lever
is inverted by the inverter 10 and becomes an analog write timing signal for the A/D converter 6. The A/D converter 6 operates upon input of this analog write timing signal, converts the analog signal an from the analog sensor 3 into a digital signal, and latches the data after the conversion period x has elapsed. This latch data is held until the next start pulse ST is received as shown in Figure 2c, and then
When ST is received, the analog signal an at that time is converted and latched in the same manner as described above. In this way, since the A/D converter 6 operates and latches data at the timing of receiving the start pulse ST, the sampling time data does not change, and the attached noise removal circuit etc. becomes sufficiently effective. Furthermore, if the latch data itself is determined to be undefined on the receiver 1 side, it can be confirmed by accessing the data multiple times using the transmission signal.

Incidentally, FIG. 2d shows the sampling timing of data input to the A/D converter 6.

[Effects of the invention] The present invention is configured as described above and includes a means for detecting the reception timing of the start pulse of the transmission signal of the scan band, and an A/D in synchronization with the detection signal of the means.
Since a means for operating the converter and latching the output data of the A/D converter is provided, even if disturbance noise occurs, the data is latched, so the data will not be corrupted and high reliability can be obtained. Timing of the latch is achieved by detecting the start pulse of the transmission signal, which has the effect of not complicating the circuit configuration, and by using the start pulse, A/D conversion processing can be easily performed with a single-chip microcomputer. Therefore, it is possible to configure the entire repeater circuit with a single-chip microcomputer.

[Brief explanation of the drawing]

Fig. 1 is a circuit configuration diagram of an embodiment of the present invention, Fig. 2 is a time chart for explaining the operation of the same, Fig. 3 is an overall circuit configuration diagram of the self-fire alarm system that is the basis of the invention, and Fig. 4 is a time chart for explaining the operation of the same as above, and FIG. 5 is a circuit configuration diagram of a conventional example, where l is a line, B is a scan band, AD is address data,
CD is control data, ST is a start pulse, RT is a return waiting period setting pulse, an is an analog signal, 1 is a receiver, 3 is an analog sensor, 5 is an analog repeater, 6 is an A/D converter, 8 9 is a logic processing section, 9 is a transmitter/receiver section, and 10 is an inverter.

Claims (1)

[Scope of utility model registration request] Power is supplied via the line from a monitoring means such as a receiver or trunk repeater, and the line voltage is lowered to a certain level and a transmission signal is sent in a set scan band, and the address data of the received transmission signal is When the address matches the unique address set in advance, the analog data from the connected analog sensor is taken in based on the control data of the transmission signal, and the sensed data converted by the A/D converter is used as a return signal to send the transmission signal back. In an analog repeater of a self-fire alarm system that sends the signal back to the monitoring means during a waiting period, there is provided means for detecting the reception timing of a start pulse of a scan band transmission signal, and an A/D converter in synchronization with the detection signal of the means. 1. An analog repeater for a self-fire alarm system, comprising means for operating the A/D converter and latching the output data of the A/D converter.