JPH0567914B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for generating a sweep step signal when outputting an analog sweep signal in a computer-assisted measurement system.

[Prior Art] Conventionally, it has been possible to apply a voltage or current to an object under test composed of an analog circuit, measure the output at that time, and judge whether the object under test is good or bad from the measured output. There is a computer-aided testing device.

As shown in FIG. 5, this test device consists of a main controller 51 containing a host computer.
and a measurement unit 53 that is driven and controlled by a main controller 51 via a driver 52.

The measurement unit 53 is capable of applying an analog voltage or current to the object to be inspected 54 and measuring the output voltage or current from the object to be inspected. This measurement unit has a function of outputting an analog sweep voltage with a constant slope as shown in FIG. 6, and the following procedure is usually followed when generating such an output.

A table that increases at a constant sweep step (ΔV) from the sweep start voltage to the sweep end voltage is created on the data table built into the measurement unit, and a separate execution table is created by referring to this table.

In the execution table, the values of the sweep mode, sweep start table address, sweep last table address, and clock (which determines the sweep interval) are registered.

After such settings, when a trigger command is given to the measurement unit, a sweep operation is started according to the contents of the execution table, and analog sweep voltage output is started.

[Problems to be Solved by the Invention] In such a sweep voltage generation method, when generating sweep voltages with different sweep slopes (sweep step ΔV and sweep interval Δt), it is necessary to create separate tables for each. be.

However, due to memory constraints (e.g. 8K words for data table memory), it is not possible to create too many sweep tables (the total number of steps is limited to a maximum of 8192), and Another disadvantage is that it is necessary to create a sweep table each time immediately before a sweep, and as a result of performing such sweep table creation processing within a measurement sequence, the overall measurement speed decreases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sweep step signal generation method capable of handling a wide range of slope sweeps simply by having a data table.

[Means for solving the problems] In order to achieve such an objective, the present invention
Store specific sweep step data as a reference in the data table of the measurement unit, and set the reference data table based on the specified sweep start voltage, sweep end voltage, sweep step (ΔV), and sweep interval (Δt). The top, last, and clock of the address range are determined and stored in an execution table, and then when a trigger command is given, a sweep step signal is generated while referring to the data table based on each parameter in the execution table. It is characterized by the following.

[Example] The present invention will be described in detail below with reference to the drawings.
In the present invention, a reference sweep table is prepared in advance, and a desired sweep step signal is generated by referring to this table. Step interval (clock) when referring to the sweep table
Although Δt and sweep step ΔV are determined for each sweep, only the slope of the sweep step signal that is actually output is determined based on the step interval Δt and sweep step ΔV. Each step in the output signal is itself based on a step in the sweep table.

The sweep step signal generation method of the present invention will be explained below with reference to the flow shown in FIG.

First, create a data table. The data table starts from address 0 as shown in Figure 2.
By 8192, values that increase by 1 from -2048 to +2047 and values that decrease by 1 from +2047 to -2048 are stored separately. This value ranges from the final output voltage value of -1V to +0.9995V and +
Each corresponds to voltages from 0.9995V to -1V. The contents of this table are a reference table that is commonly used for all sweeps, and once set, there is no need to change the settings for each sweep as in the past.

Next, set the sweep start voltage and sweep end voltage, which determine the top and last of the sweep, the sweep step ΔV, and the sweep interval Δt.

From the sweep start voltage and sweep end voltage, the top and last addresses of the address range to be referenced in the data table are determined using the following equations.

Top = 2048 x (sweep start voltage) /
(Full scale value of range) Last = 2048 x (Sweep last voltage) / (Full scale value of range) Also, calculate the clock from the sweep step ΔV and sweep interval Δt using the following formula.

Clock = Δt/(ΔV/ΔV0 where V0 is the minimum resolution (fixed value) (0.49mV for 1V range) Store the top, last, and clock determined in this way in the execution table.

By providing a trigger command TRIG for executing a sweep, a sweep is initiated based on the parameters of the execution table, and a sweep step signal as shown in FIG. 3 is generated.

FIG. 4 is a block diagram showing an example of a measurement unit that implements the method of the present invention. Note that the configuration other than the measurement unit is the same as that shown in FIG. 5 as a conventional configuration. In FIG. 4, 1 is a data table, 2 is an arithmetic processing circuit, 3 is an execution table, 4 is a control circuit, and 5 is a digital-to-analog conversion circuit.

The arithmetic processing circuit 2 is an arithmetic processing section that performs the calculation of the top, last and clock. Note that the sweep start voltage, sweep end voltage, and sweep interval Δt required for top, last, and clock calculations are input by the operator from an input device such as a keyboard installed on the main controller, and are sent to the measurement unit via the driver. is input.

The top, last and clock determined by the arithmetic processing circuit 2 are stored in the execution table 3 under the control of the control circuit 4.

When a trigger command is input from the main controller, the control circuit 4 sequentially generates sweep step signals (digital values) based on the parameters of the execution table 3 and referring to the data table.
This value is converted into analog by the digital-to-analog conversion circuit 5 and applied to the object to be inspected (not shown).

[Effects of the Invention] As explained above, according to the present invention, it is only necessary to prepare one type of data table, and the desired sweep step signal can be obtained by changing only the execution table for each different sweep. can be generated.

Also, as a data table, -2048 to +2047
Since it is a simple data string table with two groups of +2047 to -2048, debugging etc. are easy.

Furthermore, since the sweep step is set to the minimum resolution of the digital-to-analog conversion circuit (for example, 0.49mV for the 1V range), smooth sweep output is possible.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the flow of the sweep step signal generation method according to the present invention, FIG. 2 is an explanatory diagram for explaining a data table, FIG. 3 is a diagram for explaining the parameters of the sweep step signal, and FIG. FIG. 4 is a block diagram showing an example of a measurement unit implementing the method of the present invention, FIG. 5 is a block diagram showing an example of a conventional test device, and FIG. 6 is an explanatory diagram regarding a sweep step signal. 1...Data table, 2...Arithmetic processing circuit,
3...Execution table, 4...Control circuit, 5...Digital-to-analog conversion circuit.

Claims (1)

[Claims] 1. A main controller with a built-in computer;
Equipped with a measurement unit driven by the main controller via a driver, the measurement unit generates a sweep step signal, converts it into digital/analog and outputs it, and when this is applied to the object to be inspected, In a test device that measures the output of the object through a measurement unit and determines the quality of the inspected object based on the measured value, specific sweep step data that serves as a reference is stored in the data table of the measurement unit, and the specified sweep step data is stored as a reference in the data table of the measurement unit. Based on the start voltage, sweep end voltage, sweep step (ΔV), and sweep interval (Δt), the top, last, and clock of the address range of the data table to be referenced are determined and stored in the execution table, and then the trigger command is given. 1. A method for generating a sweep step signal, characterized in that when a sweep step signal is generated, the sweep step signal is generated while referring to the data table based on each parameter of the execution table.