Keithley 2700 User Manual

3-16 Basic DMM Operation Model 2700 Multimeter/Switch System User’s Manual
Widely varying temperatures within the circuit can also create thermal EMFs. Therefore,
maintain constant temperatures to minimize these thermal EMFs. A shielded enclosure
around the circuit under test also helps by minimizing air currents.
The REL control can be used to null out constant offset voltages.
AC voltage offset
The Model 2700, at 5H digits resolution, will typically display 100 counts of offset on AC
volts with the input shorted. This offset is caused by the offset of the TRMS converter.
This offset will not affect reading accuracy and should not be zeroed out using the REL
feature. The following equation expresses how this offset (V
OFFSET
) is added to the signal
input (V
IN
):
Example: Range = 1VAC
Offset = 100 counts (1.0mV)
Input = 100mV RMS
= 0.100005 V
The offset is seen as the last digit, which is not displayed. Therefore, the offset is
negligible. If REL were used to zero the display, the 100 counts of offset would be
subtracted from V
IN
, resulting in an error of 100 counts in the displayed reading.
Displayed reading V
IN
()
2
V
OFFSET
()
2
+=
Displayed reading 100mV()
2
1.0mV()
2
+=
Displayed reading 0.01V 1 10
6–
V×()+=

Keithley 2700 Specifications

General

Type	Digital Multimeter
Measurement Functions	DC Voltage, AC Voltage, DC Current, AC Current, Resistance, Frequency, Temperature
DC Voltage Range	100 mV to 1000 V
AC Voltage Range	100 mV to 750 V
Frequency Range	3 Hz to 500 kHz
Temperature Range	-200°C to +1372°C
Display	Vacuum Fluorescent Display
Connectivity	IEEE-488, RS-232
Channels	10
Power Supply	100V to 240V AC, 45Hz to 66Hz
DC Current Range	10 µA to 3 A
AC Current Range	10 µA to 3 A
Temperature Measurement	Thermocouple, RTD