ADC 100 Specifikace stáhnout pdf (Strana 9)

specify the printer port that is connected to the ADC-100

take a single reading from a specified channel

specify a trigger event from a specified channel (only available in block mode)

collect a block of samples at fixed time intervals from one or more channels

You can specify a sampling interval from 10us to a second. If you specify an interval that is shorter than

your computer can manage, the driver will tell you how long it will actually take to collect the specified

number of samples. After allowing for this, the timing accuracy under DOS is better than 1% for a block of

1000 samples at all sampling rates.

Under Windows, if you connect the product to the computer via a PICO USB parallel port, timing is

completely reliable. However, if you connect the product to the computer via the printer port, the sampling

may be affected by Windows activities. At the least, there will be gaps in the data every 55 milliseconds

due to the Windows timer function. There will be additional gaps if you move the mouse, or have other

programs running. We therefore recommend using the adc100_get_values_and_times routine, so that

you can determine the exact time that each reading was taken.

The normal calling sequence to collect a block of data is as follows:

Check that the driver version is correct

Open the driver

Set trigger mode (if required)

Set sampling mode (channels and time per sample)

While you want to take measurements,

Run

While not ready

Wait

End while

Get a block of data

End While

Close the driver

Scaling

The ADC-100 and ADC-101 are 12-bit analog to digital converters. This means that they produce values in the

range 0 to 4095 to represent the currently selected input voltage range. To convert from ADC readings to Volts,

you should subtract half of the 2048, multiply by the currently selected voltage range and divide by 2048. Thus,

on the 5V range, an ADC reading of 3135 represents (3135-2048) x 5 / 2048 = 2.654 Volts.

adc100_get_driver_version

PREF1 short PREF2 adc100_get_driver_version (void);

This routine returns the version number of the ADC100/101 driver. You can use it to check that your

application is used only with the driver version that it was designed for use with.

Generally speaking, new driver versions will be fully backward compatible with earlier versions, though the

converse is not always true, so it should be safe to check that the driver version is greater than or equal to

the version that it was designed for use with.

The version is a two-byte value, of which the upper byte is the major version and the lower byte is the

minor version.

adc100_open_unit

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ADC 100 Specifikace Strana 9