JP2614363B2 - Method for reducing current consumption of optical transmission system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reducing current consumption of an optical transmission system, such as an optical LAN (local area network) or an optical communication system, which can reduce current consumption.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing a conventional optical transmission system. In this figure, 1 is a master transmission device, 2
a, 2b, 2c,... 2n are slave transmission devices, respectively.

[0003] These transmission devices 1, 2a, 2b, 2c,
.. 2n are connected to each other by a loop-shaped transmission path 3 made of an optical fiber, and an optical signal sent from the transmitter T of the master transmission apparatus 1 to the transmission path 3 is transmitted by the slave transmission apparatus 2a and the slave transmission apparatus 2b. , Slave transmission device 2
c, the master transmission device 1 via the slave transmission device 2n
Return to the receiver R. Each slave transmission device 2a, 2b, 2
c,... 2n of transmitter T and receiver R are fused optical coupler 4
Are connected to the transmission line 3 so that data can be exchanged with the master transmission device 1. Each slave transmission device 2a, 2b, 2c,... 2n is supplied with digital or analog data from outside. It should be noted that similarities to the optical transmission system having such a configuration are described in the specifications already filed by the present applicant (Japanese Patent Application Nos. 63-238103 and 63-275722).

A master transmission device 1 and each slave transmission device 2
Data transfer between a, 2b, 2c,... 2n is generally performed by a polling method. Hereinafter, a procedure of a general polling method will be described. It is assumed that the system conditions are as follows.

(A) First, the master transmission device 1 determines the number (slave address) of the slave transmission device for collecting data, puts it in a frame, and sends it to the slave transmission device. Immediately after this, it waits for reception of a frame from the specified slave transmission device. (B) Each slave transmission device 2a, 2b, 2c,... 2n that has received the frame transmitted from the master transmission device 1.
Determines whether the slave address described in the frame matches its own address number. (C) The slave transmission device whose slave address matches enters the response mode. (D) Then, the slave transmission device that has entered the response mode collects data (digital or analog data) to be transmitted to the master transmission device 1. (E) As soon as data collection is completed, a frame to the master transmission device is formed and a reply is made. (F) The master transmission device 1 receives the frame from the slave transmission device and ends collecting data from one slave transmission device.

The above is the general polling method. By the way, if polling is performed according to the above-described procedure, each of the slave transmission devices 2a, 2b, 2c,... 2n collects data at the time of the process (d), and therefore cannot immediately respond to the master transmission device 1. Therefore, there is a disadvantage that the time required for polling one slave transmission device becomes long. Therefore, in the case of an optical transmission system in which the polling cycle (period for polling one slave) is relatively short, data collection is performed as soon as (e) is completed, and the frame of the master transmission apparatus is received. In such a case, a response is immediately made. In this method, the data collected by the master transmission device is the data at the time of the previous polling, but does not pose a problem because the polling cycle is short.

As described above, in the method of collecting data as soon as (e) is completed and responding immediately after receiving the frame of the master transmission device, more data is collected from the slave transmission device within a shorter time. can do.
Here, FIG. 6 shows a transmission sequence of the master transmission device and each slave transmission device in this system. Note that in this figure, the symbol “to” is the time required for transmission (timeout time).

In the above-described optical transmission system having a relatively short polling cycle, a circuit having components that consume a large amount of current, such as an A / D converter and a DC / DC converter, in order to further reduce current consumption. The part operates only when used. Here, the current consumption in the optical transmission system will be described.

The current consumption in this optical transmission system can be obtained by the following equation. FIG. 7 shows an example of the consumption current waveform. Average current consumption = (t / T) × (Ip−Io) + Io t: Transmission and data input operation time T: Polling cycle Ip: Transmission and data input operation current Io: Steady reception standby current Average consumption of slave transmission device Current = (0.44 / T) × 0.07 + 0.03...

[0010]

By the way, in the above-mentioned conventional optical transmission system, in order to reduce current consumption, an A / D converter, a DC / DC converter or the like which consumes a large amount of current is used only. The other circuits are always in a state of waiting for reception so that they can respond to polling from the master transmission device. The
It is necessary to further promote a reduction in current consumption and to improve its maintainability. One reason for this Oyo formula described above
As can be seen from the equation , when T = 60 seconds, the current consumption becomes 30.3 mA.
Assuming that it is driven by an i (lithium) battery, 30.3
mA x 24 Ah x 365 days x 5 years = 1327.14 Ah
In consideration of a safety factor of 60%, 132.714 /
0.6 = 2211.9 Ah. And 125Ah
If a Li battery (67 x 165 mm, 0.95 Kg) is used, the voltage of the Li battery is 3.6 V. Therefore, assuming that the Li battery is used in series, 18 x 2 = 36 batteries. To 43.2 Kg. Therefore, if the current consumption is not reduced, the weight increases when the battery is driven, and the space increases due to the increase in the weight.

In the case of an optical transmission system having a relatively short polling cycle, data is collected as soon as the above (e) is completed, and a response is immediately sent when a frame from the master transmission device is received. However, in systems where low current consumption is strongly required, the polling cycle is often relatively long. Therefore, if the above-described method is adopted in this system, old data will be referred to.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and it is possible to access a slave at an arbitrary timing and to reduce current consumption of an optical transmission system capable of reducing current consumption. The purpose is to provide a method.

[0013]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, data transmission and reception are performed through a master transmission device and the master transmission device via an optical fiber. A plurality of slave transmission devices ,
At a specific timing determined for each slave device,
The master transmission device sequentially transmits data to each slave transmission device.
In an optical transmission system that collects data of each slave transmission device by polling for transmission and reception, only a circuit that detects a wake-up frame output from the master transmission device is operated during standby with respect to each slave transmission device, sometimes it detects a wake-up frame
Is a predetermined time after the delay time corresponding to each slave number
By operating all the circuits only during this time, the timing at which each of the slave transmission devices changes from the standby state to the operation state is delayed in the order of the slave numbers in accordance with the polling timing for each of the slave transmission devices.

[0014]

According to the above method, only the circuit portion for detecting a wake-up frame is operated for each slave transmission device during standby, and when a wake-up frame is detected, a predetermined delay time corresponding to each slave number is set after detection.
Since all the circuits are brought into the operating state only during the period , the current consumption can be reduced. In addition, since the slave transmission device is started by the wake-up frame from the master transmission device, the master transmission device can access the slave transmission device at an arbitrary timing, and each slave transmission device can be operated from the standby state to the operation state. Is determined by the unique timing determined for each slave transmission device.
Since the delay is made in the order of the slave numbers in accordance with the polling timing, unnecessary reception waiting time is minimized.

[0015]

Embodiments of the present invention will be described below with reference to the drawings . Although this embodiment is called a sleep standby system, it is different from a sleep standby system which has been conventionally used. The sleep standby method makes it possible to minimize current consumption during steady operation. However, the timing of transition from the standby mode to the active mode in which transmission is possible becomes a problem. That is, unless the slave transmission device is in the active mode, the master transmission device cannot perform polling.

Therefore, in consideration of workability at the time of system startup, maintainability, and data synchronization, it is required that the mode can be changed at any timing from the master transmission apparatus. The present embodiment enables such a thing. FIG. 1 is a block diagram illustrating a schematic configuration of an n-th slave transmission device 5n for describing a sleep standby method according to the present embodiment. In this figure, 6 is a 1:10 optical coupler, and 7 is a 1: 1 optical coupler. These optical couplers 6 and 7 take in an optical signal from the outside and take out an internal signal.
As shown in this figure, one of the four terminals of each of the optical couplers 6 and 7 is open, and a terminal connector is attached to these terminals. 8 is O / E (light / electricity)
The converter converts an optical signal supplied from outside via the optical couplers 6 and 7 into an electric signal and outputs the electric signal. The electric signal output from the O / E converter 8 is supplied to the communication circuit 9. The communication circuit 9 decodes the supplied electric signal, and reads a signal output from the interface circuit 10 based on the result of the decoding. Then, the read signal is converted to E / O (electric /
After being supplied to the (optical) converter 11 and converted into an optical signal, it is output to the transmission line 3 via the optical couplers 6 and 7. 12 is a power supply control, O / E converter 8 described above, the communication circuit 9 performs power control of the supply to each of the interface circuits 10, E / O converter 11. The power supply control 12 starts operation when the wake-up frame detection circuit 13 detects a wake-up frame, and at the same time, the timer 14 starts operating.
Control the power supply to each circuit by timer
The power supply is stopped when 14 counts up . In this case, the detection of the wake-up frame by the wake-up frame detection circuit 13 is as follows.
This is performed by detecting an optical signal by a communication photodiode provided in the first-stage amplifier portion of the O / E converter 8. The wake-up frame is a CMI signal of "a11" 1 "" and has a length of about 10 times that of a normal frame. This wake-up frame is transmitted by the master transmission device 1 before the polling operation starts. Also,
Since the wake-up frame is longer than the normal frame as described above, the wake-up frame detection circuit 13
The response of the circuit 13 is not required, so that the current consumption of the circuit 13 can be sufficiently reduced. Further, by using a photodiode for communication, the circuit can be simplified.

As described above, the first-stage amplifier portion of the O / E converter 8 and the wake-up frame detecting circuit 1
3 operates from the sleep standby mode (normal operation) after the power is turned on, the other circuits do not operate in the sleep standby mode, and are activated immediately after the wake-up frame detection circuit 13 detects the wake-up frame. Only works in mode. The operation will be described below in order. (A) When the power is turned on, the slave transmission device 5n
Go to sleep standby mode. Thereby, O / E
The first-stage amplifier of the converter 8 and the wake-up frame detection circuit 13 start operating. (B) The master transmission device 1 sends out a wake-up frame before starting the polling operation. (C) Upon detecting the wake-up frame, the slave transmission device 5n wakes up at a predetermined timing, activates each circuit, and takes in various data. Also,
The timer 14 is operated. (D) The master transmission device 1 polls the slave transmission device 5n and collects data. (E) The slave transmission device 5n operates the timer 14
Immediately after counting up, the mode returns to the sleep standby mode. Thereafter, each time a wake-up frame is detected from the master transmission device 1, the operations (b) to (c) are performed. By adopting such a method, the steady reception standby current Io can be set to Io = 0.0003 (A) or less.

Next, the time lag starting method will be described.
In the sleep standby method described above , the wake-up frame is detected at a plurality of slave transmission devices almost simultaneously. However, since the master transmission device polls in the order of the slave numbers, the later the order, the longer the slave transmission device waits in the active mode from wake-up to polling. Therefore, during this time, current is wasted. Also, in view of maintainability, it is not desirable that the current consumption of each slave transmission device is different from each other (because the battery used differs depending on the slave transmission device).

For power control, the timer 14
Control power supply to each circuit
To control the operation of each circuit. That is, wake
After detecting the up frame, the timing of timer 14
Has reached the wake-up wait time tww shown in the following equation
Each circuit is operated from the time when the
The timing of the access is necessary for the required polling
Each circuit is stopped at the time of the addition. tww = ( n- 1) × to ... n: slave number (n = 1 to N) to: timeout time (time required for the master transmission device to poll one slave transmission device)

Next, FIG. 2 shows a transmission sequence based on the sleep standby method and the time difference activation method described above. As can be seen from this figure , each slave wakes
After detecting the up frame, the timer 14 starts and the slave
Elapsed wake-up wait time for expression corresponding to number
After the circuit is activated, the required
By terminating the operation after the elapse of the active time ,
The transmission and data input operation time (active mode time) of each slave transmission device can be made substantially equal to the time in the conventional slave transmission device. here
Is the wake-up frame itself is substantially simultaneously received among the slave, according to the timing of the timer 14
For power control to each circuit of power control 12
Start-up is delayed according to each slave number.
Operation ends after the same active time. Ma
If Io = 0.3 mA according to the equation , the average current consumption Ix is: Ix = (t / T) × (Ip−Io) + Io = (0.4 / T) × (0.1−0.0003) ) + 0.0003 = 0.03988 / T + 0.0003 (A) Since the input data is assumed to be the same as the conventional one,
Ip was the same as before. FIG. 3 shows the current waveform.

Here, the relationship between the scan cycle, the number of years of use, and the battery will be described. The required battery capacity Vah is
Assuming a safety factor of 60%, Vah = (0.03988 / T + 0.0003) × 24 hours × 365 days × Y years / 0.6 (Ah) ... T: scan cycle (sec) Y: years of use (Year) For example, if the scan cycle is 3 minutes and used for 5 years,
Vah = 38Ah, 52φ × 94mm Li battery
It is sufficient to connect two (45Ah) in series. FIG. 4 is a graph showing the relationship between the required battery capacity Vah and the number of years of use for a scan cycle of 30 seconds, 1 minute, 3 minutes, 10 minutes, and 30 minutes. The batteries used in this case are the following three types. Since these batteries have an output voltage of 3.6 V, two batteries were connected in series. Size Weight Capacity Li Battery A: 27φ × 54mm 60g 6Ah × 2 Li Battery B: 52φ × 94mm 370g 45Ah × 2 Li Battery C: 67φ × 165mm 950g 125Ah × 2

[0022]

As described above, according to the above-described method, only the circuit portion for detecting the wake-up frame is operated for each slave transmission device at the time of standby, and when the wake-up frame is detected, each slave transmission device is sequentially operated in the order of the slave number.
Since all the circuits are brought into the operating state only for a predetermined time after the delay time corresponding to the above , the current consumption can be reduced. In addition, since the slave transmission device is activated by the wake-up frame from the master transmission device, the master transmission device can access the slave transmission device at an arbitrary timing and each slave transmission device is in a standby state.
From the state of the slave transmission device
Since the delay is made in the order of the slave numbers in accordance with the specific polling timing determined in the above , unnecessary reception waiting time can be minimized. Therefore, unnecessary current consumption during unnecessary reception waiting time can be eliminated.

[0023]

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a slave transmission device to which a method of the present invention is applied.

FIG. 2 is a diagram showing a transmission sequence between a master transmission device and a slave transmission device according to the method of the present invention.

FIG. 3 is a diagram showing a consumed current waveform according to the method of the present invention.

FIG. 4 is a diagram for explaining a relationship between required battery capacity and years of use.

FIG. 5 is a block diagram illustrating a schematic configuration of a conventional optical transmission system.

FIG. 6 is a diagram showing a transmission sequence between a master transmission device and a slave transmission device in a polling method applied to a conventional optical transmission system.

FIG. 7 is a diagram showing a current consumption waveform in a polling method applied to a conventional optical transmission system.

[Explanation of symbols]

 3 Transmission line 8 O / E converter 12 Power supply control 13 Wake-up frame detection circuit 14 Timer

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Toshimitsu Asakura 1440, Mukurosaki, Sakura-shi, Chiba Fujikura Electric Cable Co., Ltd.Sakura Plant in the factory

Claims (1)

(57) [Claims] And 1. A master transmission device, and a plurality of slave transmission apparatus transmits and receives data through the master transmission device and an optical fiber, is determined for each of said slave device
The master transmission device sequentially sets each scan at a unique timing.
In an optical transmission system that collects data of each slave transmission device by polling for exchanging data with a slave transmission device, a circuit that detects a wake-up frame output from the master transmission device during standby with respect to each slave transmission device Only when the wake-up frame is detected ,
Operation of all circuits only for a predetermined time after the delay time.
A method of reducing the current consumption of the optical transmission system, wherein the timing at which each of the slave transmission devices changes from the standby state to the operation state is delayed in the order of the slave numbers in accordance with the polling timing for each of the slave transmission devices. .