JPH0556550B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a status signal detection method for detecting a connection state between a control unit and one controlled unit among a plurality of controlled units in a control system. It is about the method.

[Conventional technology]

A conventional control system is shown in FIG. In FIG. 3, 1 is a control section, 2 is an address line, 3 is a control line, 4 is a response data line, A1, Ax, and An are controlled sections, and B1, Bx, and Bn are status lines.

Next, the connections, functions, operations, etc. of the system configured as described above will be explained. The control unit 1 is multi-connected to controlled units A1, ..., Ax, ..., An by address lines 2, control lines 3, and response data lines 4, and status signal lines B1,
..., Bx, ..., Bn are independently connected to the control section 1. The address line 2 is a signal line for selecting a controlled unit, the control line 3 is a signal line for transmitting control information for the controlled unit, and the response data line 4 is a signal line for transmitting control information from the controlled unit to the control unit. This is a signal line that transmits response data information.

The control unit 1 controls predetermined controlled units A1,...,
Send one of the n addresses of Ax, ..., An as address information via address line 2,
Select the controlled part Ax. The controlled unit Ax having the same predetermined address as the address information sent from the control unit 1 via the address line 2 returns a status signal to the control unit 1 indicating that the controlled unit Ax has been selected. do. On the other hand, the control unit 1 that sent the address information detects that the xth one of the n status signals has been selected based on this status signal, and after confirming that the controlled unit Ax is correctly connected, Control information is sent out via the control line 3, and response data information is received from the controlled unit Ax via the response data line 4.

[Problem that the invention seeks to solve]

According to the method described above, when n controlled units are connected, n status lines are required to detect that the controlled unit selected by the control unit 1 is correctly connected, and A problem has arisen in that it is often impossible to implement a control system in units with a limited number of terminals.

[Means for solving problems]

In order to solve these problems, the present invention
Generate a common square wave for the controlled section in the control section,
This common square wave is sent from the control section to the controlled section,
In synchronization with this common rectangular wave, a status signal obtained by dividing the frequency of the common rectangular wave with a frequency division ratio specific to the address number of the own station is generated from each controlled unit, and Sends a unique status signal to the control unit via multi-connection signal lines,
This status signal is detected in the control section.

[Effect]

In the present invention, each controlled unit generates a status signal obtained by dividing a common rectangular wave with a frequency division ratio specific to the address number of the own station, and this status signal unique to each controlled unit is transmitted to the control unit. By sending the signal to the control unit, the control unit can detect the status signal of any controlled unit by using two signal lines.

〔Example〕

FIG. 1 shows a control system to which an embodiment of the status signal detection method according to the present invention is applied.
In FIG. 1, 5 is a status line, and 6 is a rectangular wave output line. In FIG. 1, the same or equivalent parts as in FIG. 3 are given the same reference numerals. In FIG. 1, a control section 1 is multi-connected to a plurality of controlled sections A1, Ax, and An via address lines 2, control lines 3, and response data lines 4, as in FIG. The controlled section is multi-connected (wired OR) to the control section 1 via the status line 5.

The operation of the control system configured and connected in this way will be explained. First, the control section 1 sends address information and a rectangular wave signal of frequency f0 to each controlled section via the address line 2 and the rectangular wave output line 6. The controlled unit Ax, which has the same predetermined address as this address information, divides the frequency of the rectangular wave signal with the frequency division ratio corresponding to the address of its own station, and generates the divided rectangular wave signal (hereinafter referred to as “divided A rectangular wave signal) is sent to the control unit 1 via the status line 5. Further, each unselected controlled section does not divide the frequency of the rectangular wave signal and does not send out the divided rectangular wave signal. In this way, the status signal corresponding to each controlled section is transmitted to the control section 1.

2 shows status signal waveforms between the control section 1 and each wave control section in FIG. 2. The signal waveform in Figure 2 gives a frequency division ratio of 1/2 to the controlled part A1, 1/4 to the controlled part A2, 1/8 to the controlled part A3, and 1/16 to the controlled part A4. This is the signal waveform for the case. f0 in Figure 2 a
shows a square wave signal with a frequency of . The status signal from the controlled part A1 shown in FIG. 2b is a frequency-divided rectangular wave signal having a frequency of 1/2 of the frequency f0 of the rectangular wave signal, and the status signal from the controlled part A2 shown in FIG. The signal is 1/4 of that, the status signal from the controlled part A3 shown in FIG. 2d is 1/8 of that,
The status signal from the controlled unit A4 shown in FIG. 2e is a frequency-divided rectangular wave signal having a frequency of 1/16 of that signal.

〔Effect of the invention〕

As explained above, the present invention generates a common rectangular wave for the controlled unit in the control unit, sends this common rectangular wave from the control unit to the controlled unit, and generates its own address number in synchronization with the common rectangular wave. A status signal obtained by dividing the frequency of the common rectangular wave by a frequency division ratio specific to the control unit is generated from each controlled unit, and this status signal specific to each controlled unit is transmitted via a signal line by multi-connection. By sending the status signal to the control unit and detecting this status signal in the control unit, the status signal from any controlled unit can be detected using two status lines, without requiring a large number of status lines. Further, there is an effect that a control system can be realized even in a unit with a limited number of terminals.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a control system to which an embodiment of the status signal detection method according to the present invention is applied, and FIG. 2 is a waveform diagram for explaining its operation.
FIG. 3 is a system diagram showing a control system to which a conventional status signal detection method is applied. 1...Control unit, 2...Address line, 3...Control line, 4...Response data line, 5...Status line,
6... Rectangular wave output line, A1, Ax, An... Controlled section.

Claims (1)

[Claims] 1. In a status signal detection method in a control system configured of a plurality of controlled units having predetermined unique address numbers and a control unit that controls the controlled units, the control unit includes a common address for the controlled units. Generate a rectangular wave, send this common rectangular wave from the control unit to each of the controlled units, and generate the common rectangular wave at a frequency division ratio specific to the address number of the local station in synchronization with the common rectangular wave. By generating a frequency-divided status signal from the controlled unit for each controlled unit and sending the unique status signal for each controlled unit to the control unit via a signal line by multi-connection, A status signal detection method comprising detecting the status signal in this control section.