JPS62204399A - Measuring apparatus with disconnection detecting function - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a measuring device with a disconnection detection function.

(Prior art) Conventionally, when the process state is detected, a direct current of 1 to 5
A detector that outputs a signal after converting it into a V or 4 to 20 mA signal, a receiver that has an indicator, etc. that gives instructions based on the signal output from this detector, and a signal cable that connects these detectors and receivers. It consists of

Abnormalities in the detector and receiver can be detected using a tester, signal generator, etc. at each output end or input end, but disconnection of the signal cable can be detected.

There are two options: short-circuit one end of the cable and perform a continuity test using a tester from the other end, or perform a continuity test using a tester at both ends of the cable. In either case, disconnect the signal cable from the detector and receiver. In addition, if the signal cable was long, continuity testing at both ends of the signal cable was impossible.

(Problems to be Solved by the Invention) As explained in the prior art, in order to detect a disconnection of a signal cable, it is necessary to disconnect the signal cable from the circuit and use another tester or signal generator. There are some hassles that have to be done.

Continuity testing at both ends of the signal cable was not possible.

The present invention detects a disconnection of a signal cable without disconnecting the signal cable from the circuit as described above, and without preparing a separate tester, signal generator, or other testing device. It's about doing.

[Structure of the invention]

(Means for solving problems) The present invention relates to a detector for detecting the state of a process.

In a measuring device that consists of a receiver that inputs the output signal output from the detector and displays it on an analog or digital indicator, a rectifier is installed between the positive and negative electrodes that are the output terminals of the detector, and the receiver A signal generation section that generates an output signal that is the same as the output signal of the detector, a signal switching section that switches between the output signal of the detector and the output signal of the signal generation section, and when switched to the signal generation section side by this signal switching section. A measuring device with a disconnection detection function is characterized in that it includes a disconnection detection section having a function of detecting the presence or absence of continuity.

(for production) The present invention relates to a detector for detecting the state of a process.

In a measuring device that consists of a receiver that inputs the output signal output from the detector and displays it on an analog or digital indicator, etc., a rectifier installed between the positive and negative electrodes of the output end of the detector, and a a signal generating section that generates the same output signal as the output signal of the provided detector; and a switching section that switches the signal input to the two display sections.

Since a disconnection detection section for detecting the presence or absence of conduction is provided for each loop configured in the switching section, it is possible to automatically detect a signal cable disconnection when the disconnection detection section operates.

(Embodiment) FIG. 1 shows an embodiment of the present invention, in which a detector 1 for detecting the process state, a rectifier 2 provided between the positive electrode P and the negative electrode N which are the output terminals of the detector 1, and a receiver a signal generator 4 for outputting the same signal as the output signal of the detector 1 to the detector 3; a signal switching unit 5 for switching between the output signal of the detector 1 and the output signal of the signal generator 4; output signal and the signal generator 4
a display unit 6 that displays a signal obtained by switching the output signal of the output signal by the signal switching unit 5; and one of the output signals from the detector 1.

A disconnection detection unit 7 inputs one of the output signals from the signal generation unit 4, and the disconnection detection unit 7 detects whether there is continuity between the output signal of the detector 1 and the output signal of the signal generation unit 4, and determines the state. A measuring device with a disconnection detection function is shown, which includes contacts 8a and 8b that output signals accordingly.

FIGS. 2 to 4 show the operation of the present invention. In FIG. 2, 9 is in normal use condition.

The output signal of the detector 1 that detects the process state is displayed on the flow display section 6 as shown in the loop 9, and the normal function is performed. Detects that conduction is established. At this time, the signal switching section 5 is on the detector 1 side.

However, due to an abnormality in the detector 1, the output signal of the detector 1 may not be output, or the signal cables 10a and 10b may not be output.
If the wire breaks, the loop 9 will not be configured and the process status will not be displayed on the display section 6.

Furthermore, although the disconnection detection section 7 detects conduction, it is now possible to detect a non-conduction state.

Therefore, by switching the signal switching section 5 to the signal generating section 4 side, the output signal of the signal generating section 4 flows like a loop 11 shown in FIG. At the same time, the disconnection detection section 7 detects that the output signal from the signal generation section is conductive. When detector 1 is abnormal.

The signal generator 4 passes through the rectifier 2 with low impedance.
An output signal flows through the signal cable 10a.

If there is a disconnection in 10b, the loop 11 will not be formed.

As shown in the flow chart of FIG. 4, the above operation is determined to be normal if the output signal of the detector 1 is conductive by the disconnection detector 7 when the signal switching unit 5 is on the side of the detector 1, and it is determined to be abnormal. If there is continuity, the disconnection detector 7 outputs a command to the signal switch 5 to switch to the signal generator 4 side, and if the output signal of the signal generator 4 is conductive, the disconnection detector 7 outputs a command to the output 1 contact 8a. If the contact 8b is non-conductive, the contact 8b of output 2 is output.

As described above, according to the present invention, not only can a disconnection of a signal cable be automatically detected, but also an abnormality in the detector body can be detected. Furthermore, the instrument dynamic strain and cable impedance of the display section 9 can be opened, which is useful for maintenance of the measuring device.

(2) In the embodiment, the output signal from the detector is a DC current signal, but the same detection can be performed for a DC voltage signal as well.

In the example, the signal cable disconnection contact was output from the receiver, but the LED attached to the receiver was output by the contact.
It is also possible to display the information using a lamp on a display or the like.

〔Effect of the invention〕

As described above, according to the present invention, when a signal cable is disconnected, the disconnection of the signal cable can be detected by the disconnection detecting section, the signal switching device, and the signal generating section.

It is possible to detect a break in the signal cable without having to disconnect the signal cable from the circuit, and without preparing a separate tester, signal generator, or other testing equipment.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a measuring device showing a first embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams of the operation, and FIG. 4 is a flowchart of the main parts. 1. Detector 2... Rectifier 3... Receiver 4... Signal generator 5... Signal switching section 6... Display section 7... Disconnection detection section 8a, 8b... Contact 10a, 10b... Signal cable agent Patent attorney Nori Chika Ken Yudo Hirofumi Mitsumata Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] In a measuring device consisting of a detector that detects the state of a process, and a receiver that inputs an output signal output from the detector and displays it on an analog or digital indicator, the positive electrode that is the output end of the detector a rectifier provided between the negative electrodes, a signal generation section that causes the receiver to generate an output signal identical to the output signal, a signal switching section that switches the output of the detector and the output of the signal generation section, and this signal switching. A measuring device with a disconnection detection function, comprising: a disconnection detector having a function of detecting the presence or absence of continuity when the signal generating section is switched to the signal generating section side.