JP3075324B2 - Servo type recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo type recorder,
More specifically, the present invention relates to control of response characteristics of a recording pen.

[0002]

2. Description of the Related Art Servo recorders configured to record the magnitude of a measurement signal on recording paper by moving a recording pen in accordance with the magnitude of a measurement signal by a servo system are widely used in various fields. Have been. By the way, in such a servo type recorder, if the recording pen is set to respond at high speed to the change of the measurement signal, if the measurement signal greatly changes from a full scale value to zero, for example, the recording is performed. The pen converges to the zero position while vibrating around the zero position which is the target value. As a result of the vibration of the recording pen, a vibration waveform is recorded on the recording paper even though the measurement signal itself does not vibrate.

To solve such inconveniences, for example, a filter is provided in the input section, mechanical elements constituting the servo system are changed, or the response characteristics of the recording pen are changed by software processing. ing.

[0004]

However, when a filter is provided in the input section, the measurement signal itself is subjected to a filtering process, and the setting and monitoring functions of an alarm performed based on the measurement signal are also performed. Will have an effect. Further, when changing the mechanical elements constituting the servo system, there is a problem that the number of components for the change increases and the cost increases. Since the change is made by switching the constant, the changeable range is limited to some extent.

Further, when the response characteristics of the recording pen are changed by software processing, high-speed response cannot be obtained. SUMMARY OF THE INVENTION The present invention solves such a conventional problem, and an object of the present invention is to realize a servo-type recorder that can arbitrarily set a response characteristic of a recording pen without affecting a measurement signal. is there.

[0006]

The servo type recorder according to the present invention is configured such that a recording pen is moved by a servo system according to the magnitude of a measurement signal to record the magnitude of the measurement signal on recording paper. An A / D converter for converting an analog measurement signal into a digital signal,
An arithmetic processing unit for performing arithmetic processing for converting a digital signal converted and output from the D converter into a physical quantity, and a filter for giving a desired time constant to the digital signal output from the arithmetic processing unit A filter operation unit for performing an operation and a D / A converter for converting an output of the filter operation unit into an analog signal and inputting the analog signal to a servo system are provided.

[0007]

The signal relating to the measurement signal input to the servo system is subjected to a filter operation for giving a desired time constant immediately before the signal is input to the servo system. By appropriately selecting the time constant given to the signal related to the measurement signal in accordance with the magnitude of the change amount, it is possible to prevent overshoot due to the movement of the recording pen and to respond to the state of change of the measurement signal. Stable recording is obtained.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a main part showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a CPU, which controls the operation of each unit of the entire apparatus and performs arithmetic processing for converting a digital signal converted and output from the A / D converter 3 into a physical quantity. Reference numeral 2 denotes a measurement signal input terminal, which is connected to the A / D converter 3. A ROM 4 stores fixed data such as programs. A RAM 5 stores variable data such as measurement conditions and measurement data.
Reference numeral 6 denotes a recording sheet which is fed at a predetermined speed arbitrarily set by a motor 7. Reference numeral 8 denotes an amplifier for driving the motor 7. Reference numeral 9 denotes a recording pen, which is driven to be displaced by a servo system including a servomotor 10 in accordance with the magnitude of a measurement signal. Reference numeral 11 denotes an amplifier for driving the servo motor 10, and reference numeral 12 denotes a servo amplifier. An output signal of a feedback operation block 13 for generating a signal for feeding back the current position of the recording pen 9 is input to one input terminal of the servo amplifier 12, and an output of the D / A converter 14 is input to the other input terminal. Signal is input. The output signal of the variable filter block 15 is input to the input terminal of the D / A converter 14. The A / D converters 3 and R
The OM 4, the RAM 5, the amplifier 8, and the variable filter block 15 are connected to the CPU 1 via the bus 16.

In such a configuration, the variable filter block 15 functions as a low-pass filter, and the filter characteristics of the variable filter block 15 correspond to an external contact input signal (not shown) related to an external event or the magnitude of a measurement signal to be recorded (recording position). For example, it is configured as a digital filter so that it can be appropriately changed according to the above. Since the variable filter block 15 is connected to a stage preceding the D / A converter 14 which is input to one input terminal of the servo amplifier 12 constituting the servo system, the servo system may change the state of the measurement signal if necessary. Can be given an appropriate filter characteristic.

According to such a configuration, the CPU
Since the filtering process is performed on the physical quantity conversion signal related to the measurement signal that has been subjected to the arithmetic processing in step 1, there is no adverse effect due to the filtering process on the alarm function and the monitoring function. FIG. 2 shows the variable filter block 15.
5 is a flowchart showing a flow of the operation of FIG. In the following description, X = servo output value Y = previous servo output value α = filter constant.

First, it is determined whether or not to perform a filtering process (step). If it is determined that the filter processing is to be performed, a filter calculation processing of Y = α · Y + (1−α) · X is executed (step), and the result Y calculated in this step is output to the servo system (step). . On the other hand, if it is determined that the filter processing is not to be performed, the filter calculation processing of Y = X is executed (step), and the result Y calculated in this step is output to the servo system (step).

A specific example will be described. As described above, in the servo system having a fast response, when the amount of change of the measurement signal is large and the amount of movement of the recording pen 9 is large, the moving speed of the recording pen 9 also increases, so that the recording system reaches the target position and stops. Overshoot occurs by then. In preventing such an overshoot, the magnitude of the change amount of the measurement signal is monitored, and only when the change amount is larger than a certain value, a certain time or until the change amount decreases to a certain value. During this time, the filter processing may be performed.
For example, when the operation of turning off the measurement signal is performed, the recording pen 9 should theoretically record 0. However, in the servo system having a fast response, the recording pen 9 swings to the minus side due to overshoot, and the recording pen 9 may not record. May be recorded on recording paper. Looking at only the recording result, it cannot be determined whether the recording result is due to such an overshoot or represents a change in the measurement signal itself. Therefore, CPU1
To detect the recording off and turn on the variable filter block 15. Thus, the occurrence of overshoot of the recording pen 9 can be prevented, and the recording pen 9 can perform recording without overshoot.

Further, for example, when the measurement signal shows a non-linear characteristic of logarithmic input as shown in FIG. 3, a stable recording result can be obtained by changing the filter coefficient according to the magnitude (recording position) of the measurement signal. In the case of FIG. 3, the change of the recording position with respect to the change of the input signal increases as the recording position approaches the 0% side. Therefore, in order to perform a stable recording operation, the filter coefficient is changed at, for example, a recording position of 50%, so that the time constant is increased below 50%, and the time constant is decreased above 50%. Adjust the filter coefficient to. Thereby, the response of the movement of the recording pen 9 to the change of the measurement signal at the recording position near 0% becomes low, and a stable recording operation can be obtained.

[0014]

As described above, according to the present invention,
A servo type recorder capable of arbitrarily setting the response characteristics of the recording pen without affecting the measurement signal can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a flow of the operation in FIG. 1;

FIG. 3 is a diagram illustrating a specific example of a measurement signal.

[Explanation of symbols]

 1 CPU 2 Input terminal 3 A / D converter 4 ROM 5 RAM 6 Recording paper 7 Motor 8 Motor drive amplifier 9 Recording pen 10 Servo motor 11 Motor drive amplifier 12 Servo amplifier 13 Feedback calculation block 14 D / A converter 15 Variable filter Block 16 bus

Claims (1)

(57) [Claims] 1. A servo type recorder configured to move a recording pen according to the magnitude of a measurement signal by a servo system and record the magnitude of the measurement signal on recording paper. An A / D converter for converting the digital signal into a digital signal; an arithmetic processing unit for performing arithmetic processing for converting a digital signal converted and output from the A / D converter into a physical quantity; and a digital signal output from the arithmetic processing unit. A filter operation unit for performing a filter operation for giving a desired time constant to a signal; and a D / A converter for converting an output of the filter operation unit into an analog signal and inputting the analog signal to a servo system. Features a servo type recorder.