JPS5913961A - Monitoring device of electromagnetic fluid state - Google Patents

Abstract

PURPOSE:To obtain a stable, reliable monitoring device for the state of electromagnetic fluid by detecting the breaking of wire of an electromagnetic detector securely even during the continuation of control over the electromagnetic fluid, and performing the control corresponding to the breaking of wire. CONSTITUTION:A reference voltage is applied from a reference voltage power source 10 to the electromagnetic detector 2 all the time and the detection signal of the electromagnetic detector 2 is inputted to an amplifier 11 through said reference voltage power source 10 and amplified by the amplifier 11, whose output signal is compared with a specific value by a voltage comparator 14 to decide on the breaking of wire on the basis of the comparison result. The signal from the voltage comparator 14 is inputted to a wire-breaking detection bit setter 16, which outputs a wire-breaking detection bit to a part of the output of an integral counter 13, and the amplified detection signal from the amplifier 11 is supplied to a voltage frequency converter 12 through a reference voltage subtracting circuit 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic fluid condition monitoring device, and in particular, to a device capable of detecting disconnection of an electromagnetic detector even during control of the electromagnetic fluid so as to continue controlling the electromagnetic fluid. The present invention relates to an electromagnetic fluid condition monitoring device.

Generally, the electromagnetic fluid condition monitoring device has the configuration shown in FIG. In FIG. 1, 1 is a magnetic fluid, 2 is an electromagnetic detector, 3 is a magnetic fluid control equipment, 4 is an electromagnetic detection signal processing device, 5 is a magnetic fluid control device, 6 is an electronic computer, 7
is a control cycle clock generator. Same, the monitoring control device 500, the electromagnetic fluid control equipment 3, the electromagnetic fluid control device 5,
It is configured to include an electronic computer 6 and a control cycle clock generator 7. That is, the electromagnetic fluid state monitoring device includes an electromagnetic detector 2 that detects the state such as the position of the electromagnetic fluid, and a detection signal from the electromagnetic detector 2, and integrates the detection signal to detect the state of the electromagnetic fluid 1. The electromagnetic detection signal processing device 4 detects all the amount of change in position, receives the position change amount signal from the electromagnetic detection signal processing device 4, and detects the target position at every fixed cycle clock from the control cycle clock generator 7. and an integrated input signal of the electromagnetic fluid 1, calculates a control amount according to the comparison position, and outputs a control signal. The electromagnetic fluid control device 5 is comprised of a magnetic fluid control device 5 that generates a control command signal, and a magnetic fluid control equipment 3 that corrects the position of the magnetic fluid 1 based on the command signal from the magnetic fluid control device 5.

The operation of the electromagnetic fluid condition monitoring device configured in this way will be explained below.

When the position of the electromagnetic fluid 1 moves by Δ, the number of magnetic flux linkages to the electromagnetic detector 2 changes, and thereby an electromotive force is generated in the electromagnetic detector 2.

This electromotive force is used as a detection signal, and the electromagnetic detection signal processing device 4 performs integration processing on this detection signal, thereby converting it into an amount of change in position of the electromagnetic fluid 1. This position signal is input to the electronic computer 6, and the target position is compared with the position change amount signal of the electromagnetic fluid 1 every fixed period clock from the control period clock generator 7, and the control amount is calculated according to the position change amount. do,
Output to the electromagnetic fluid control device 5. The electromagnetic fluid control device 5 controls the electromagnetic fluid 1 to a target position by sending a command signal to the electromagnetic fluid control equipment 3.

FIG. 2 shows a processing flowchart within the electronic if1' calculator 6 shown in FIG. In FIG. 2, when a control period clock is input from the control period clock generator 7 to the electronic computer 6, the flowchart process shown in FIG. 2 is started for each control period clock. When the startup is started every control cycle clock, the flowchart 1 shown in FIG. 2 starts at step 100.
First, a signal from the electromagnetic detector 2 is input. Next, the process moves to step 101, and the positional deviation of the electromagnetic fluid 1 is calculated. Once this deviation calculation is completed, step 1
Move to 02. In step 102, control tV is calculated and the process moves to step 103. In step 103, a control amount signal is output to the electromagnetic fluid control device 5. Then, the process of the process flowchart is ended.

FIG. 3 is a block diagram showing the configuration of a conventional electromagnetic detection signal processing device. In the figure, the electromagnetic detection signal processing device 4 inputs an electromotive force signal (detection signal) caused by a change in the position of the electromagnetic fluid of the electromagnetic detector 2 to an amplifier 11 to amplify the voltage, and performs an integration operation on the amplified signal. Therefore, the voltage is converted into a frequency by a voltage frequency converter 12, this frequency is counted by an integral counter 13, and the integrated counter value is detected and output as the amount of position change. By inputting the signal from this electromagnetic detection signal processing device to the electronic computer 6,
This realizes the control contents explained in the figure.

By the way, since the electromagnetic detector 2 is formed by winding a conducting wire into a coil, the conducting wire may be thermally and mechanically affected by the electromagnetic fluid and may break. Electromagnetic detector 2
When the wire is disconnected, the function of the electromagnetic detector stops, and therefore, control of the electromagnetic fluid 1 becomes impossible. Furthermore, the conductor wire of this electromagnetic detector 2 is generally wound with a thin conductor wire,
There is a high possibility of wire breakage due to distortion stress etc. under high temperature and high magnetic field.

For this reason, a Wr line detection function is essential.

Conventionally, as shown in FIG. 3, a reference voltage power supply 10 and a resistor 9 are arranged in parallel with the electromagnetic detector 2 in the electromagnetic signal processing device 4, and when checking for disconnection detection, the electronic computer 6 Outputs a disconnection detection command and switches switch 8.
By inputting , the value of the integration counter 13 is read and a disconnection check is detected. That is,
If the electromagnetic detector 2 is not disconnected, the voltage of the reference voltage 10 causes a voltage drop at the resistor 9, and the voltage input to the amplifier 11 becomes approximately 0; The voltage is output as is.

A method for detecting wire breakage using the electromagnetic detection signal processing device configured as described above will be explained with reference to the time chart shown in FIG. In FIG. 4, the horizontal axis represents time t, and the vertical axis represents changes in electromagnetic fluid position and control contents. In FIG. 4, a disconnection detection test is performed at time t1. This outputs a disconnection detection command from the computer 6 and switches 8
Close. At this time, if the electromagnetic detector 2 is not disconnected, the output from the amplifier 11 will be approximately 0, and control can be started. If it is OK to start the control, the control is started at time t2, a change in the position of the electromagnetic fluid 1 is detected every control cycle clock, and the control is ended at time t. However, when performing a disconnection detection test to check for disconnections before starting control, once control has started, the switch 8 that opens and closes according to the disconnection detection command in Fig. 3 needs to be open. . Therefore, conventionally,
Before starting control, disconnection was detected as described above, but
If a disconnection were to occur during control, it would be impossible to detect and there was a risk that the electromagnetic fluid control would go out of control. Particularly in the case of high-temperature, high-density electromagnetic fluid control, the influence of runaway on mechanical equipment is significant, and it is important to improve the reliability of control during control.

It is an object of the present invention to make it possible to reliably detect a disconnection of an electromagnetic detector even while the electromagnetic fluid is being controlled, and to perform control corresponding to the disconnection. To provide a stable, reliable electromagnetic fluid condition monitoring device.

In order to achieve the above object, the present invention constantly applies a reference voltage from a voltage reference power source to an electromagnetic detector, and detects a disconnection by comparing a detection signal received via the voltage reference power source with a predetermined value. In addition, when a wire breakage is detected, it is possible to immediately perform wire breakage handling processing. Furthermore, the present invention provides a plurality of electromagnetic detectors, and the electromagnetic detection signal processing device constantly applies a reference voltage to each of the electromagnetic detectors from a reference voltage power supply provided for each electromagnetic detector. Detection signals from each electromagnetic detector are captured through the reference voltage power supply, and when it is detected that the electromagnetic detector is disconnected based on the captured detection signal, the detection signal from other than the electromagnetic detector is detected. This signal is used as a signal to detect the amount of change in position of the electromagnetic fluid.

An embodiment of the present invention will be described in detail below based on the drawings.

FIG. 5 is a block diagram showing an electromagnetic detection signal processing device used in an embodiment of the electromagnetic fluid condition monitoring device according to the present invention. The embodiment of the electromagnetic detection signal processing device 40 shown in FIG. 5 differs from the configuration shown in FIG. 3 in that a reference voltage is constantly applied to the electromagnetic detector 2 from a reference voltage power source 10,
Further, the detection signal from the electromagnetic detector 2 is taken into the amplifier 11 via the reference voltage power supply 10, the taken-in detection signal is amplified by the amplifier 11, and the amplified detection signal from the amplifier 11 is subjected to voltage comparison. The signal from the voltage comparator 14 is input to the disconnection detection bit setter 16, and the disconnection detection bit setter 16 performs the integration. A part of the output of the counter 13 can be outputted as a disconnection detection bit, and the amplified detection signal from the amplifier 11 is supplied to the voltage frequency converter 12 via the reference voltage subtraction circuit 15. be.

The operation of the electromagnetic detection signal processing device 40 configured as described above will be explained below.

In the figure, a reference voltage V is applied to an electromagnetic detector 2 from a reference voltage power supply 10. is constantly applied, and the detection signal from the electromagnetic detector 2 is sent to the amplifier 1 via the reference voltage power supply 10.
1, and the output voltage of this amplifier 11 is applied to a reference voltage subtraction circuit 15 and becomes the reference voltage V of the reference voltage power supply 10.

By subtracting , the detection signal of the electromagnetic detector 2 is extracted (11) and input to the frequency converter 12. This detection signal is converted into a frequency by a voltage frequency converter 12, further integrated by an integral counter 13, and this value is inputted to an electronic computer 6 as count data shown in FIG.
It controls the Here of electromagnetic detector 2:
- To detect a single wire, a disconnection of the electromagnetic detector 2 is detected by applying the output voltage of the amplifier 11 to the voltage comparator 14 and comparing it with a certain voltage value VL. When a disconnection is detected, the disconnection detection bit setter 16 inputs data as shown in FIG. Let's do it. By inputting the disconnection detection bit shown in FIG. 6 to the electronic computer 16 together with the count data of the integration counter 13, the electronic computer 6 can always detect the disconnection of the electromagnetic detector 2. This makes it possible to determine the state of disconnection in each case, and thereby enables stable and reliable electromagnetic fluid control.

(12) FIG. 7 is a waveform diagram illustrating details of disconnection detection by the voltage comparator 14. In FIG. 7, the horizontal axis represents time T, and the vertical axis represents the output voltage of the amplifier 11. Here, the reference voltage of the reference voltage power source 1o is Vo, and the electromagnetic detector 2
Let the detection voltage of Vs be Vs. This voltage Vs has a voltage change range from VsMAX to -VsMr due to changes in the electromagnetic fluid.
If N, the output voltage V of the amplifier 11 is V ””V o + V s
・・・・・・It must be (1), ■. =■BM! N<V<■. 10VIIMAX...Self...
It varies within the range of (2).

Therefore, if the electromagnetic detector 2 is normal, the following equation holds true.

V>Vo Vl[--(3) Furthermore, when the electromagnetic detector 2 is disconnected, the input voltage to the amplifier 11 becomes zero, and the following equation holds: V=O..Group.(4).

Therefore, considering the drift voltage of the amplifier 11, etc.13), the comparison voltage Vr of the voltage comparator 14 is 0 < Vr,
<, V o Vl+MIN ° for -
By setting within the range (5), disconnection of the electromagnetic detector 2 can be detected. By detecting disconnection of the electromagnetic detector 2 in this manner, a stable and reliable electromagnetic fluid state monitoring device can be provided.

FIG. 8 is a block diagram showing another embodiment of the present invention.

In FIG. 8, the same components as those in the embodiment shown in FIGS. 1 and 5 are given the same reference numerals, and their explanations will be omitted. 8th
The embodiment shown in the figure differs from the embodiment shown in FIG. and 40B, and in these electromagnetic signal processing devices 40A and 40B, reference voltages Vom and Vom are constantly applied to each of the electromagnetic detectors 2 and 2B from the reference voltage power supply 10A and IOB, and the reference voltages Vom and Vom from the electromagnetic detectors are The detection signal is collected via the reference voltage power supply 10A and IOB (14), and the detected signal is sent to the voltage comparator 14.
A and 14B are compared with predetermined values, and based on the comparison result, it is possible to detect that the two electromagnetic detectors and 2B are disconnected, and at least one of the two electromagnetic detectors or 2B is
The point is that when it is detected that the electromagnetic detector 2B is disconnected, a detection signal from a source other than the electromagnetic detector 2B or the two persons is used as the position change amount signal of the electromagnetic fluid. Therefore, there is no change in other configurations.

The operation of the electromagnetic fluid condition monitoring device configured as described above will be explained with reference to the flowchart shown in FIG. Fluctuations in the electromagnetic fluid 1 are detected by two electromagnetic detectors and 2B, and this detection signal is input to an electromagnetic detection signal processing device 40 shown in FIG. Here, in the electromagnetic detection signal processing device 40, when it is detected that one of the two electromagnetic detectors or 2B is disconnected, the detection signal from the other electromagnetic detector 2B or two people is transferred to the electromagnetic fluid 1. The signal is input to the electronic computer 6 as a position change amount signal. That is, the electronic computer 6 is configured to be able to input the signals of the electromagnetic detection (15) and the signal processing device 40A or 40B, calculate the control amount for each control clock cycle from the control cycle clock generator 7, and Control device 5
The electromagnetic fluid control equipment 3 is controlled via the electromagnetic fluid control equipment 3. More specifically, as shown in FIG.
In step 10, the signals from the two electromagnetic detectors are input, and in step 111, it is determined whether or not the two electromagnetic detectors are disconnected. If it is normal, the process moves to step 112, and if it is determined that the wire is disconnected, The process moves to step 113.

In step 112, the positional deviation of the electromagnetic fluid 1 is calculated, and the process moves to step 114. And step 11
5, the control amount output is output to the electromagnetic fluid control device 5.

On the other hand, if it is determined in step 111 that there is a disconnection, the signal from the electromagnetic detector 2B is inputted in step 113, and the process moves to step 116.

In step 116, it is determined whether or not the electromagnetic detector 2B is disconnected, and if it is normal, the process moves to step 112. Further, in step 116, (16) if it is determined that the electromagnetic detector 2B is disconnected,
The process moves to step 117, and in step 117, an electromagnetic fluid emergency stop command is output to the electromagnetic fluid control device 5. By operating in this way, even if a disconnection of two electromagnetic detectors or 2B is detected during control of electromagnetic fluid, the control can be continued normally, and furthermore, even if a disconnection of two electromagnetic detectors or 2B is detected, the control can be continued normally. Or, if both of them are disconnected, the electromagnetic fluid 1 can be stopped immediately, and safe and reliable control can be performed.

In this way, the electromagnetic fluid state monitoring device of this embodiment can realize stable and highly reliable control.

FIG. 10 is a block diagram showing another embodiment of the present invention, and FIG. 11 is a block diagram showing an electromagnetic detection signal processing device used in this embodiment. In these figures, two electromagnetic detectors 2, two main electromagnetic detectors and a backup electromagnetic detector 2B, are provided, and a wake-up magnetic detection signal processing device 40 is provided.
0 is for the two electromagnetic detectors and 2B, and the reference voltage power supplies 10A and 1 provided for each two electromagnetic detectors or 2B.
・While always applying the reference voltages VoA and Von from 0.B (17), the detection signal from the electromagnetic detector 2 is taken in through the reference voltage power supply 10A and IOB, respectively, and the taken-in detection signal is The predetermined values provided for each of the two electromagnetic detectors and 2B are compared by the comparators 14A and 14B, respectively, and a disconnection of the electromagnetic detector 2 is detected based on the comparison result. When a disconnection is detected, the measurement signal system switch 20'lr: switches the detection signal from the electromagnetic detector 2B other than the two detectors to the voltage frequency as a signal for detecting the amount of position change of the electromagnetic fluid 1. In addition, when both the electromagnetic detectors 2 and 2B are disconnected, disconnection signals 200A and 200 from the comparators 14A and 14B are supplied to the converter 12.
00B is input and the electromagnetic fluid emergency stop command output circuit 21
The emergency stop command 250'i is configured to be output via the emergency stop command 250'i.

Further, the measurement signal system switch 20 usually includes a comparator 1
Convert only the amplifier output voltage from 4A to the voltage frequency converter 12
However, if a disconnection is detected in the comparator 14A (18), a switching signal is output to the signal system switch 20 to switch the signal system, and the amplifier output voltage from the comparator 14B is changed. Voltage frequency converter 12
It is designed to be input.

The signal from the measurement signal system switch 20 is frequency-converted by a voltage-frequency converter 12, integrated by a frequency counter 13, converted into a position signal of the electromagnetic fluid 1, and inputted to the computer 6. ing. Further, when a disconnection is detected from the voltage comparator 14A and the comparator 14B, these disconnection detection signals 200 and 200B are input to the electromagnetic fluid emergency stop command output circuit 15, and the electromagnetic fluid emergency stop command output circuit 15 outputs the electromagnetic fluid emergency stop command output circuit. An emergency stop command 250 is supplied to the fluid control device 5 to cause an emergency stop to the electromagnetic fluid 1 (il-).

The operation of the electromagnetic fluid condition monitoring device including the electromagnetic detection signal processing device configured as described above is shown in FIGS. 10 to 12.
This will be explained below with reference to the figures.

In the figure, the change in the position of the electromagnetic fluid 1 is simultaneously detected by two electromagnetic detectors and 2B, and (19) detection number 114 from these two electromagnetic detectors and 2B is input to the electromagnetic detection signal processing device 400. Ru.

The computer 5 inputs signal data from the electromagnetic detection signal processing device 400 and calculates a control amount every time it receives a control period clock signal from the control period clock generator 7,
The position of the electromagnetic fluid 1 is controlled via the electromagnetic fluid control device 5 and the electromagnetic fluid control equipment 3.

This can be explained using the flowchart shown in Figure 12.
In step 120, signals from two electromagnetic detectors are input. Next, in step 121, the positional deviation of the moving electromagnetic fluid 1 is calculated. Next, the entire position correction control amount of the electromagnetic fluid 1 is calculated and the process moves to step 123. In step 123, the control amount is output to the electromagnetic fluid control device 5. This is how it works. Therefore, as in the embodiment shown in FIG. 8, there is no need for the electronic computer 6 to determine whether the electromagnetic detector 2 is disconnected (see FIG. 9), and the control from the electromagnetic detection signal input to the electromagnetic fluid control device 5 is eliminated. The processing time required to output the amount can be shortened.

(20) Furthermore, the operation of the electromagnetic detection signal processing device 400 shown in FIG. 11 will be explained. The measurement signal system switch 20 normally supplies the voltage from the comparator 14A to the voltage frequency converter 12, but if a disconnection between the two electromagnetic detectors is detected in the comparator 14A, this measurement signal The system switch 20 is switched to transfer the output from the comparator 14B to the voltage frequency converter 1.
Supply to 2. As a result, the voltage frequency converter 12 converts the signal into frequencies, integrates these frequencies in the frequency counter 13, and outputs the integration result to the computer 6.

Furthermore, when the comparator 14A detects that the electromagnetic detector 2A is disconnected, the disconnection detection signal 200A is output to the electromagnetic fluid emergency stop output circuit 21. Then, due to the disconnection of two electromagnetic detectors, the switch 20
After switching, the electromagnetic detector 2B outputs a disconnection detection signal 2 when the comparator 14B similarly detects a disconnection.
When 00B is input to the electromagnetic fluid emergency stop output circuit 21, the electromagnetic fluid emergency stop output circuit 21 outputs the main (21
) We checked the disconnection detection signal I from the comparator 14A, and when both disconnection detection signals 200A and 200B were output, we confirmed that both electromagnetic detectors 2 and 2B were disconnected, and the electromagnetic fluid control An emergency stop command 250 is output to the device 5 and the electromagnetic fluid 1 is brought to an emergency stop.

As described above, the electromagnetic fluid condition monitoring device according to the present embodiment is more effective than the device shown in FIG. This has the advantage of being able to shorten the time until an emergency stop, and of protecting each equipment from damage caused by the runaway of the electromagnetic fluid 1 that occurs in a short period of time due to the instability peculiar to the electromagnetic fluid 1. . In the case of FIG. 8, the time required for processing by the computer 6 is approximately 1 ms, and according to this embodiment (FIGS. 10 and 11), the time required for processing is approximately 1 ms.
It is possible to shorten the control cycle by about 0 μs, and the control period of the entire device can be shortened by about 5%.

As described above, according to the present invention, it is possible to always detect a break in the electromagnetic detector, and furthermore, even if a break in the electromagnetic detector occurs during control of the electromagnetic (22) fluid, it is possible to control the electromagnetic fluid. This has the effect of providing a stable and reliable electromagnetic fluid condition monitoring device that can continue normally.

[Brief explanation of the drawing]

Fig. 1 is an overall system configuration diagram shown to explain the prior art, Fig. 2 is a processing flow chart shown to explain the prior art, Fig. 3 is a block diagram showing a conventional electromagnetic detection signal processing device, and Fig. 4 is a block diagram showing a conventional electromagnetic detection signal processing device. The figure shows the control operation of conventional technology +! f-
FIG. 5 is a block diagram showing the configuration of an electromagnetic detection signal processing device used in the electromagnetic fluid condition monitoring device according to the present invention, and FIG. An explanatory diagram showing the bit layout of data used for signal exchange, FIG. 7 is a time chart shown to explain the operating principle of the electromagnetic detection signal processing device shown in FIG. 5, and FIG. 8 is a diagram showing another embodiment of the present invention. An overall system configuration diagram showing an example, FIG. 9 is a flowchart shown to explain the operation of FIG. 8, and FIG. 10 is an overall system configuration diagram showing still another embodiment of the present invention. 10 is a block diagram showing the detailed configuration of the electromagnetic detection signal processing device used in FIG. 10, and FIG. 12 is a flowchart shown for explaining the processing operation in the divider shown in FIG. 10. 1... Electromagnetic fluid, 2 people and 2B... Electromagnetic detector,
3... Magneto fluid control equipment, 5... Magneto fluid control device, 6... Electronic computer, 7... Control cycle clock generator, 10... Reference voltage power supply, 11... Amplifier, 1
2... Voltage frequency converter, 13... Integration counter,
14... Voltage comparator, 15... Reference voltage calculation circuit,
4o and 400...electromagnetic detection signal processing device, 20o
...Disconnection detection signal, 250...Emergency stop command. (24) Kaya 305 2nd map Inumuga (solution standard - Chimo 7th amplified drinker 1J41L Nagine Kaya B eyes / Kayaq eyes Kaya / Q mouth

Claims (1)

[Claims] 1. An electromagnetic detector that detects the state of the electromagnetic fluid, and electromagnetic detection signal processing that captures the detection signal from the electromagnetic detector and detects the amount of position change of the electromagnetic fluid based on this detection signal. and a monitoring control device that monitors and controls the electromagnetic fluid based on an output signal from the electromagnetic detection signal processing device, wherein the electromagnetic detection signal processing device constantly applying a reference voltage from a reference voltage power source to the electromagnetic detector, and capturing a detection signal from the electromagnetic detector via the reference voltage power source,
A magnetic fluid state monitoring device characterized in that it is configured to compare the captured detection signal with a predetermined value and to determine a disconnection according to the comparison result. 2. An electromagnetic detector that detects the state of the electromagnetic fluid, a detection signal from this electromagnetic detector that completely fails, an electromagnetic detection signal processing device that detects the amount of position change of the electromagnetic fluid based on this detection signal, and In the electromagnetic fluid state monitoring device comprising a monitoring and control device that monitors and controls the electromagnetic fluid based on an output signal from the detection signal processing device, a plurality of the electromagnetic detectors are provided, and the electromagnetic detection signal processing device is provided with the electromagnetic detection signal processing device. A reference voltage is always applied to the electromagnetic detector from a reference voltage power supply, and a detection signal from the electromagnetic detector is taken in through the reference voltage power supply, and the taken-in detection signal is compared with a predetermined value. A disconnection determination is made according to the result, and when one of the electromagnetic detectors is disconnected, a detection signal from the other electromagnetic detector is used as a signal for detecting the amount of change in position of the electromagnetic fluid. Electromagnetic fluid condition monitoring device. 3. In the electromagnetic fluid condition monitoring device according to claim 2, the electromagnetic detection signal processing device includes a reference voltage power supply that supplies a reference voltage to each of the plurality of electromagnetic detectors, and a reference voltage power supply that supplies the reference voltage to each of the plurality of electromagnetic detectors, and An amplifier that takes in and amplifies the detection signal from each electromagnetic detector, a plurality of comparators that compares the signals from these amplifiers with a predetermined value provided for each electromagnetic detector, and electromagnetic detection using the comparison signal from the comparator. a switching device that supplies a signal from an electromagnetic detector other than the electromagnetic detector to the voltage frequency converter when a disconnection of the device is detected; an integral counter that integrates the signal from the voltage frequency converter; An electromagnetic fluid state monitoring device comprising: an emergency stop command output circuit that outputs an emergency stop command when all comparison output signals from the comparator are disconnected.