JPH1144712A - Input acquiring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an input acquiring device capable of coping with mixed inputs for resistance measurement and voltage measurement with a simple structure. SOLUTION: This input acquiring device is provided with a terminal board having measuring terminals t11, t12, t13,...tn1, tn2, tn3, using all of three terminals or all of four terminals when resistance input signals Pt1, Pt2 are measured, and using only two terminals when voltage input signals E1, E2 are measured, a processing means CPU receiving a voltage input signal from a measuring terminal as it is and receiving a resistance input signal while a fixed current is fed to the measuring terminal and converted into a voltage when each input signal is received, and a judging means D judging whether the input is a resistance input or a voltage input based on the presence or absence of the current flowing on each measuring terminal when the fixed current is fed to each measuring terminal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input receiving device for receiving a plurality of input signals.

[0002]

2. Description of the Related Art When a plurality of input signals are captured by a measuring device, a recorder, a data acquisition device, and the like, a measuring circuit and a measuring process corresponding to the type of the input signal are required. Conventionally, for example, all of the measurement terminals on the terminal board are configured to be able to connect only the same type of input signal, or a specific measurement terminal is connectable to a voltage input signal, and another specific measurement terminal is connected to a resistance input signal. Can be connected to support mixed input.

[0003]

For this reason, it is difficult to flexibly cope with various mixed inputs. In addition to switching input signals, input types must be switched, and the switching circuit is complicated. It became expensive and it was difficult to connect any input to any measurement terminal. Also, if mixed input is to be enabled, it is necessary to know in advance which measurement terminal is which type of input, and to set and register it for measurement calculation, etc., which makes the operation complicated. , Incorrect settings, and malfunctions.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide an input receiving device which has a simple configuration and can cope with mixed input of resistance measurement and voltage measurement.

[0005]

SUMMARY OF THE INVENTION The present invention has a measuring terminal composed of three or four terminals for each of a plurality of input signals, and uses all three terminals or all four terminals when measuring a resistance input signal. A terminal board that uses only two terminals when measuring a voltage input signal, and a voltage input signal is taken from the measurement terminal as it is when taking in each input signal, and a constant current is supplied to the measurement terminal for a resistance input signal and converted to voltage. An input capturing device, comprising: a processing unit that captures a current; and a determination unit that determines whether a resistance input or a voltage input is present based on the presence or absence of a current flowing through each measurement terminal when a constant current is supplied to each measurement terminal. It is.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram showing the configuration of an embodiment of an input capturing device according to the present invention. In FIG. 1, E
1, En indicate voltage input signals such as thermocouples, and Pt1, Pt
t2 indicates a resistance input signal of a three-wire type resistance temperature detector or the like. t
11, t12, t13,..., Tn1, tn2, and tn3 are three terminals, each of which is a set of measurement terminals to which a voltage input or resistance input signal is connected, for example, three terminals for each of a plurality of input signals as shown in FIG. And a terminal plate T having the measuring terminals configured as described above. That is, in the voltage input, two first and second terminals t11, t12,..., Tn1, tn2
And three terminals t21, t22, t23, t31 and t31 including the third terminal in the resistance input.
At 32, t33,..., Three lead wires of a resistance temperature detector are connected and used.

Each of S1,..., Sn is a pair of switches, which are sequentially switched by a command of a control circuit CC described later, and among the measurement terminals, in particular, first and second terminals t11, t11,.
An input switch for taking in signals from t12,..., tn1, tn2, IS is a constant current I1, I2 for measurement of a constant current circuit.
Is a current supply switch for supplying a resistance input signal based on a command from the control circuit CC, A is an amplifier that can change the gain to G1 or G2 according to a command from the control circuit, and AD is an A / D converter.

M is a memory for storing an operation program, the type of input signal for each measurement terminal, processing / operational expressions, etc.
The CPU computes the measurement data according to the contents of the memory M and outputs the processed data (μCPU
A control circuit for issuing a command signal such as taking in of an input signal, switching the gain of an amplifier A, and starting conversion of an A / D converter AD in accordance with a command from the processing means CPU;
P is a display for digitally displaying the processed data, displaying an analog trend graph, and the like, and P is a printer for digitally printing and analog recording the measured processing data.
When a constant current is supplied to each measurement terminal via the constant current supply switch IS, D is a resistance R0 among the measurement terminals.
, Tn connected to the ground G via the
3 is a determining means for determining whether the input is a resistance input or a voltage input based on the presence or absence of a current flowing through 3.

The operation of the input capture device used in the data acquisition device, the recording device and the like configured as described above will be described. Before starting the measurement, it is necessary to know whether the input signal connected to each measurement terminal is a voltage input or a resistance input. Therefore, the constant current supply switch IS is operated by operating a setting device (not shown).
Are turned on, and the switches of the switches S1,..., Sn are sequentially driven, and the measurement terminals t11, t12, t13,.
1, tn2, tn3 are supplied with a constant current, and the determination means D determines whether there is a resistance input or a voltage input based on the presence or absence of a current flowing through each measurement terminal. For example, channel No. When a current is supplied to the first measurement terminals t11, t12, and t13, the third terminal t13 is open and no current flows to the ground G, so that no voltage is generated in the resistor R0, and the determination means D detects the current. At this time, it is determined that the input is not a resistance but a voltage, and this determination signal is transmitted to the processing means CPU, and the channel No.
1 stores the voltage input in the memory M.

For example, for example, the channel No. When a current is supplied to the second measurement terminals t21, t22, and t23, the third terminal t23 is used and connected to the ground G, and the current flows through the resistor R0 to generate a voltage.
Detects the current, determines at this time that the input is a resistance input instead of a voltage input, and transmits this determination signal to the processing means CPU. 2 stores the voltage input in the memory M. This is repeated, and the types of input of all points are stored in the memory M.

When determining the resistance input, the determination means D can determine the magnitude of the resistance of the resistance input from the magnitude of the detected voltage. For example, if the supply current is 1 mA, and the input resistances are 10Ω, 100Ω, and 1000Ω, the voltage drops are 10 mV, 100 mV, and 1000 mV, respectively. Can be used to determine the magnitude and type of the resistance value.

At this time, all the measuring terminals are in the same state. In the case of a voltage input signal, two terminals are used as + and-in the terminal plate T of FIG. 2, and in the case of a resistance input signal, all three terminals are used. However, in this case, any input signal can be connected to any measurement terminal and commonly used. Further, the setting device may store necessary detailed information of each measurement terminal in the memory M.

When the above setting operation is completed, the state is switched to the measurement state, and the input operation and the measurement operation are started. Memory M
Processing means C according to the operation program stored in
The PU issues a command to the control circuit CC, and the control circuit CC outputs a command signal C1 based on the command, and turns on the input switch S1. At this time, the measurement terminal No. Since the input signal of No. 1 is the voltage input signal E1, the current supply switch IS is not driven by the command signal C1 and holds the off state.
Thus, the voltage input signal E captured by the input switch S1
1 is amplified by an amplifier A switched to a predetermined gain G1 by a command signal C2 of a control circuit CC, and its output is input to an A / D converter AD, and at the same time, A is amplified by a command signal C3 of the control circuit CC. / D conversion is started. The measurement data converted into a digital signal by the A / D converter AD is sent to the processing means CPU and linearized according to the type of the input signal (the type of thermocouple, etc.) according to the program stored in the memory M. And the like are sent to the display DP and the printer P, and the measurement terminal No. One measured value is displayed and recorded in digital and analog.

Next, according to the program in the memory M, the command signal C1 of the control circuit CC turns off the input switch S1 and turns on the input switch S2. At this time, the measurement terminal No. Since the input signal of No. 2 is the resistance input signal Pt1, the current supply switch IS is driven by the command signal C1 to be turned on. Therefore, the constant currents I1 and I2 are supplied to the resistance input signal Pt1, and a voltage corresponding to the resistance value is supplied to the amplifier A. At this time, the gain of the amplifier A is switched to G2 by the command signal C2 of the control circuit CC. The output amplified by G times by the amplifier A is converted into a digital signal by an A / D converter AD, and is subjected to predetermined processing by a processing means CPU according to a program stored in a memory M. Sent to the printer P, and the measurement terminal No. The measured value of 2 is displayed in digital and analog.
Be recorded.

In the same manner, the measurement terminal No. 3 to N
o. The same operation as described above is repeated for n, and a large number of input signals are taken in and measurement is performed. The resistance measurement may be performed by any method, and may be performed by a one-current method in addition to the two-current method described above. In addition, the current flowing to each measurement terminal for type determination may be a dedicated separate current. The position of the determination means D may be any position as long as it can be measured on the downstream side of the current path, and may be any means. Alternatively, the determination means D may determine whether there is a resistance input or a voltage input based on the presence or absence of a current flowing from the upstream constant current circuit. That is, in the voltage input, even if the power supply switch IS is turned on, the current cannot flow to the measurement terminal side, and the current can flow in the resistance input, and this may be detected.
Alternatively, the measurement may be performed such that a current is always supplied without providing a power supply switch.

In the above example, the three-wire type resistance measurement has been described, but the same applies to the four-wire type as shown in FIG.
That is, four terminals tm1, tm for each of the plurality of input signals.
2, tm3, tm4, ..., ti1, ti2, ti3, t
i4 having a measuring terminal composed of a resistance input signal Pti
All four terminals tm1, tm2, tm3 and tm4 are used for measurement, and only two terminals are used for measuring the voltage input signal Ei. When taking in each input signal, the resistance input signal P
For ti, the respective switches of the switch Sm are turned on to supply the constant current I from the constant current circuit to the resistor Ptm via the measuring terminals tm1 and tm4, convert the voltage into a voltage, and take in the voltage input signal Ei. Are turned on, the signals are taken from the measuring terminals ti2 and ti3 as they are, amplified by the amplifier A, and measured in the same manner as in FIG.

Prior to measurement, when a constant current I is supplied from a constant current circuit to each measurement terminal, whether there is a current flowing through each measurement terminal is used to determine whether the input is a resistance input or a voltage input, and the magnitude of the resistance is determined. Determine with D. At this time, the presence or absence of the current flowing from the fourth terminal to the ground G via the resistor R0 may be detected, or the determination may be made based on the presence or absence of the current flowing from the constant current circuit. Others are the same as FIG.

[0018]

As described above, the present invention has three or four measurement terminals for each of a plurality of input signals, and uses all three or four terminals when measuring a resistance input signal. When measuring a voltage input signal, a terminal board that uses only two terminals, and when capturing each input signal, the voltage input signal is directly captured from the measurement terminal, and for the resistance input signal, a constant current is supplied to the measurement terminal and converted to voltage. Processing means, and a determination means for determining whether a resistance input or a voltage input based on the presence or absence of a current flowing through each measurement terminal when a constant current is supplied to each measurement terminal. Device. Therefore, regardless of whether a voltage input or a resistance input is connected to the measurement terminal, the type can be automatically determined by the determination means and the magnitude of the resistance can be determined, so that the measurement terminal can be shared. It is possible to easily cope with mixed input of resistance input and voltage input with a simple circuit device. Further, by supplying a constant current for resistance measurement to the measurement terminal and using the constant current as the type determination current, it is not necessary to add a special current source, so that downsizing and simplification can be achieved.
Also, by storing the determined type in a memory and using it,
There is no need to know in advance which measurement terminal is what type of input, and there is no need to make settings.
There will be no erroneous settings. Further detailed settings can be semi-automatically set by additionally setting detailed information.
In addition, it is possible to know an erroneous wiring by comparing with the actually intended wiring based on the information of the determination means.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing one embodiment of the present invention.

FIG. 2 is a configuration explanatory view showing one embodiment of the present invention.

FIG. 3 is a configuration explanatory view showing one embodiment of the present invention.

[Explanation of symbols]

E1, En, Ei Voltage input signal Pt1, Pt2, Ptm Resistance input signal I1, I2, I Constant current T Terminal plate t11, t12, t13 to tn1, tn2, tn3 Measurement terminal S1 to Sn Switch IS Power supply switch A Amplifier CC control circuit AD A / D converter CPU processing means D discriminating means G ground

Claims (5)

[Claims] 1. A measuring terminal comprising three or four terminals for each of a plurality of input signals, all three terminals or all four terminals are used when measuring a resistance input signal, and only two terminals are used when measuring a voltage input signal. And a processing means for supplying a constant current to the measuring terminal for a voltage input signal as it is, and for converting a voltage into a voltage for the resistance input signal, An input capturing device comprising: a determination unit configured to determine whether a resistance input or a voltage input is performed based on the presence or absence of a current flowing through each measurement terminal when a constant current is supplied to the terminal. 2. The method according to claim 1, wherein the determining means determines whether a resistance input or a voltage input is present based on the presence or absence of a current flowing through each measurement terminal when a constant current for measurement is supplied to each measurement terminal via a constant current supply switch. The input capture device according to claim 1, wherein: 3. The determination means determines whether the input is a resistance input or a voltage input based on the presence or absence of a current flowing through a third terminal or a fourth terminal used for the resistance input among the measurement terminals or the presence or absence of a current flowing from a constant current circuit. 2. The method according to claim 1, wherein
Or the input capture device according to claim 2. 4. The input device according to claim 1, wherein said determining means determines the magnitude of the resistance of the resistance input from the magnitude of the detection voltage when determining the resistance input. Capture device. 5. An input device according to claim 1, further comprising a memory for storing a type of each input signal connected to said measuring terminal in accordance with a determination signal of said determination means. Device.