Shimadzu Corporation

Hajime Bungo

Yugo Ishihara

An analytical device including a main circuit, a main power supply switch and a control unit which acquires measurement data from main circuit and exchanges data with another device. Said analytical device further includes a hard switch and a relay switch which assumes either an ON state in which electric power is supplied to the main circuit or an OFF state in which electric power is not supplied to the main circuit, wherein the control unit, upon receiving input of a first input signal for setting the main power supply switch to an OFF state, if the main circuit is causing the device main body unit to operate, provides notification of the fact that the device main body unit is operating, and upon receiving input of a second input signal for setting the main power supply switch to an OFF state, sets the relay switch to an OFF state.

Analytical device

Provided is a spectrophotometer having a sample container, a light-source unitfor casting measurement light into the sample container, a photodetectorfor detecting light obtained from the sample containerilluminated with the measurement light, a light separatorplaced between the light-source unitand the sample container, an A/D converterfor converting detection signals from the photodetectorinto digital signals, and an A/D conversion time controllerfor controlling an A/D conversion time in the A/D converter. The A/D converterreceives, for each A/D conversion time, detection signals sequentially produced by the photodetector, and sequentially outputs values corresponding to the amounts of signals received. The A/D conversion time controllercontrols the A/D conversion time at five times (preferably, ten times) the cycle of commercial power supplies or longer during wavelength-correctness validation of the light separator

Spectrophotometer

Provided is a deuterium lamp power supply circuit capable of preventing the application of a high switch-to-ground voltage to a switch when applying a voltage between a positive electrode and negative electrode to light a deuterium lamp. The power supply circuit includes a capacitor for applying a voltage between the positive electrode and the negative electrode, with one terminal of the capacitor being connected to the positive electrode; a power supply, installed between the capacitor and the negative electrode, for charging the capacitor; and a two-terminal switch connected in parallel to the power supply. The switch is placed at a location close to ground, and thus a high switch-to-ground voltage is not applied to the switch.

Deuterium lamp power supply circuit

A constant-current power source unit has a variable power source which can adjust an output voltage. To detect a voltage applied to the gas discharge tube, a voltage detection unit is provided. A power source controlling unit configured to control the voltage by adding a predetermined voltage to the voltage taken in from the voltage detection unit after the electric discharge is started in the gas discharge tube.

Light source apparatus

The present invention provides a detector for a chromatograph capable of obtaining the accurate retention time, even if there is a frequency deviation of the clock signal for determining the timing of data sampling, by conforming the progress of the detector internal time accompanied with the repetition of the sampling to that of real time. In the detector, consecutive data sampling intervals are defined to be a time adjustment period, and in one time adjustment period, each of the sampling intervals whose number is given as the interpolation value M is elongated by a predetermined number of clock counts compared to each of the other sampling intervals. If the clock signal has a positive frequency deviation, the apparatus internal time determined by the clock signal progresses faster than real time. However, providing the interpolation value M corresponding to the amount of the frequency deviation elongates the time adjustment period on the basis of the apparatus internal time, to be conformed to the time adjustment period on the basis of real time which is determined by the sampling period.

Method for adjusting the detector of a chromatograph

When the apparatus is energized or a validation check is performed, a deuterium lampis turned on, and an output value resulting from an A/D conversion of the detection signal for light with a wavelength of 235 nm is obtained. A data processorcompares the output value with an upper limit value, which was determined and stored beforehand in a memory(normally, in the manufacturing stage of the apparatus). If the output value is not less than the upper limit, a controlleroperates an aperture driverto reduce the light quantity by means of an adjustable aperture. This operation prevents an excessive quantity of light from reaching a photodetector, so that the measurement without absorption by a sample solutioncan be correctly performed, and the absorbance by the sample solutioncan be correctly calculated.

In a spectrophotometer, a position of a motor corresponding to a 254 nm bright line in the last check is read out from a memory section, and only a low-pressure mercury lamp is lighted up to scan a grating around the 254 nm line position in the last check, so that the 254 nm line position where a 254 nm line is ejected on a cell is detected. The low-pressure mercury lamp is turned off, and after only a D lamp is lighted up, the grating is scanned to detect an original position where an original or zero-order light is ejected on the cell and a 656 nm line position where a 656 nm line is ejected on the cell. Then, based on the 254 nm line position and the 656 nm line position which are actually measured, wavelength check is carried out.

A detection device for an apparatus for carrying out analysis such as a chromatograph includes not only a detector for outputting detection signals but also a stabilization judging unit for measuring drift and noise of these detection signals over time and automatically transmitting a start signal which permits the apparatus for analysis to start its operations when the measured drift becomes smaller than a standard drift value such as one-tenth of the optical absorbance measured for a spectrum of an analyzed sample at the detection wavelength. A standard noise value setting unit may be further provided for receiving detection signals at detection wavelength while a standard sample is placed inside a detection cell, calculating a standard noise value on the basis of intensity of the detection signals, and transmitting the calculated standard noise value to the stabilization judging unit. A standard drift value setting unit may also be further provided in the case of a chromatograph with a column for storing standard drift values corresponding to measured temperature of the column when measurements are taken by the chromatograph and transmitting the retrieved drift value to the stabilization judging unit.

Detection device for apparatus for analysis

A multi-channel type spectro-photometer not only has a light source, a sample cell to which light from the light source is directed, a spectrometer to which light transmitting through the sample cell is directed, and an array of photo-diodes to which dispersed light from the spectrometer is directed, but also allows the user to specify a range of wavelength within which measurements are to be taken. An optimum charge-accumulating time during which charge is to be accumulated on the photo-diodes array is automatically set according to the range specified by the user. Alternatively, quantity of light received by the photo-diode array may be detected and an optimum charge-accumulating time may be automatically set according to the measured light intensity on the photo-diode array. Dark current and background measurements are taken before a sample is injected into the sample cell and transmitted light therethrough is measured to obtain the absorption spectrum of the sample.

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Muko, Japan

Hajime Bungo