JPH0334162Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pressure measuring device for measuring cerebral pressure, blood pressure, etc.

[Conventional technology]

In this type of pressure measuring device, a zero balance operation of the pressure amplifier must be performed on the transmitting side before starting measurement. Conventionally, when the automatic balance switch for this purpose was pressed, a digital counter in the offset addition circuit started counting, and the count value was converted to an analog voltage via a D/A converter and sent to the pressure amplifier (2 inputs). It outputs the difference between the offset (error voltage) of the voltage transducer applied to one input and applied to the other input of the voltage amplifier and a sequentially increasing analog voltage (balancing offset voltage). A comparator is connected to the output side of the pressure amplifier, which compares the output of the pressure amplifier with 0 voltage, and determines when the output of the pressure amplifier is 0.
When the voltage matches, it stops the counter and returns to zero.
Finish the balance movement. That is, the offset voltage from the offset adding circuit cancels out the offset of the voltage transducer.

Therefore, this offset voltage will inevitably be transmitted to the receiving side as is.

[Problem that the invention attempts to solve]

The offset signal transmitted during the above-mentioned balance operation is unnecessary for pressure measurement, and if the receiving side records it on a recorder or trend graph, unnecessary and meaningless signals may be written. It will be. Therefore, conventionally, the transmitting side has either masked the offset signal (ie, dropped it to zero) during the balance operation, or done nothing and output the unnecessary signal as it is.

Therefore, the present invention attempts to solve the above-mentioned problems.

[Means for solving problems]

The present invention is designed to block the transmission of unnecessary offset signals during balance operation and to transmit a calibration signal instead.

[Effect]

Unnecessary signals will no longer be recorded, and instead meaningful calibration signals will be automatically recorded before starting the measurement.

〔Example〕

FIG. 1 is a block diagram showing an example of a pressure amplifier section used in the present invention. In the figure, the part surrounded by the broken line is the part added according to the present invention, and SW
1 indicates an automatic balance switch, and SW2 indicates a changeover switch. If there is no broken line, when the automatic balance switch SW1 is pressed, the offset voltage from the offset addition circuit is output as is, as in the conventional case. The changeover switch SW2 switches the signal path from the pressure amplifier output side to the calibration signal generation circuit output side during balance operation.
is configured to be linked to the closing of the Further, the calibration signal generating circuit is configured to operate simultaneously with the operation of the offset adding circuit. Since designing such a circuit is easy for those skilled in the art, detailed explanation will be omitted.

Before starting the measurement, the automatic balance switch
When SW1 is pressed, the counter in the offset addition circuit starts counting, and in synchronization with this, the changeover switch SW2 is switched to the calibration signal generation circuit side. At the same time, the offset addition circuit begins to apply a balancing offset voltage to the pressure amplifier, and at the same time activates the calibration signal generation circuit. Therefore, during the balance operation, the offset voltage is cut off and only the calibration signal is transmitted from the calibration signal generation circuit to the receiving side via the appropriate transmission circuit. When the balance movement is finished,
The counter in the offset circuit stops, and in synchronization with this, the changeover switch SW2 is switched to the pressure amplifier side. Therefore, the calibration signal is recorded on the receiving side before the start of measurement, making it possible to check the transmission system and measurement system, and unnecessary offset signals are not written. Furthermore, on the receiving side, it can be confirmed that the balance operation is in progress, for example, by displaying a calibration signal on the cathode ray tube surface. Furthermore, simply blocking the offset signal does not allow the remote receiving side to know that a balancing operation is in progress.

FIG. 2 is a block diagram showing an embodiment of the present invention in which a multi-channel pressure measuring device is constructed using the pressure amplifier section of FIG. 1. Although the illustrated example uses three channels, wireless and wired transmission paths, either one may be used. Although the receiver is equipped with a cathode ray tube and a recording device, the cathode ray tube may be omitted in some cases.

Further, in the above example, the changeover switch SW2 and the calibration signal generation circuit are provided in the pressure amplifier section, but they may be provided in other parts of the transmitter.

In the above example, the changeover switch SW2 is switched in synchronization with the counter in the offset adding circuit, but other methods may be used as long as they are linked to the balance operation.

[Effect of idea]

According to the present invention, the following practical effects can be obtained.

(a) Since no unnecessary offset signals are transmitted during zero balance operation, meaningless signals are not recorded.

(b) Since the calibration signal is transmitted using the zero balance operation, there is no need to perform a new calibration operation.

(c) By looking at the calibration signal displayed on the receiving side, it can be confirmed that balance is being operated on the transmitting side.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a pressure amplifier section used in the present invention, and FIG. 2 is a block diagram showing an embodiment of the present invention using the pressure amplifier section of FIG. SW1...Automatic balance switch, SW2...Means for switching the signal path during zero balance operation.

Claims (1)

[Scope of utility model registration request] On the transmitting side, there is an offset adding circuit that applies a zero balance offset voltage to the pressure amplifier, a calibration signal generating circuit that operates simultaneously with the operation of the offset adding circuit, and a signal path that applies the above voltage while the offset adding circuit is operating. The pressure measuring device is provided with means for switching from the amplifier output side to the output side of the calibration signal generation circuit, so that only the calibration signal is received on the receiving side while the offset addition circuit is operating.