Section 1
OM6530-C1-00
19 November, 2019
1-4
Unknown currents can be measured by connecting the unknown current source output
directly to the integrator input (the internal test voltage source is not used when
measuring currents).
The stability of the Model 6530 depends on the stability of the applied test voltage, the
integrator, the timing circuit and the threshold voltage detector at the integrator output.
The fixed deviations in the absolute values of these parameters are compensated during
calibration by using a software calibration routine in conjunction with a set of external
calibration resistors of known value. Guildline manufactures 9336 and 9337 calibration
resistors that are ideally suited for this purpose. Guildline also manufactures a 6636
Temperature Stabilized Resistor set that is suited to calibrate the 6530 in environments
where the temperature is not regulated to laboratory standards.
The Model 6530 is fully automated with an internal microprocessor to compute the
measurements and make the deviation compensations. The microprocessor can be
operated from the front panel manual controls or from either one of the two
communication control buses. The calculated value of the unknown resistor is displayed
on the front panel and is made available to instruments attached to either control bus.
The Model 6530 provides increased accuracy through integrated filtering options and
taking measurements with test voltage polarity alterations. The computed average is
displayed on the front panel and is made available to instruments on the control bus
(GPIB or RS-232C).
1.1.3.
MODES OF OPERATION
The Model 6530 is fully automated for simplicity and convenience. When specific
measurement parameters are required the operator (or instruments on the control bus) can
manually configure the 6530.
The instrument can be set to take a continuous series of measurements or to take one
measurement for each sample request. A sample request can be made with an external
synchronizing signal fed to a rear panel connector or by the operator pressing a front
panel function key/push-button.
The number of resistance measurements made per data sample output (averaged), is user
selectable. The resistance test voltage polarity is selectable. When measuring current,
both polarities can also be accommodated by this selection.
The SOFCAL (software calibration) function permits the operator to calibrate the
instrument and edit the calibration date and the serial number of the instrument.
