XITRON 2000I, Руководство пользователя

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2000I & 2000M User Guide, Rev B
Performing Internal and External Calibrations
Calibration is initiated via the MNU key. Refer to the Maintenance and
Calibration chapter.
Range Locking
The F.02 firmware provides “Range Lock” mode for the 20VDC and 2VDC,
as well as for the 20mA DC current range. These range locking features
provide more functionality for calibration and testing of diverse circuits such
as control loops and A/D converters. In locked range mode, the
accuracy/offset/resolution specifications for the selected range apply for all
entered output levels, including those which would normally invoke a lower
range. For precise testing with extremely small output levels. It is
recommended to unlock the instrument to allow operation in Auto-Range
mode.
The “Range Lock” mode can be selected by stepping through the menu,
similar to the operation of all earlier firmware versions. The three possible
locked ranges, 20V, 2V, and 20mA, will appear in sequence. With the desired
range on the display, pressing any one of the Units/Enter keys will lock the
instrument in the shown range. Unlocking the ranges can be accomplished in
a similar fashion.
When in locked 20V or 20mA range, output levels below 2.2V respectively
2.2mA, will not cause the instrument to range down. Similarly, when in 2.0V
locked range, the instrument will not range down when programmed to output
levels below 0.22V. The full ranges are continuous therefore, without the
level switching that would occur in auto-range mode. Range locking can be
made the default (power-up) mode by selecting the “Set Defaults” menu
choice.
When in 2.0V locked range, the output level cannot exceed 2.2V, irrespective
of the entered value. As before, when programming values which exceed the
instrument's output level capability, the 2000 instruments will automatically
go to “Standby” operation, as these level request are illegal commands.
Version F.02 accepts 22mA as a valid output level, where earlier firmware
versions would only accept output current commands up to 21.999mA.