JP3856806B2 - Valve positioner, valve drive device - Google Patents

Description

  The present invention relates to a valve positioner that controls an operating angle of a valve and a valve drive device that performs opening / closing drive of the valve, and more particularly to a valve positioner that can easily perform zero span setting and a valve drive device including the valve positioner.

A valve driving device is used to open and close valves such as butterfly valves and ball valves for controlling the flow rate of liquid and gas. This valve drive device is roughly constituted by a motor that drives a valve and a valve positioner that is a controller that controls the motor.
Specific examples of such a valve driving device are shown in, for example, Patent Document 1 and Patent Document 2, and generally a function of inputting a setting signal for setting the operating angle of the valve from an external device such as a PID controller. And a function of detecting the operating angle of the valve, and a function of controlling the driving of the valve (controlling the motor) by comparing the setting signal and the detection signal. Further, there are some which have a function of outputting the detection signal (signal corresponding to the detection angle) in accordance with a predetermined signal standard (hereinafter, the output signal is referred to as an output detection signal). Here, the output detection signal is used to display the operating angle of the valve in an external device.
When the valve and the valve driving device are assembled, the maximum value and the minimum value of the setting signal input in accordance with a predetermined signal standard are respectively set to the fully open position and the fully closed position of the valve. The zero-span setting of the valve positioner is performed so as to be associated. Similarly, zero span setting is performed for the output detection signal so that the level corresponds to the signal standard. Usually, the signal standards of the setting signal and the output detection signal are the same.

For example, when the signal standard is a current signal of 4 to 20 mA (zero value 4 mA, span value 16 mA), the zero span setting for the setting signal is performed when 4 mA (zero value) is input as the setting signal. It is recognized that the valve is fully closed, and the zero value and the span value are set so that when 20 mA is input, it is recognized that the valve is fully opened.
Similarly, in the zero span setting for the output detection signal, the output detection signal of 4 mA is output when the valve is fully closed, and the output detection signal of 20 mA is output when the valve is fully open. Thus, the zero span setting is made.

Hereinafter, a schematic configuration of the conventional valve positioner B and a procedure for setting the zero span will be described with reference to FIGS. 3 and 4.
FIG. 3 is a block diagram showing a schematic configuration of a valve driving device Y including a conventional valve positioner B having a function of outputting the output detection signal.
As shown in FIG. 3, the valve driving device Y includes a motor 4 for driving a valve (not shown) and a valve positioner B for controlling the motor 4.
The motor 4 is connected to the drive shaft of the valve, and the valve positioner B controls the opening (operation angle) of the valve by controlling the drive of the motor 4.
In the valve positioner B, a setting signal corresponding to the setting angle (target angle) of the valve is input to the setting value input circuit 1 from an external device such as an angle setting device (not shown). The setting signal input to the setting value input circuit 1 is converted into a digital signal by the A / D converter 2 a and input to the determination circuit 3.
On the other hand, the operating angle feedback signal generator 5 connected to the output shaft of the motor 4 detects the current operating angle of the valve, and the detection signal of the signal level corresponding to the operating angle is sent through the feedback input circuit 6. The signal is input to an A / D converter 2b different from the A / D converter 2a and converted into a digital signal. The detection signal converted into a digital signal is input to the determination circuit 3.

Further, the valve positioner B includes an EEPROM set value storage circuit 7 in which zero span setting information (zero value and span value) regarding the set signal and the detection signal as described above is stored. Each of the signal and the setting signal is converted based on the zero-span setting information stored in the EEPROM setting value storage circuit 7, and control of the driving torque of the motor 4 (ie, driving) so as to reduce the difference between the conversion results. Power control).
The detection signal input to the determination circuit 3 is output to the D / A converter 9 and converted to the output detection signal which is an analog signal. The output detection signal is output to the outside, for example, a display panel or a controller for displaying the current valve operating angle by the opening output circuit 10.

FIG. 4 is a flowchart showing each procedure of the zero span setting for the setting signal and the zero span setting for the detection signal and the output detection signal in the conventional valve positioner B. In the following, S1, S2,... Represent procedure (step) numbers.
In the valve positioner B, the zero span setting for the setting signal is performed according to the procedure shown in FIG. Hereinafter, the valve operating angle fully closed position is associated with the signal level 4 mA of the setting signal, and the range from the valve fully closed position to the fully open position is associated with the setting signal span (16 mA). Will be described.
First, a signal generator is attached to the input terminal of the set value input circuit 1 (S1), the signal level of the signal generated by the signal generator is adjusted to 4 mA (S2), and the signal standard (4 to 4) of the set signal is adjusted. The signal adjusted to the minimum signal level (20 mA) (4 mA signal, hereinafter referred to as a reference signal) is input to the set value input circuit 1 (S3). Thus, the reference signal is converted into a reference signal value (digital value) corresponding to the signal level by the A / D converter 2 a and input to the determination circuit 3. In this state, when a predetermined setting signal zero value registration operation is performed on a registration switch (not shown) provided on the operation panel or the like of the valve driving device Y, the registration switch circuit 11 connected to the registration switch A setting signal zero value registration command is output to the determination circuit 3, and the reference signal value (digital value) corresponding to the signal level 4 mA of the reference signal is set as the zero value corresponding to the valve fully closed. It is stored in the value storage circuit 7 (S4).
Next, the signal level of the signal generated by the signal generator is adjusted to a maximum signal level of 20 mA in the signal standard of the setting signal (S5), and the signal (20 mA signal, hereinafter referred to as the maximum signal) Input to the set value input circuit 1 (S6). As a result, the maximum signal is converted into a maximum signal value (digital value) corresponding to the signal level by the A / D converter 2 a and input to the determination circuit 3. In this state, when a predetermined setting signal span value value registration operation is performed on the registration switch, a setting signal span value registration command is output from the registration switch circuit 11 connected to the registration switch to the determination circuit 3. The difference obtained by subtracting the zero value (reference signal value) stored in step S3 from the maximum signal value (digital value) corresponding to the signal level of 20 mA of the maximum signal is the fully closed to fully opened state of the valve. Is stored in the EEPROM set value storage circuit 7 as a span value corresponding to the range (S7).

On the other hand, FIG. 4B shows a procedure for setting a zero span for the detection signal and the output detection signal.
First, the user manually closes the operating angle of the valve (S101). As a result, the detection signal at the minimum level corresponding to the fully closed state of the valve is output by the operating angle feedback signal generator 5, and the signal value (digital value) of the detection signal at the minimum level is sent to the determination circuit 3. The output detection signal whose signal value is converted into an analog signal is output through the opening degree output circuit 10 while being input. In this state, when a predetermined detection signal zero value registration operation is performed on the registration switch, a detection signal zero value registration command is output from the registration switch circuit 11 to the determination circuit 3, and the detection signal of the minimum level is detected. The signal value (digital value) is stored in the EEPROM set value storage circuit 7 as a zero value of the detection signal corresponding to the valve fully closed (S102).
In this state, a current measuring device is connected to the output terminal of the opening output circuit 10 (S103), and the detection value by the current measuring device is the minimum level in the signal standard (4 to 20 mA) of the output detection signal. The zero value adjustment knob (not shown) connected to the opening degree output circuit 10 is operated and adjusted so as to be (4 mA) (S104). The zero value adjusting knob is connected to a signal level adjusting circuit 10a provided in the opening output circuit 10, and the level adjusting function of the signal level adjusting circuit 10a is used to control the zero value adjusting knob according to the operation of the zero value adjusting knob. The signal level (zero value) of the output detection signal (hereinafter referred to as the output reference detection signal) is adjusted (set).

Next, the user manually opens the valve operating angle (S105). As a result, the detection signal of the maximum level is detected by the operating angle feedback signal generator 5, and the signal value (digital value) of the detection signal of the maximum level is input to the determination circuit 3, and further the signal value The output detection signal converted into an analog signal is output through the opening degree output circuit 10. In this state, when a predetermined detection signal span value registration operation is performed on the registration switch (not shown) connected to the registration switch circuit 11, the registration switch circuit 11 sends a detection signal span value to the determination circuit 3. A difference obtained by subtracting the zero value (reference detection signal value) stored in step S102 from the maximum detection signal value corresponding to a state where the registration command is output and the valve is fully opened is the valve fully closed. Is stored in the EEPROM set value storage circuit 7 as the span value of the detection signal corresponding to the fully open range (S106).
Further, in this state, the detection value by the current measuring device connected to the output terminal of the opening output circuit 10 is the maximum level (20 mA) in the signal standard (4 to 20 mA) of the output detection signal. The span value adjustment knob (not shown) connected to the opening output circuit 10 is operated and adjusted (S107). The span value adjusting knob is also connected to the signal level adjusting circuit 10a. The level adjusting function of the signal level adjusting circuit 10a allows the minimum level (output) of the output detection signal according to the operation of the adjusting knob. The range (span) from the reference detection signal level) to the maximum level is adjusted (set).
By the above operation, the EEPROM set value storage circuit 7 stores the zero value and the span value for the set signal and the zero value and the span value for the detection signal. Further, the state of the opening output circuit 10 so that the output detection signal is correctly output at a level (4 to 20 mA) according to the signal standard according to the operating angle in the range from fully closed to fully opened of the valve. Is set. Thus, the opening degree output circuit 10 adjusts the detection signal to a signal of a predetermined signal standard (here, a current signal of 4 to 20 mA).
JP 2002-315372 A JP 2001-349457 A

However, the conventional valve positioner B as described above has a problem that a relatively expensive signal generator is required for the zero span setting of the setting signal, resulting in an increase in the number of equipment and equipment cost. In addition, there is a problem that a zero span setting can only be made by a person who has mastered the handling of signal generators.
Therefore, the present invention has been made in view of the above circumstances, and the object of the present invention is to provide a valve that can easily set a zero span for the setting signal without requiring a special device such as a signal generator. It is an object of the present invention to provide a positioner and a drive device for driving a valve including the positioner.

In order to achieve the above object, the present invention has a function of adjusting the current valve operating angle to a predetermined signal form (signal standard), and based on the adjusted signal (hereinafter referred to as an adjusted signal), It is configured as a valve positioner capable of setting a zero span of a valve operating angle setting signal input from the outside in the same signal form. Here, the adjustment function of the detection signal is a valve for outputting the detection signal in the form of a predetermined signal (for example, a current signal of 4 to 20 mA) as the detection signal for external output described in the prior art. This is a function that the positioner normally has.
Thereby, when the zero span setting of the setting signal is performed using the adjusted signal, the zero span setting of the setting signal can be performed without using a special device such as a signal generator. Therefore, even if it is not a master of the handling of a signal generator, the zero span setting of the said setting signal can be performed simply.

Here, the signal that is switched between the post-adjustment signal (that is, the output detection signal) and the setting signal input from the outside in the same signal form to be transmitted to one signal transmission path A switching function is provided, and the adjusted signal is input to the zero span setting unit for setting the zero span through the one signal transmission path, and the setting signal is operated by the valve through the one signal transmission path. As an example, it may be input to a control unit that controls the angle.
The valve positioner does not need to perform zero span setting and normal control at the same time. Therefore, if the signal input to the control unit that controls the operating angle of the valve is switched via the one signal path by the switching input function, a simpler configuration can be realized.
For example, when both the control of the valve operating angle and the zero span setting of the setting signal are processed by a single processing device (such as a microprocessor), only one signal input terminal of the processing device is consumed. It can be. Also, normally, the control of the valve operating angle and the zero span setting are processed based on the signal digitized by the A / D converter, and therefore the A / D converter is placed on the one signal transmission path. Is provided, the A / D converter also serves to digitally convert the adjusted signal and the setting signal, and there is no need to use a plurality of A / D converters.

It is also conceivable to detect whether or not the values set as the zero value and the span value of the detection signal are within a predetermined range and output the detection result. As a result, for example, when a zero value is set with the valve fully open or close to it, a situation in which a zero value or a span value is about to be set for a level of the detection signal that cannot be considered normally is worked. Can prevent the abnormal zero-span setting.
Similarly, it is conceivable to detect whether or not the values set as the zero value and the span value of the setting signal are within a predetermined range, respectively, and output the detection result. Thus, for example, when an unadjusted output detection signal is input instead of the setting signal and an attempt is made to set the zero value or span value of the setting signal, the level is not considered normally. Based on the signal, the operator can be notified of the situation where the zero value and span value of the setting signal are about to be set, and abnormal zero span setting can be prevented beforehand.
Furthermore, the present invention may be understood as a valve driving device including an actuator such as a motor for driving the valve to open and close, and the valve positioner for controlling the actuator.

According to the present invention, it is not necessary to use an expensive signal generator for setting the zero span for the setting signal, and the number of equipment and equipment cost can be reduced. In addition, even if you are not a master of signal generator handling, zero span setting is possible, and the setting work is simplified.
Also, if the zero value and the span value set for the detection signal and the setting signal are detected within the predetermined range and the result is output, abnormal zero span setting can be prevented beforehand.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
FIG. 1 is a block diagram showing a schematic configuration of a valve driving device X provided with a valve positioner A according to an embodiment of the present invention, and FIG. 2 shows a procedure for setting the zero span in the valve positioner A according to the embodiment of the present invention. FIG. 3 is a block diagram showing a schematic configuration of a valve driving device Y provided with a valve positioner B according to a conventional example, and FIG. 4 is a flowchart showing a procedure for setting a zero span in the valve positioner B. In addition, the same code | symbol is used about the structure similar to a prior art example.

FIG. 1 is a block diagram showing a schematic configuration of the valve driving device X including a valve positioner A according to an embodiment of the present invention.
A valve drive device X including a valve positioner A according to the embodiment of the present invention shown in FIG. 1 controls a motor 4 (an example of an actuator) connected to a drive shaft of a valve (not shown) and its drive. The valve positioner A is provided, and the opening degree (operation angle) of the valve is controlled by controlling the driving of the motor 4.

  The valve positioner A, like the valve positioner B in the conventional example, is a set value input circuit 1 to which a setting signal for setting the operating angle of the valve is input from an external device, and the setting signal that is an analog signal is a digital signal. An A / D converter 2a for converting to a signal, an operating angle feedback signal generator 5 for detecting a current valve operating angle and outputting a detection signal having a signal level corresponding to the operating angle, and the detection signal is input. Feedback input circuit 6, an A / D converter 2b for converting the detection signal (analog signal) input through the feedback input circuit 6 into a digital signal, the setting signal converted into a digital signal, and the detection signal And a determination circuit 3 that outputs a control signal of the motor 4 according to the difference, the setting signal and the detection signal. An EEPROM set value storage circuit 7 for storing a zero value and a span value for each signal, a motor drive circuit 8 that actually drives the motor 4 according to the control signal, and the A / D converter 2b A D / A converter 9 that converts the detection signal converted into a digital signal by the above into an output detection signal that is an analog signal, and an opening output circuit 10 that outputs the output detection signal to the outside (detection signal adjustment) An example of a unit) and a registration switch circuit 11 that is a circuit that causes the determination circuit 3 to execute processing for storing the zero value and the span value for the setting signal and the detection signal in the EEPROM setting value storage circuit 7. And have. Here, the determination circuit 3 and the registration switch circuit 11 are an example of means that doubles as a detection signal zero span setting means and a setting signal zero span setting means.

The setting signal and the output detection signal comply with a predetermined signal standard (signal form), and in this embodiment, the signal standard is 4 to 20 mA.
The opening output circuit 10 is configured so that the output detection signal changes in the range of 4 mA to 20 mA in accordance with the signal standard as the valve operating angle changes in the range from fully closed to fully open. A signal level adjustment circuit 10a having a zero-span setting function (level adjustment function) of the output detection signal output externally is provided.
Note that even if the signal standard is another standard such as 1 to 5 V, the applicability of the present invention is not affected.
The signal level adjustment circuit 10a is connected to a zero value adjustment knob (not shown), and the level adjustment function of the signal level adjustment circuit 10a is used for the output of the minimum level according to the operation of the zero value adjustment knob. A signal level (zero value) of a detection signal (hereinafter referred to as an output reference detection signal) is adjusted (set). Similarly to the zero value adjustment knob, the signal level adjustment circuit 10a is connected to a span value adjustment knob (not shown), and the output detection signal is output in accordance with the operation of the span value adjustment knob. The range (span) from the minimum level to the maximum level is adjusted (set).
Thus, the opening output circuit 10 (detection signal adjusting means) uses the level adjusting function of the signal level adjusting circuit 10a to convert the output detection signal (valve operating angle detection signal) to a predetermined signal standard. It can be adjusted to a 4 to 20 mA current signal (predetermined signal form) and output to the outside.

The registration switch circuit 11 is connected to a registration switch (not shown). By operating the registration switch, the zero value and the span value for the setting signal and the detection signal are sent to the determination circuit 3 by the EEPROM. Processing to be stored in the set value storage circuit 7 is executed.
The registration switch performs four predetermined operations (detection signal zero value registration operation, detection signal span value registration) for storing the zero value and span value for the setting signal and the detection signal in the EEPROM setting value storage circuit 7. Operation, setting signal zero value registration operation, setting signal span value registration operation) is possible, and according to each predetermined operation, four predetermined registration commands (detection signal zero value) are sent to the judgment circuit 3. Registration command, detection signal span value registration command, setting signal zero value registration command, setting signal span value registration command). In accordance with these signals, the determination circuit 3 causes the EEPROM setting value storage circuit 7 to store the zero value and the span value for the setting signal and the detection signal.

The valve positioner A further includes a changeover switch circuit 12, a path changeover circuit 13, and a multicolor display circuit 14.
The changeover switch circuit 12 is connected to an operation switch (not shown), and outputs a predetermined control stop signal to the motor drive circuit 8 when a predetermined control stop operation is performed on the operation switch. . Further, when a predetermined input switching operation is performed on the operation switch, a predetermined input switching signal is output to a path switching circuit 13 described later.
The motor drive circuit 8 switches between an operating state in which the motor 4 is controlled and a resting state in which the motor 4 is not controlled according to the presence or absence of the control stop signal.
Whether the path switching circuit 13 uses a signal input to the A / D converter 2a through the setting value input circuit 1 as the setting signal input from an external device in the signal standard (predetermined signal form). Whether to use the output detection signal output from the opening output circuit 10 is switched. This switching is performed according to the presence or absence of the input switching signal from the selector switch circuit 12. When the input switching signal is not present (OFF), the setting signal is input (transmitted) to the A / D converter 2a. When the input switching signal is present (ON), the output detection signal (an example of the adjusted signal) whose output is adjusted by the opening output circuit 10 is input to the A / D converter 2a. The set value input circuit 1 and the path switching circuit 13 are examples of signal switching means. Hereinafter, a path from the set value input circuit 1 to the determination circuit 3 is referred to as a signal input path (an example of one signal transmission path).
More specifically, the path switching circuit 13 outputs the output signal (adjusted signal) of the opening output circuit 10 to the set value input circuit 1 in accordance with the switching signal from the selector switch circuit 12. Switch between no.
Thus, in the state where the output detection signal (an example of the adjusted signal) whose signal level is adjusted by the opening degree output circuit 10 is input to the set value input circuit 1 through the path switching circuit 13. When the external input terminal of the set value input circuit 1 is opened, the output detection signal is sent to the determination circuit 3 (set signal zero span setting means) via the signal input path (an example of one signal transmission path). It is input in some examples).
On the other hand, when an external device is connected to the external input terminal of the set value input circuit 1 in a state where the output of the output detection signal to the set value input circuit 1 is blocked by the path switching circuit 13, the set signal Is input to the determination circuit 3 (an example of valve control means) via the signal input path (an example of one signal transmission path).
The multicolor display circuit 14 displays information related to a determination result (described later) by the determination circuit 3 on a display unit including LEDs and the like whose lighting color can be switched. Here, as the LED, an LED whose emission color can be switched to any one of three colors of red, blue, and yellow is used.

The control operation of the motor 4 in the valve positioner A is the same as the operation of the valve positioner B in the conventional example as follows.
That is, when a setting signal corresponding to the set angle (target angle) of the valve is input to the set value input circuit 1 from an external device such as an angle setting device (not shown), the set signal is converted into an A / D converter. It is converted into a digital signal by 2a and input to the decision circuit 3.
On the other hand, the operating angle feedback signal generator 5 connected to the output shaft of the motor 4 detects the current operating angle of the valve, and the detection signal of the signal level corresponding to the operating angle is sent through the feedback input circuit 6. The signal is input to the A / D converter 2b, digitized, and input to the determination circuit 3.
Then, the determination circuit 3 converts the detection signal and the setting signal, respectively, based on the zero value and the span value stored in the EEPROM setting value storage circuit 7, and the conversion results respectively. The drive torque of the motor 4 is controlled (that is, the drive power is controlled) so as to reduce the difference.
As described above, the determination circuit 3 (an example of the valve control unit) converts the setting signal with the zero value and the span value (an example of setting information by the setting signal zero span setting unit) and the detection signal. The motor 4 is controlled on the basis of the zero value and the result converted into the span value, and the operating angle of the valve is controlled.

FIG. 2 is a flowchart showing a procedure of zero span setting in the valve positioner A according to the embodiment of the present invention.
The procedure for setting the zero span of the setting signal, setting the zero span of the detection signal, and setting the zero span of the detection signal for output in the valve positioner A will be described below with reference to FIG.
In the following, the signal standards of the setting signal and the output detection signal are 4 mA to 20 mA, the fully closed position of the operating angle of the valve is associated with the minimum level of 4 mA of the setting signal, and the valve is fully closed. The zero span setting for associating the range from the position to the fully open position with the setting signal span (16 mA) will be described. S201, S202,... Represent procedure (step) numbers. In the initial state of the following procedure, external devices are not connected to the input terminal of the set value input circuit 1 and the output terminal of the opening output circuit 10 (that is, in the released state). And
First, when the control stop operation is performed on the operation switch connected to the changeover switch circuit 12, the motor drive circuit 8 enters a halt state according to the control stop signal output from the changeover switch circuit 12 ( S201).
Next, the user fully closes the operating angle of the valve manually (S202). As a result, the detection signal at the minimum level corresponding to the fully closed state is output by the operating angle feedback signal generator 5, and the signal value (digital value) of the detection signal at the minimum level is input to the determination circuit 3. In addition, the output detection signal whose signal value is converted into an analog signal is input to the opening degree output circuit 10.
In this state, when a predetermined detection signal zero value registration operation is performed on the registration switch, a detection signal zero value registration command is output from the registration switch circuit 11 to the determination circuit 3, and the minimum level detection signal is output. Is stored in the EEPROM set value storage circuit 7 as a zero value of the detection signal for the full closing of the valve (S203).
In this state, a current measuring device is connected to the output terminal of the opening degree output circuit 10 (S204). Then, the zero value adjustment knob is operated and adjusted so that the detection value by the current measuring device becomes the minimum level (4 mA) in the signal standard (4 to 20 mA) of the output detection signal (S205). Hereinafter, the output detection signal whose signal level is adjusted to 4 mA is referred to as an output reference detection signal.

  When the zero value setting of the output detection signal is completed, the user removes the current measuring instrument connected to the opening output circuit 10 (S206). When the user performs a predetermined input switching operation on the operation switch connected to the changeover switch circuit 12, the input changeover signal is output (ON) from the changeover switch circuit 12 to the path changeover circuit 13. (S207). As a result, an output signal (the output reference detection signal) whose signal level is adjusted by the opening degree output circuit 10 is sent to the A / D converter 2a via the path switching circuit 13 and the set value input circuit 1. , Converted to a reference signal value (digital value) corresponding to the signal level, and input to the determination circuit 3. In this state, when a predetermined setting signal zero value registration operation is performed on the registration switch, a setting signal zero value registration command is output from the registration switch circuit 11 to the determination circuit 3, and the reference signal value (digital value) is , And stored in the EEPROM set value storage circuit 7 as a zero value corresponding to the fully closed state of the valve (S208).

Here, when the user again performs the input switching operation on the operation switch, the output of the input switching signal is stopped (OFF) by the changeover switch circuit 12 (S209). As a result, the output detection signal is output from the external output terminal of the opening degree output circuit 10.
Next, the user manually sets the operating angle of the valve to full open (S210). As a result, the detection signal of the maximum level is output by the operating angle feedback signal generator 5, and the signal value (digital value) of the detection signal of the maximum level is input to the determination circuit 3, and further the signal value The output detection signal converted into an analog signal is input to the opening degree output circuit 10.
In this state, when a predetermined detection signal span value registration operation is performed on the registration switch, a detection signal span value registration command is output from the registration switch circuit 11 to the determination circuit 3. A difference obtained by subtracting the reference detection signal value from the maximum signal value is calculated, and the difference is stored as a span value in the EEPROM setting value storage circuit 7 (S211).
In this state, the user connects a current measuring device to the output terminal of the opening degree output circuit 10 (S212), and the detected value by the current measuring device is the signal standard (4 to 20 mA) of the output detection signal. The span value adjusting knob is operated and adjusted so that the maximum level (20 mA) is reached (S213). Hereinafter, the output detection signal whose signal level is adjusted to 20 mA is referred to as an output maximum detection signal.

When the span value setting of the output detection signal is completed, the user removes the current measuring instrument connected to the opening output circuit 10 (S214). Here, when the user performs a predetermined input switching operation on the operation switch, the input switching signal is output (ON) from the switching switch circuit 12 to the path switching circuit 13 (S215). Thereby, the output signal (the maximum detection signal for output) whose signal level is adjusted by the opening degree output circuit 10 is sent to the A / D converter 2a via the path switching circuit 13 and the set value input circuit 1. The signal is input, converted to a maximum signal value (digital value) corresponding to the signal level, and input to the determination circuit 3. When a setting signal span value registration operation is performed on the registration switch in this state, a setting signal span value registration command is output from the registration switch circuit 11 to the determination circuit 3, and the reference value span (digital value) is used as the reference. A difference value obtained by subtracting the signal value (zero value) is calculated, and the difference value is stored as a span value in the EEPROM set value storage circuit 7 (S216).
Thus, the registration switch circuit 11 and the determination circuit 3 (an example of setting signal zero span setting means), the signal level is set to the minimum level of the signal standard (4 to 20 mA) of the setting signal by the opening output circuit 10. Based on the output detection signal (adjusted signal) adjusted to (4 mA) or the maximum level (20 mA), the zero value and span value (information on the zero value and span value span value) of the previous period setting signal are set. The Therefore, the signal generator required in the conventional example is not necessary. Similarly, the registration switch circuit 11 and the determination circuit 3 (an example of detection signal zero span setting means) make the zero value and span value of the detection signal based on the detection signal (information on the zero value and span value span value). Is set.

By the way, when the zero span setting is performed according to the procedure shown in FIG. 2, the zero value and the span value of the setting signal and the detection signal are slightly varied depending on the characteristics of the apparatus and the installation state of the device. Usually it falls within a predictable default range. However, for example, when the zero span setting is performed without correctly performing the step S101 of fully closing the valve angle or the step S105 of fully opening the valve angle, the zero of the setting signal and the detection signal is set. The value and the span value deviate from the predetermined range, and an erroneous zero span setting can be made.
Therefore, in the positioner A, the zero value and the span value to be stored in the EEPROM setting value storage circuit 7 are within predetermined setting ranges (predetermined ranges) as shown below. Whether or not (exceeded or not) information is output.
That is, the determination circuit 3 includes a storage unit (not shown) that stores the setting ranges (predetermined ranges) of the zero value and the span value for each of the detection signal and the setting signal.
When the determination circuit 3 inputs a zero value or span value registration command from the registration switch circuit 11 in each of the aforementioned steps S203, S208, S211 and S216 (see FIG. 2), the detection signal at that time is input. Or whether the value (digital value) of the setting signal (actually, the output detection signal input instead) is within the setting range corresponding to the zero value or span value of each signal value. Determine.

Further, the determination result is displayed on the display unit composed of LEDs or the like by the multicolor display circuit 14. That is, the multicolor display circuit 14 and the LED (an example of detection signal zero span information output means and setting signal zero span information output means) are stored in the EEPROM set value storage circuit 7 in response to a command from the registration switch circuit 11. Information indicating whether the zero value and the span value of the setting signal and the detection signal exceed the setting range (predetermined range) (an example of output).
For example, an LED that can switch the emission color to one of three colors of red, blue, and yellow is used. If the signal value is within the set range, the signal is blue, and if the signal value is below the set range, the signal is yellow. If the value exceeds the set range, red light is emitted. In addition, it is conceivable to output the discrimination result in a blinking state of a light emitting means such as an LED (flashing when exceeding the range, etc.), an alarm sound, or the like.
As a result, the user can easily recognize that the abnormal zero span setting is being performed, so that the abnormal zero span setting can be prevented beforehand by re-setting or the like.

In the above-described embodiment, an example in which the output switching signal after signal level adjustment is input to the determination circuit 3 using the path switching circuit 13 is disclosed, but the configuration of the present invention is limited to this. is not. For example, in FIG. 1, a configuration in which a second path for connecting the opening output circuit 10 to the determination circuit 3 is provided and a new A / D converter is provided on the second path is also an example of the present invention. Can be considered as.
In this configuration, the output detection signal is input from the second path, and the setting signal is input from the path provided with the A / D converter 2a. Therefore, if the determination circuit 3 determines in advance that the digital signal input via the second path is used for the zero span setting of the setting signal, the open circuit is the same as in the embodiment of the present invention. The output detection signal whose signal level is adjusted by the output circuit 10 can be used for zero span setting.

Similarly, a configuration in which a zero span circuit or the like for the purpose of processing for zero span setting is provided separately from the determination circuit 3 is also considered as an example. In this configuration, the digital signal from the A / D converter 2b has two output destinations: the determination circuit 3 and the zero span circuit. The output terminal of the opening output circuit 10 is also connected to the zero span circuit.
In this case, the detection signal from the A / D converter 2b is input to the zero span circuit, and the output detection signal whose signal level is adjusted is input from the opening output circuit 10. Therefore, if the zero span setting of the setting signal and the detection signal is performed by the zero span circuit, the output detection in which the signal level is adjusted by the opening output circuit 10 as in the embodiment of the present invention. The signal can be used for zero span setting.

In an embodiment of the present invention, a minimum signal level (zero value) in the signal standard (4 to 20 mA) of the setting signal and the output detection signal is set to a fully closed operating angle of the valve, and a signal level range of 16 mA. The zero span setting that corresponds to the range of operating angle from fully closed to fully open has been explained. Of the predetermined signal levels (4 mA to 20 mA), 4 mA (zero value) is fully closed to the valve operating angle. In addition, a zero span setting may be performed so that 20 mA corresponds to the fully closed operation angle of the valve.
When the fully closed operating angle is 0 ° and the fully opened operating angle is 90 °, when the valve operating angle is controlled in the range of 0 ° to 45 °, the fully closed and 4 mA signal level ( It is conceivable to correspond to a signal level range of 16 mA (span value) and an operating angle range of 0 ° to 45 °.

The block diagram showing the schematic structure of the valve drive device X provided with the valve positioner A which concerns on embodiment of this invention. The flowchart which shows the procedure of the zero span setting in the valve positioner A which concerns on embodiment of this invention. The block diagram showing schematic structure of the valve drive device Y provided with the valve positioner B which concerns on a prior art example. The flowchart which shows the procedure of the zero span setting in the valve positioner B which concerns on a prior art example.

Explanation of symbols

A: Valve positioner B according to an embodiment of the present invention ... Valve positioner X according to the prior art ... Valve drive device Y provided with valve positioner A ... Valve drive device 1 provided with valve positioner B ... Set value input circuit 2a, 2b ... A / D converter 3 ... judgment circuit 4 ... motor 5 ... operating angle feedback signal generator 6 ... feedback input circuit 7 ... EEPROM set value storage circuit 8 ... motor drive circuit 9 ... D / A converter 10 ... opening Output circuit 11 ... Registration switch circuit 12 ... Changeover switch circuit 13 ... Path switching circuit 14 ... Multicolor display circuit

Claims (5)

Detection signal adjusting means for adjusting the detection signal of the valve operating angle to a predetermined signal form;
A setting signal zero span setting means for setting information on the zero value and the span value of the valve operating angle setting signal inputted from the outside in the predetermined signal form based on the adjusted signal after adjustment by the detection signal adjusting means; ,
Valve control means for controlling a valve operating angle using a result obtained by converting the setting signal based on setting information by the setting signal zero span setting means;
A valve positioner comprising: Comprising a signal switching means for switching either the adjusted signal or the setting signal to be transmitted to one signal transmission path;
2. The setting signal zero span setting means inputs the adjusted signal through the one signal transmission path, and the valve control means inputs the setting signal through the one signal transmission path. The described valve positioner. Detection signal zero span setting means for setting information on a zero value and a span value of the detection signal based on the detection signal;
Detection signal zero span information output means for outputting information as to whether or not one or both of the zero value and span value of the detection signal to be set by the detection signal zero span setting means exceeds a predetermined range; The valve positioner according to claim 1 or 2.   A setting signal zero span information output means for outputting information on whether or not one or both of the zero value and the span value of the setting signal to be set by the setting signal zero span setting means exceeds a predetermined range. Item 4. The valve positioner according to any one of Items 1 to 3.   A valve driving device comprising: an actuator for driving a valve; and the valve positioner according to claim 1 for controlling driving of the actuator.

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