JPS6319860Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a refueling device used in a refueling station such as a gas station, and particularly relates to an improvement of a data transfer device that connects refueling device devices.

As is well known, the widespread use of electronic equipment in gas stations creates a need for data transfer between such equipment. For example, the refueling price is obtained by multiplying the amount of refueling measured by a weighing machine by the unit price of the oil, but the unit price is set by a digital switch etc. installed on the operation console in the office to prevent it from being touched by outsiders. On the other hand, the refueling price is often calculated by a weighing machine control device built into the weighing machine, and in this case, the unit price must be data-transferred to the weighing machine. There are various methods for such data transfer, among them UART (Universal
A typical example is an asynchronous serial data transfer method using LSI (Asynchronous Receiver Transmitter) LSI. However, the data transfer device using the above-mentioned LSI has the disadvantage that the circuit is complicated and expensive.

In view of the above circumstances, this invention provides an inexpensive and highly reliable serial data transfer device for refueling equipment, which includes an oscillator that outputs clock pulses, and a pulse signal with a constant period by dividing the frequency of the clock pulse. a frequency dividing circuit, a transmitting circuit that converts parallel data into serial data based on these two series of pulses and serially transmits the data, and a receiving circuit that converts the serial data into parallel data based on the two series of pulses. It is characterized by comprising:

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In this figure, reference numeral 1 is a transmitting circuit installed in a console in an office, 2 is a receiving circuit installed in a weighing machine, and 3 is a receiving circuit installed in a weighing machine. It is a transmission line that connects them.

First, transmitting circuit 1 converts parallel data Dp into serial data.
16-bit shift register 4 for converting to Ds,
A digital switch (for example, a digital Samir switch) 5 supplies parallel data Dp of 4 bits each, a total of 16 bits, to the parallel input terminal of the shift register 4.
a to 5d and the clock terminal of shift register 4
a receiver 6 that applies a clock signal φ to CK;
Pulse signal to load terminal LD of shift register 4
Receiver 7 that supplies Sp and shift register 4
The serial data Ds supplied from the series output terminal Sout of
and a driver 8 that amplifies and supplies the amplified signal to the transmission line 3. Here, the digital switches 5a to 5
d is for setting the unit price of oil, 5a is in the thousandth place,
5b is for manually setting the hundreds digit, 5c is for the tens digit, and 5d is for manually setting the ones digit. Each of the digital switches 5a to 5d outputs a BCD (binary coded decimal) code corresponding to the set value.

Next, the receiving circuit 2 includes a 16-bit shift register 10 that converts the serial data Ds into parallel data Dp.
and a receiver 11 that receives the serial data Ds and supplies it to the serial input terminal Sin of the shift register 10.
, a latch circuit 12 that latches the 16-bit parallel data Dp supplied from the parallel output terminal of the shift register 10, and a meter control device that calculates the refueling price based on the parallel data Dp supplied from the latch circuit 12. 13, and a clock pulse φ with a constant period T is applied to the clock terminal CK of the shift register 10.
an oscillator 14 that supplies the clock pulse φ
A frequency divider circuit 15 divides the clock pulse φ by 1/16 to form a pulse signal Sp, and supplies this to the clock terminal CK of the latch circuit 12, and transmits the clock pulse φ and the pulse signal Sp to the transmitting circuit 1 side, respectively. It is composed of drivers 16 and 17.

Furthermore, the transmission path 3 includes a driver 8 and a receiver 11.
a transmission line 3a that connects and transmits serial data Ds,
The transmission line 3b connects the driver 16 and the receiver 6 and transmits the clock pulse φ, and the transmission line 3c connects the driver 17 and the receiver 7 and transmits the pulse signal Sp.

In such a configuration, the digital switch 5
The operation of this embodiment will be explained by taking as an example the case where the unit price "1234" is set by a to 5d. In this case, the digital switch 5a is manually set to "1", the digital switch 5b to "2", the digital switch 5c to "3", and the digital switch 5d to "4". Further, the oscillator 14 provided on the side of the receiving circuit 2 constantly outputs a clock pulse φ, so that the clock pulse φ is sent to each clock terminal CK of the shift registers 4 and 10, and to the load terminal LD of the shift register 4. Latch circuit 12
A pulse signal Sp is constantly applied to the clock terminal CK of the circuit. Here, the period of the pulse signal Sp is 16 times the period T of the clock pulse φ.

In such a setting, the time t ₁ shown in FIG.
A pulse signal Sp is output from the frequency dividing circuit 15,
When this is supplied to the load terminal LD of the shift register 4, parallel data Dp is set in each bit of the shift register 4 at the rising edge. That is, the 0th to 3rd bits of the shift register 4 are "1", the 4th to 7th bits are "2", and the 8th bit is "1".
~ “3” is stored in the 11th bit and “4” is stored in the 12th to 15th bits using BCD codes, so that each of the 3rd, 6th, 10th, 11th, and 13th bits is The other bits are set to a "1" signal and each other bit is set to a "0" signal. The thus set contents X ₀ to X ₁₆ (X _i is the contents of the i-th bit) of the shift register 4 are shifted one bit at a time every time the clock pulse φ rises and are sequentially output as serial data Ds from the serial output terminal Sout. Ru. That is, as shown in FIG. 2C, the signal X ₀ is output between time t ₁ and _{t 1} +3T/2,
Thereafter, the signals are sequentially outputted every time T as follows: X ₀ →X ₁ →...X ₁₅ . Therefore, in this case, the serial data Ds is “0”→“0”→“0”→“1”→……→“1”
→ “0” → “0” (see Figure 2 C). In this way, the parallel data Dp is converted into serial data Ds by the shift register 4, and transmitted to the receiving circuit 2 via the driver 8 and the transmission line 3a.

The serial data Ds transmitted to the receiving circuit 2 is applied to the serial input terminal Sin of the shift register 10 via the receiver 11, and is sequentially read into the shift register 10 at the falling edge of the clock signal φ. In other words, after time T has passed since time t ₁ , signal X ₀ has passed, and after time 2T has passed since _time t ₁ , signal X ₁ has passed...
At time _t2 after 16T has elapsed, the signal _X15 is sequentially taken into the shift register 10, and
The signal _X0 is set to the bit, the signal _X1 is set to the first bit, and the signal _X15 is set to the 15th bit. Then, at time t ₃ after time T from time t ₂ , the pulse signal Sp
The parallel data Dp (in this case " ₁₂₃₄ ") consisting of the signals X ₀ to
is latched to. In this way, one cycle of transmission and reception is completed, and the same cycle is repeated thereafter. In addition, parallel data latched in the latch circuit 12
Dp is read into the weighing machine control device 13 as necessary, and the refueling price is calculated from this parallel data Dp (unit price) and the refueling amount.

Note that if a photocoupler is used in the receivers 6, 7, and 11 described above, the transmitting circuit 1 and the receiving circuit 2 can be electrically isolated, thereby improving the explosion-proofing effect of the weighing machine. becomes. Further, although the above embodiment has been described by taking as an example the serial transmission of unit price data, it is of course possible to transmit other data in a similar manner.

As explained above, this invention consists of an oscillator that outputs clock pulses, a frequency dividing circuit that divides the frequency of the clock pulse and outputs a pulse signal of a constant period, and converts parallel data into serial data based on these two series of pulses. Since the transmitting circuit includes a transmitting circuit that serially transmits data, and a receiving circuit that converts the serial data into parallel data based on the two series of pulses, data can be transferred using only three transmission lines. Furthermore, if an oscillator and a frequency dividing circuit are provided on the receiving side, the receiving side can control the transmitting side, thereby avoiding idle feeds and the like, thereby increasing the reliability of the device. Furthermore, since there is no need to use a special IC and the circuit configuration is simplified, the device has the advantage of being cheaper. Additionally, the receiving side has the effect of always being able to obtain the latest data.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of an embodiment of the present invention, and Fig. 2 shows the clock pulse φ and the pulse signal.
FIG. 3 is a waveform diagram showing waveforms of Sp and serial data Ds. 3... Transmission line, 4... Shift register (parallel/serial conversion circuit), 10... Shift register (serial/parallel conversion circuit), 12... Latch circuit, 14... Oscillator,
15... Frequency divider circuit, Dp... Parallel data, Ds...
Serial data, Sp...pulse signal (output signal of frequency divider circuit), φ...clock pulse.

Claims (1)

[Scope of utility model registration request] a parallel-serial conversion circuit that converts parallel data into serial data; a transmission path that serially transmits the serial data; and a serial-parallel conversion circuit that converts the serial data transmitted via the transmission path into parallel data;
a latch circuit that latches the parallel data obtained by the serial-parallel conversion; an oscillator that supplies clock pulses to the parallel-serial conversion circuit and the serial-parallel conversion circuit; and an oscillator that divides the frequency of the clock pulse and converts the output pulse to the 1. A serial data transfer device for a fuel supply system, comprising a frequency dividing circuit that supplies a load terminal of a serial conversion circuit and a clock terminal of the latch circuit.