JPH0444996B2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention is applicable to fire alarm devices, smoke prevention and exhaust control devices,
The present invention relates to a transmission device for disaster prevention equipment such as a fire extinguishing control device, and particularly to a time division multiplex transmission device using pulse signals.

"Conventional technology" Conventionally used in disaster prevention equipment consisting of a central processing unit and multiple repeaters or terminals, transmission that controls the repeaters or terminals or transmits information in synchronization with the clock pulse of the central processing unit. There is a device. (For example, Special Publication No. 53-42582, Special Publication No.
53-46543) "Problems to be Solved by the Invention" In such conventional transmission devices, pulse signals are affected by the distributed constant circuit of the transmission path, and especially when the transmission path becomes long, The pulse signal becomes dull,
The rise and fall times become longer. Therefore, the pulse signal received and waveform-shaped is delayed by a magnitude related to the distance and electrical characteristics of the transmission path. If this delay time is short compared to the period of the clock pulse, the signal can be received without any problem, but if it is longer than this, the signal corresponding to the position of the clock pulse cannot be received. Therefore, the transmission distance is limited by the electrical characteristics of the transmission path and the clock cycle (transmission speed). If it is desired to extend the distance of the transmission equipment using a transmission line of the same quality, the clock period must be lengthened. That is, it is necessary to reduce the transmission speed. in this case,
When the number of repeaters and terminals connected increases, it becomes a problem that it takes too much time to transmit and control information.

"Means for Solving the Problems" The transmission device of the present invention slows down the clock cycle when transmitting signals from repeaters or terminals compared to the clock cycle when transmitting signals from the central processing unit. The present invention is characterized in that it is provided with a clock pulse generating means that can generate clock pulses.

``Operation'' Transmission distance can be extended without significantly reducing transmission speed.

Embodiment An embodiment of the transmission device of the present invention will be described based on the block diagram shown in FIG. 1 and the timing chart shown in FIG. 2.

In Figure 2, the disaster prevention device is the central processing unit RC.
, transmission lines LC, LT, and LR, and multiple repeaters or terminals RS. The transmission section of the central processing unit RC includes an oscillator 1 that generates a reference clock pulse, a counter circuit 2 for frequency division by n, and a flip-flop circuit 3 for frequency division by 2.
2-input AND circuit 4 and 3-input AND circuit 5
, a clock pulse generation means consisting of a two-input OR circuit 6 and a NOT circuit 7, a shift register 8 for parallel-serial conversion, a shift register 9 for serial-parallel conversion, output circuits 10 and 11, and an input circuit. 1
It is composed of 2.

The operation will be explained based on the timing chart shown in FIG. 2. The oscillator 1 outputs a rectangular pulse A of a constant period and inputs it to an AND circuit 4, a flip-flop circuit 3, and a counter circuit 2, respectively. The output of the flip-flop circuit 3 becomes a rectangular pulse B obtained by dividing the reference pulse by two. The output of the counter circuit 2 becomes a rectangular pulse C whose frequency is divided by n. When the output of the counter circuit 2 is high, the central processing unit RC is in a transmitting state, and when it is low, it is in a receiving state. The AND circuit 4 generates the same pulse as the rectangular pulse A only during transmission, and outputs a transmission clock pulse D which becomes low during reception. This is also used as a clock pulse for the shift register 8. The output of the counter circuit 2 is inverted by the NOT circuit 7 and input to the AND circuit 5. When the AND circuit 5 receives a reception clock pulse E, the pulse interval is doubled. This is also used as a clock pulse for shift register 9.
The OR circuit 6 outputs a pulse F which is a combination of the pulse D and the pulse E. This pulse F is output via the output circuit 10 to the transmission line LC as a clock pulse of the repeater or terminal RS. A shift register 8 for parallel/serial conversion converts parallel signals of addresses and commands from a central processing section (not shown) into serial signals and outputs them in synchronization with a clock pulse D for transmission. This signal pulse G is sent to the transmission line LT via the output circuit 11. The repeater or terminal RS receives clock pulses F and signal pulses G sent from the central processing unit RC through a transmission section (not shown). If the address matches its own address, it analyzes the command, performs control corresponding to the command, and sends back the information it currently has. This return signal pulse H is delayed compared to the clock pulse F due to the dullness of the pulse in the transmission path. This signal pulse H becomes dull while passing through the transmission line LR, and becomes a dull signal pulse H' before the input circuit 12. Waveform shaping in the input circuit 12 results in a further delayed signal pulse H''. This signal pulse H'' is input to the shift register 9, synchronized with the received clock pulse E, and the serial signal is converted into a parallel signal. Data collection and analysis of the converted parallel signals is performed in the central processing unit. The signal pulse H'' is delayed compared to the clock pulse E, but if it is smaller than the clock period, it can be received without any problem.The clock period is longer at the time of reception, so the delay range of the signal pulse H'' is delayed compared to the clock pulse E. You can also get a large amount. In other words, the transmission distance can be extended. In this way, the central processing unit
From the RC's point of view, the transmission distance can be significantly extended just by reducing the transmission speed during reception.

Signal pulse G sent from central processing unit RC
The number of bits, the clock cycle at this time, and the signal pulse H sent from the repeater or terminal RS
The number of bits and the clock cycle at this time are not limited to those shown in this embodiment, but can be easily implemented in various cases by using software such as a microcomputer. Also,
Transmission lines LC, LT, and LR are provided for each signal, but we use the synthesis and combination of each signal, the difference in signal form between voltage signals and current signals, etc.
It is also possible to implement each signal on the same line.

Generally, in a transmission device for a disaster prevention device, the amount of information (number of bits) sent from the central processing unit RC is the same as or larger than the amount of information (number of bits) sent from the repeater or terminal RS. This invention is particularly effective when the number of bits sent from the repeater or terminal RS is small, since the transmission speed is not reduced and the transmission distance can be extended.

"Effects of the Invention" As explained above, the present invention can provide a transmission device suitable for a disaster prevention device that can maintain transmission quality and increase transmission distance without significantly reducing transmission speed. Therefore, it is extremely useful for disaster prevention.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a transmission device for a disaster prevention device according to the present invention, and FIG. 2 is a timing chart. RC... Central processing unit, RS... Repeater or terminal, LC, LT, LR... Transmission line, 1... Oscillator,
2... Counter circuit, 3... Flip-flop circuit, 4, 5... AND circuit, 6... OR circuit,
7...Negation circuit, 8,9...Shift register, 1
0, 11...output circuit, 12...input circuit.

Claims (1)

[Scope of Claims] 1. Used in fire alarm systems, smoke prevention control devices, fire extinguishing control devices, etc., which are composed of a central processing unit and a plurality of repeaters or terminals, and which are used in clock pulses from the central processing unit. In a transmission device of a disaster prevention device that controls the repeater or terminal device or transmits information based on the clock cycle when the signal is sent out from the central processing unit, the clock cycle when the signal is sent out from the repeater or terminal device is A transmission device for a disaster prevention device, characterized in that it is provided with clock pulse generation means having different cycles. 2. The disaster prevention device according to claim 1, wherein the clock pulse generating means has a longer clock cycle when transmitting a signal from the repeater or terminal device than a clock cycle when transmitting a signal from the central processing unit. transmission equipment.