JPS6385404A - Amplifying device - Google Patents

Abstract

PURPOSE:To read a measured value on the best scale by setting amplification values in a programmable gain amplifier and a multiplication type D/A converter with a full-scale value which is inputted and indicated corresponding to the rated value of a detector. CONSTITUTION:The preamplifier of an amplifying device 20 which amplifies a signal outputted by the detector 1 is composed of a programmable gain measuring amplifier 9, and the multiplication type D/A converter 8 is installed between the amplifier 9 and a postamplifier 7. Then a desired full-scale value is inputted on a keyboard 18 corresponding to the rated value of a measuring instrument 1 and then an arithmetic means 11 calculates and sets the amplification values of the converter 8 and amplifier 9 so that the full scale at the time of the maximum gain coincides with the desired full-scale value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an amplification device used for amplifying an electrical signal output from a detector or the like.

[Prior Art] When amplifying a detection signal from a detector, an amplification device as shown in FIG. 4, for example, is generally used. This figure shows the configuration of a detection amplification device used in a strain gauge type sensor. The excitation amplifier 3 of the amplifier device 2 outputs an excitation signal eXo to the detector 1 based on the reference signal eX. The detected signal ±e8 from the detector 1 is input to the front-stage amplifier 5 of the amplifier 2, and is output from the rear-stage amplifier 7 as a signal amplified by these amplifiers. A magnification setting section 6 is provided between the front-stage amplifier 5 and the rear-stage amplifier 7, and the magnification setting section 6 sets a magnification for the detection signal.

[Problems to be Solved by the Invention] However, the magnification setting section of the conventional amplifier described above is configured as a variable range; X5. XI
Because of the fixed range of the O series, if you want to record a signal that scales over at a certain magnification, you have to change the range by one step and use a value such as % of the range full scale. There was a problem in that it was not possible to obtain monitor output. Furthermore, it was not possible to set the full scale value at any magnification.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an amplification bag device in which the range ratio can be made stepless and the degree of amplification can be arbitrarily set.

[Means for Solving the Problems] In order to solve the above problems, the present invention employs the following configuration.

That is, the amplification device according to the present invention is an amplification device that amplifies a signal output from a detector or the like, and includes a programmable gain measurement amplifier provided in a previous stage to which the signal is input, and a programmable gain measurement amplifier provided in series with the programmable gain measurement amplifier. a multiplication type D/A converter, an input means for inputting a desired full scale value for the rated value of the detector, etc., and a multiplication type D/A converter and a multiplication type D The present invention is characterized in that it includes a full-scale value setting means comprising calculation control means for calculating an amplification value to be set in the /A converter and setting the calculated amplification value thereto.

[Function] When a full scale value is input from the input means, the arithmetic control means calculates the amplification values to be set in the programmable gain measurement amplifier and the multiplication type D/A converter, respectively.
The amplification values are set in a programmable gain measurement amplifier and a multiplication type D/A converter, respectively. When setting the amplification level for the programmable gain measurement amplifier, the amplification level can be set widely, and for the multiplication type D/A converter, the amplification level can be set arbitrarily within the resolution range, so the detector etc. The full scale value can be set arbitrarily for the rating.

[Example] Fig. 1 is a block diagram showing the configuration when an amplifier according to an embodiment of the present invention is applied as a detection amplifier of a strain gauge type detector of a material testing machine. Show the same thing.

The amplifier device 20 according to the present invention replaces the pre-stage amplifier 5 in the conventional amplifier device with a programmable gain measurement amplifier 9, installs a multiplication type D/A converter 8 between the amplifier 9 and the post-stage amplifier 7, and has a CPU I+ , parallel input/output device 11,
12, R2M17. RAM]6. keyboard 18
It is configured to set the amplification value calculated by the control section consisting of the programmable gain measurement amplifier 9 and the multiplication type D/A converter 8.

The amplification values calculated by the control section and set in the multiplication type D/A converter 8 and the programmable gain measurement amplifier 9 will be explained. For example, the rating of detector 1 is ]00 tons, the sensitivity e
8 is Imv/lon, and the range for the gain Xp of the programmable gain measurement amplifier 9 in the previous stage is X10.
X 20. X 50. X 100. X 200. X
500° x 1000, and the gain X of the rear stage amplifier 7 is set to 10 times. The rated output voltage is ]Ov/FS. If the multiplication type D/A converter is 12 bits, the resolution is ]/
4096, and the maximum gain Xd is 40957
At 4096, the minimum gain is zero.

If the values of each part are set in this way, the range full scale at the minimum gain is Iton, and the output e0 for the detection signal e5 from the detector 1 is eo = e, XXp X
At X, 1 xXr-(+), x ]0=9.9976V. The error is small for the rated output voltage value of 10V.

In equation (1), xd is expressed as: In equation (2), X is the full scale value at the maximum gain as FM, the desired full scale value Fs, and the set gain xP of the programmable gain measurement amplifier 9. )
It is expressed as X 4096- (3).

Therefore, we set an arbitrary full scale value to, for example, 80 ton/F.
If you input from the keyboard 18 as s, the CPU 11
first determines xp. Now if Xp=20, then X is X = (]780) X (1000/20) X
4096=2560. The c p U 10 once sets the calculated amplification values XP-20 and X=2560 in the parallel input/output device 12.13, and inputs them to the multiplication type D/A converter 8 and the programmable gain measurement amplifier 9. The gain Xd of the D/A converter 8 is X d = 2560
/4096 = 0.625.

80ton/F, the detection signal e5 from the detector 1 is ell=Imv/1. on x 80t
on=80 mv. Therefore, the output e at a scaling of 80 ton/F. From equation (1), e. = 80
mvX 20X O, 625X ]0=10v, and the error is 0% with respect to the rated output value. In this way, the multiplication type D/A converter 8 and the programmable gain instrumentation amplifier 9 are controlled so that for any full scale value instructed from the keyboard 18, the CPU 11 obtains the same output as the full scale at the maximum gain. Since the amplification value is calculated and set to this value, any value can be set as the full scale.

FIGS. 2 and 3 are flowcharts showing the processing procedure in the CPU II. First, if the RAM 16 is backed up by the battery 17, its contents are checked. RAM] 6, input the rated value of the detector 1, and then input the setting value X of the programmable gain measurement amplifier 9 and the multiplication type D.
/Write the default value of the amplification value Xd of the A converter 8.

Next, the set value xp and the amplified value Xd are read from the RAM 16 and set in the parallel input/output devices 12 and 13, respectively.

Determine whether or not there is a scaling change instruction, and if there is a change, input the full scale value FS, determine Xp for Fs, and calculate the full scale value FM and full scale value F at maximum gain.
Find the value of xd from s and Xp, and use the values of Xp and Xd as RA
M 16, this value is set to the parallel input/output device 12.13, and a new amplification value xp
and Xd are programmable gain measurement amplifier 9 and multiplication type D
/A converter 8. Details of the process 20 in the flowchart of FIG. 2 are shown in the flowchart of FIG. 3. That is, it is determined whether or not the full scale value Fs instructed to be set via the keyboard 18 exceeds the detection range of the detector, and if it does, error processing is performed as an input error. If it is within the detection range, the xp range changes to XIO, X20, etc. according to the full scale setting instruction.
As well as being determined as X500 and X1000,
If the FM calculation formula is determined and the detector is at the rated value, then X =
4095, otherwise X = 4096X
(FM/Fs), and Xd is obtained.

2, any value can be read as the range full scale simply by specifying the full scale value from the keyboard 18, so there is no need to select a range in consideration of the range ratio as in the past. Additionally, any value can be measured as a full scale, making it easier to match it with a recorder. The motor output can always be used at its maximum, improving the signal-to-noise ratio and improving measurement accuracy.

In the above embodiment, the gain of the multiplication type D/A converter is set to 1 or less, but by setting the gain to 1 or more, the burden on the subsequent stage amplifier can be reduced or eliminated. In addition, when matching the detector and the detection amplifier of the amplifier, it is possible to incorporate several errors due to overall nonlinearity, calculate the correction function in advance on the CPU, and use this correction function when calculating the amplification value. Comprehensive error correction including the detector is also possible.

[Effects of the Invention] As is clear from the above description, the amplifier according to the present invention can set the range of the amplifier in stages to set an arbitrary amplification value, and can read the measured value on the most appropriate scale with the recorder. Now you can.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration when an amplifier according to an embodiment of the present invention is applied as a detection amplifier of a strain gauge type detector of a material testing machine, and FIGS. 2 and 3 are C
A flowchart showing the processing procedure in the PU, and FIG. 4 is a block diagram showing the configuration of a conventional example. 1...Detector 7...Late stage amplifier 8...
Multiplying D/A converter 9...Programmable gain measurement amplifier 11...C
P U 12, 13...Parallel input/output device 15
...ROM 16-...RAM patent applicant Shimadzu Corporation Agent Patent attorney Hiroshi Sugawara Figure 1

Claims (1)

[Claims] (1) An amplifier device that amplifies the signal output from a detector, etc., which includes a programmable gain measurement amplifier, a multiplication type D/A converter installed in series with the programmable gain measurement amplifier, and the ratings of the detector, etc. an input means for inputting a desired full-scale value for the value; and an amplification value to be set in the programmable gain measurement amplifier and the multiplication type D/A converter in accordance with the instructions from the input means. 1. An amplification device comprising: full scale value setting means; and arithmetic control means for setting amplification values.