JPH04239295A - Multiplex transmitter - Google Patents

Abstract

PURPOSE:To improve the detecting accuracy of a returned signal. CONSTITUTION:The returned signal is returned form a terminal equipment in a fixed cycle or at a specific point of time. This returned signal is A/D converted by an A/D converter 14. A signal processing part 10 finds optimal detection level and detecting pulse width from the A/D converted output. These detection level and detection pulse width are stored by a storage part 16. The reference voltage of a comparator 13 is set to the detection level stored by the storage part 16 corresponding to the terminal equipment at the time of the access of the terminal equipment, by a D/A converter 15. The signal processing part 10 decides the bit data of the pulse width of the returned signal outputted from the comparator 13 according to the detection pulse width stored by the stored part 16 corresponding to the terminal equipment.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex transmission apparatus for mutually transmitting signals between a base unit and a plurality of terminal units via a signal transmission medium.

0002

[Prior Art] A multiplex transmission device that transmits signals between a base unit and multiple terminal units via a signal transmission medium is used in lighting control systems, security systems, etc. in the home automation and viewer automation fields. There is.

0003

[Problems to be Solved by the Invention] By the way, in this type of multiplex transmission device, signals are transmitted between the base unit and the terminal using pulse signals, and the detection of reply signals from the terminal is difficult. This was determined based on the signal level and pulse width. However, in this type of multiplex transmission device, the level and pulse width of the return signal vary depending on the distance of the terminal from the base unit, the connection state, etc., so the return signal may not be detected satisfactorily.

The present invention has been made in view of the above-mentioned points, and its object is to provide a multiplex transmission device that can improve the detection accuracy of reply signals.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides determining means for determining the optimal detection pulse width and optimal detection level for each terminal, and the pulse width and the optimal detection level determined by the determining means. and detection means for detecting the reply signal at the level. Furthermore, if the above-mentioned determining means determines the optimal detection pulse width and optimal detection level for each bit, and the detecting means detects the reply signal using the determined pulse width and level for each bit, an even more accurate reply can be obtained. Signal detection becomes possible.

[0006]

[Operation] By configuring the present invention as described above,
The detection status of the reply signal on the base unit side can be adjusted according to the level and pulse width of the reply signal, which differs depending on the distance from the base unit and the connection status, etc., so that good response signal detection can be performed. It is something.

[0007]

Embodiment FIGS. 1 to 7 show an embodiment of the invention. As shown in FIG. 2, the multiplex transmission device of this embodiment connects a base unit A and a plurality of terminals B via a transmission line L consisting of two signal lines. Each terminal B is assigned a unique address, and the base unit A uses the address data AD in the transmission signal Vs in the format shown in Figure 3. Each terminal B is individually identified and accessed to transmit the control data CD that controls the operation of the load individually provided in each terminal B, and to indicate the operating status of the load from each terminal B. Have monitoring data sent back.

As shown in FIG. 3, the transmission signal Vs includes a start pulse ST indicating the start of signal transmission, mode data MD indicating the data transmission mode, address data AD indicating the address of terminal B to be accessed, and load information. It consists of control data CD indicating control contents, error detection data CS such as checksum data, and a reply standby signal WT that sets a reply period for monitoring data from terminal B. For example, it is a pulse width modulated bipolar signal. Time division multiplexed transmission is performed. In addition, each terminal B operates by rectifying and smoothing the transmission signal Vs transmitted from the base unit A via the signal line L to create a power supply, and the address data AD transmitted by the transmission signal Vs. When the and own unique address data match, the control data CD of the transmission signal Vs is taken in, and the monitoring data is converted into a current mode signal in synchronization with the reply standby signal WT of the transmission signal Vs (the distance between the signal lines L is omitted). short-circuited)) Reply.

FIG. 4 is a block diagram showing a schematic circuit configuration of the base unit A, and includes a signal processing section 10 consisting of a microcomputer that performs signal processing such as transmitting the transmission signal Vs and receiving the reply signal VB, and a signal amplifying section 11 that amplifies the logic level signal to a transmission level and sends it to the signal line L, and a reply section that detects the current mode reply signal VB sent back from the terminal B via the signal line L. It is composed of a signal detection section 12. Reply signal detection unit 1
2, as shown in FIG. 1, a comparator 13 detects the reply signal VB by comparing it with a certain level, performs waveform shaping, and outputs the reply signal VB as a logic level signal to the signal processing unit 10; A/D signal VB
The A/D converter 14 converts the digital data determined to be at the optimum detection level by the signal processing unit 10 according to the signal level of the return signal VB detected by the A/D converter 14. and a D/A converter 15 which supplies a reference voltage to a comparator 13. In addition,
The signal processing unit 10 determines whether the bit data is "1" or "0" depending on whether the return signal VB detected by the comparator 13 and subjected to waveform shaping is equal to or larger than a certain pulse width. The master device A of this embodiment includes a storage section 16 that stores the optimal level and pulse width for detecting a reply signal determined by the signal processing section 10 for each terminal device B.

FIG. 5 is a block diagram showing a schematic circuit configuration of terminal B, in which reception of the transmission signal Vs and reply signal VB are performed.
a signal processing section 20 consisting of a microcomputer that performs signal processing such as transmission of a signal, an address setting section 21 that sets a unique address for each terminal B, and a transmission section that detects a transmission signal Vs transmitted via a signal line L. A signal detection section 22;
It is comprised of a reply signal sending section 23 that sends out a current mode reply signal VB.

[0011] Now, when a transmission signal Vs with mode data MD as the control mode is transmitted from base unit A to terminal unit B,
This transmission signal Vs is detected by the transmission signal detection section 22 and sent to the signal processing section 20, and the signal processing section 20 operates the load according to the control data CD when the address data AD matches its own unique address data. Take control. Also,
When the transmission signal Vs with the mode data MD in the monitoring mode is sent from the base device A to the terminal B, the address data AD
If it matches its own unique address data, the monitoring data corresponding to the operating state of the load is returned to the main unit A in the current mode during the transmission period of the reply standby signal WT.

By the way, in this type of multiplex transmission device, for example, when the load connected to terminal B is an operating switch, interrupt processing is performed to detect the operating state of the operating switch. There is. In other words, when detecting the operation state of the operation switch, the main unit A uses the mode data M.
A dummy transmission signal Vs' with D in dummy mode is always transmitted. Then, when an operation switch serving as a load of one of the terminals B is operated, the terminal B transmits an interrupt signal in synchronization with the start pulse ST of the transmission signal Vs. Base device A, which has received this interrupt signal, searches for and identifies interrupt request terminal B, accesses the identified interrupt request terminal 2 using transmission signal Vs in individual access mode, and transfers the monitoring data in current mode. A reply is made using the transmission signal Vs.

Next, the characteristic operation of this embodiment will be explained. In this embodiment, all terminals B are polled at regular intervals, and each terminal B returns a reply signal VB.
The reply signal VB sent back at this time is sent to the A/D converter 14.
According to the output converted into a digital signal, the signal processing unit 1
0 determines the optimal signal detection level and pulse width for detecting the reply signal VB, and stores them in the storage unit 16. Then, during signal transmission such as when returning normal monitoring data, data indicating the detection level for the reply signal VB according to each terminal B is given to the D/A converter 15, and the detection of the reply signal VB in the comparator 13 is performed. This is performed using a reference voltage (b in FIG. 7 (a in the figure indicates a reply signal)) corresponding to the optimum detection level. Then, in the signal processing unit 10, the return signal V detected by the comparator 13 and waveform-shaped
The bit data is determined by comparing the pulse width of the terminal B with the pulse width for detection of the reply signal VB of the terminal B stored in the storage unit 16. In this way, the reply signal VB from the base unit A can be adjusted according to the level and pulse width of the reply signal VB, which varies depending on the distance from the base unit A, the connection state, etc.
The detection state of the signal can be adjusted, and a good return signal can be detected. A flowchart summarizing the above operations is shown in FIG.

[0014] In the above case, the reply signal V is sent periodically.
B is detected and the optimal signal detection level and pulse width for each terminal B are determined, but there may be cases where it is acceptable to make the above determination at the time of initial setting. By the way, even if the reply signal VB is from the same terminal B, the signal level etc. may change for each bit. In other words, in this type of multiplex transmission device, this phenomenon occurs because the terminal B receives power from the signal line L. Therefore, the operation shown in FIG. 6 is continuously performed during the reply period of the reply signal VB, and the optimal detection signal level and pulse width are determined for each bit, and the operation shown in FIG. The detection level may also be adjusted.

In the above case, a multiplex transmission apparatus employing a polling method has been described, but the present invention can also be applied to a multiplex transmission apparatus employing an N-to-N contention method. By the way, a typical example of this type of multiplex transmission device is the home bus system shown in FIG. A plurality of interface units (IFU) D corresponding to the machine B are connected via bus-type signal lines to mutually transmit signals. Here, the home bus controller C is connected to public telephone lines, antennas, etc., and the interface unit D is connected to communication devices such as telephones and facsimiles, AV devices such as televisions and stereos, and electrical equipment such as fire detectors, security sensors, and lighting. Devices etc. are connected. The signal format of the transmission signal transmitted in this home bus system is
As shown in FIG. 10, a priority code PR indicating the priority of the packet is used to control the contention of simultaneous message transmissions.
, self-address code SA indicating the source address, destination address code DA indicating the destination address, control code CC indicating the number of retransmissions, etc., data DATA for controlling and monitoring equipment as a load, error detection. code F
CC, response code (ACK/NAK) in next response period RP
) from the receiving side, a response standby signal ACK/NAK for responding to the transmitted signal from the receiving side up to the error detection code FCC,
and a rest zone for transmitting data from the receiving side.

Also in such a multiplex transmission device, the home bus controller C and each interface unit D send back reply signals to each other during initial settings such as when starting up the system, and each reply signal is sent in the same manner as described above. The optimal detection signal level and pulse width for detection are determined and stored, and when transmitting signals to each other, the detection level and pulse width are set according to the corresponding partner and the signal is transmitted. Just do it like this.

[0017]

Effects of the Invention As described above, the present invention includes a determination means for determining the optimal detection pulse width and optimal detection level for each terminal, and a detection method for detecting a reply signal at the pulse width and level determined by the determination means. Since the detection state of the reply signal on the base unit side can be adjusted according to the level and pulse width of the reply signal, which differs depending on the distance from the base unit and the connection status, etc., it is possible to detect a good reply signal. It has the advantage of being able to do

Further, if the above-mentioned determining means determines the optimum detection pulse width and optimum detection level for each bit, and the detecting means detects the reply signal with the pulse width and level determined for each bit, the output signal can be further improved. Accurate detection of the return signal becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main part configuration of a base device according to an embodiment of the present invention.

FIG. 2 is a system configuration diagram similar to the above.

FIG. 3 is an explanatory diagram of a signal format of a transmission signal same as the above.

FIG. 4 is a block diagram showing the configuration of the base unit same as the above.

FIG. 5 is a block diagram showing the configuration of the terminal device same as the above.

FIG. 6 is a flowchart showing the operation of the base unit same as above.

FIG. 7 is an explanatory diagram of a method for detecting a reply signal by the reply signal detecting section same as above.

FIG. 8 is an explanatory diagram when the optimum detection level is adjusted for each bit.

FIG. 9 is a system configuration diagram of another multiplex transmission apparatus to which the present invention is applicable.

FIG. 10 is an explanatory diagram of a signal format of a transmission signal same as the above.

[Explanation of symbols]

A Base unit B Terminal L Signal line 10 Signal processing section 12 Reply signal detection section 13 Comparator 14 A/D converter 15 D/A converter 16 Memory section VB reply signal

Claims (2)

[Claims] Claim 1. In a multiplex transmission device that connects a base unit and a plurality of terminals via a signal transmission medium and performs mutual signal transmission between the base unit and the terminals using pulse signals, 1. A multiplex transmission device comprising: determining means for determining the optimum detection pulse width and optimum detection level for each case; and detecting means for detecting a reply signal at the pulse width and level determined by the determining means. 2. The method is characterized in that the determining means determines the optimum detection pulse width and optimum detection level for each bit, and the detecting means detects the reply signal at the pulse width and level determined for each bit. The multiplex transmission device according to claim 1.