JPH04315298A - Automatic duplex sensor switching device - Google Patents

Abstract

PURPOSE:To present the automatic duplex sensor switching device which can automatically and instantaneously switch a sensor to a sub sensor when a main sensor side is abnormal at a duplex sensor system. CONSTITUTION:Switch relays 6 and 7 are provided, the switch relay 6 detects the intermission of an analog input signal transmitted from a main sensor 1 to an input device 10 and corresponding to this detection, (a) contacts 6a and 7a and (b) contacts 6b and 7b of the respective relays 6 and 7 so that a sub sensor 2 can be connected to the input device 10 by switching. Therefore, when abnormality is generated on the main sensor side, it can be speedily and automatically switched to the sub sensor side without interrupting the control of the system or recording, etc.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic duplex sensor switching device for switching to a sub-sensor when a main sensor is abnormal in an instrumentation control system or the like.

0002

2. Description of the Related Art FIG. 3 is a configuration diagram showing a conventional sensor duplication system. In the figure, 1 is a main sensor, 2 is a sub-sensor, 3 is an external line of the main sensor 1, 4 is an external line of the sub-sensor 2, and 10 is a main sensor. 10a is a main input device into which the signal of sensor 1 is input; 10a is a sub-input device into which the signal of sub-sensor 2 is input; 12 is a DC power supply. FIG. 4 is a configuration diagram showing another example of the same system, and 11 is an external line 3.
Alternatively, it is a terminal block to which the outside line 4 is connected. Other parts are the same as FIG. 3.

Next, the operation will be explained. In the conventional sensor duplication system shown in FIG. 3, if an abnormality occurs in the main sensor 1 or the external wire 3 of the main sensor 1 is disconnected, the main input device 10 is not used, and the sub-input device to which the sub-sensor 2 is connected is used. Apparatus 10a is used. In the system shown in FIG. 4, if an abnormality occurs in the main sensor 1 or a break in the external wire 3 of the main sensor 1 occurs, the external wire 3 is removed from the terminal block 11 and the external wire 4 of the sub-sensor 2 is connected to the terminal block 11. Achieve sensor duplication function.

0004

[Problems to be Solved by the Invention] Since the conventional sensor duplication system is configured as described above, the system shown in FIG. 3 requires two input devices 10 and 10a, and the system shown in FIG. , it is necessary to manually switch the external lines 3 and 4 to the terminal block 11, and there are problems in that control or recording must be interrupted when switching.

[0005] This invention was made to solve the above-mentioned problems, and it requires only one input device, and when a sensor abnormality occurs or an outside wire is disconnected, the sub-sensor can be instantly and automatically sent to the sub-sensor without interrupting control and recording. The object of the present invention is to obtain a sensor duplication automatic switching device that can switch the sensor automatically.

[0006]

[Means for Solving the Problems] A sensor duplex automatic switching device according to the present invention is provided with means for detecting the presence or absence of an input signal from a main sensor such as a switching relay, and operates a switch circuit in accordance with the detection. It is designed to switch to a sub-sensor.

[0007]

[Operation] The sensor duplication automatic switching device according to the present invention automatically switches to the sub-sensor by activating the switch circuit when the input signal from the main sensor is disconnected, thereby preventing interruption of control and recording due to sensor abnormality or disconnection of external wire. highly reliable control with one input device,
Records can be made.

[0008]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as those in FIGS. 3 and 4 are given the same reference numerals, and their explanation will be omitted. In FIG. 1, 5 is the outer box of this device, 6 is a switching relay as a detection means for the main sensor 1, 6a is an a contact of the switching relay 6, 6b is two b contacts of the switching relay 6, and 7 is a sub sensor 2 7a is the a contact of the switching relay 7, 7b is the two b contacts of the switching relay 7, 8 is the input signal bypass resistor of the main sensor 1, 9 is the input signal bypass resistor of the sub sensor 2,
10 is an input device that processes analog input signals from the main sensor 1 or the sub-sensor 2. Note that a switch circuit is constituted by the switching relay 7, the a contacts 6a, 7a, the b contacts 6b, 7b, etc.

Next, the operation will be explained. An external line 3 for the main sensor 1 and an external line 4 for the sub-sensor 2 are installed in separate paths as shown in FIG. Also, this device and the input device 10 are connected. When the main sensor 1 is normal, the switching relay 6 is energized, the a contact 6a of the switching relay 6 is closed, and the b contact 6b is open. Also, on the sub-sensor 2 side, b of the switching relay 6
Since the contact 6b is open, the switching relay 7 is not energized.
The a contact 7a of the switching relay 7 is open, and the b contact 7b is closed. Therefore, the analog input signal from the main sensor 1 is taken into the input device 10.

Next, if an abnormality occurs in the main sensor 1 or a break in the external wire 3 occurs, the analog input signal from the main sensor 1 is interrupted, and the magnetic field of the switching relay 6 is therefore removed, and the a contact 6a opens. B contact 6b closes and switching relay 7 is energized. As a result, the a contact 7 of the switching relay 7
A closes and b contact 7b opens. As a result, sub sensor 2
An analog input signal from is input to the input device 10. Note that the main sensor 1 and the sub-sensor 2 are current output type sensors.

Example 2. In the first embodiment, a relay is provided for switching, but a transistor circuit may be provided for switching. In addition, in the above Example 1, 2
Although two switching relays 6 and 7 are used, one switching relay may be used and its a contact, b contact, and c contact may be used.

Further, in the first embodiment, a current output type sensor was explained, but if the circuit configuration shown in FIG. 2 is used,
The main sensor 1 and the sub-sensor 2 may be voltage output type sensors, and the same effects as in the above embodiment can be achieved. Figure 2
Normally, the operation of a is performed by the switching relay 6 detecting an analog input signal based on the voltage from the main sensor 1.
Contact 6a is closed and b contact 6b is open. In addition, the switching relay 7 does not detect voltage, the a contact 7a opens, and the b contact 7
b is closed. Therefore, an analog input signal from the main sensor 1 is applied to the input device 10. If an abnormality occurs in the main sensor 1 or a break in the external wire 3 occurs, the switching relay 6 will no longer detect voltage, and therefore the a contact 6a will open and the b contact 6b will close. Therefore, the switching relay 7 detects the analog input signal from the sub-sensor 2, and the a contact 7
A closes and b contact 7b opens. As a result, sub sensor 2
An analog input signal from will be applied to the input device 10.

[0013]

As described above, according to the present invention, the switch circuit is switched in response to disconnection of the analog input signal from the main sensor to automatically switch to the sub-sensor. etc., has the effect of instantaneously switching to the sub-sensor without interrupting control, recording, etc., and obtaining highly reliable control and recording.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a sensor duplication automatic switching device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a sensor duplication automatic switching device according to another embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional sensor duplication system.

FIG. 4 is a configuration diagram of a conventional manual switching type sensor duplication system.

[Explanation of symbols]

1 Main sensor 2 Sub sensor 6,7 Switching relay 6a, 7a A contact 6b, 7b b contact 10 Input device

Claims (1)

[Claims] 1. A main sensor and a sub-sensor, a detection means for detecting the presence or absence of an analog input signal obtained from the main sensor, and when the detection means detects the analog input signal, the analog input signal is sent to an input device. and a switch circuit configured to send an analog input signal obtained from the sub-sensor to the input device when the analog input signal is not detected.