Keithley 2701 User Manual

Model 2701 User’s Manual Basic DMM Operation 3-5
LSYNC (line cycle synchronization)
Synchronizing A/D conversions with the frequency of the power line increases common
mode and normal mode noise rejection. When line cycle synchronization is enabled, the
measurement is initiated at the first positive-going zero crossing of the power line cycle
after the trigger.
Figure 3-1 shows the measurement process that consists of two A/D conversions. If the
trigger occurs during the positive cycle of the power line (Trigger #1), the A/D conversion
starts with the positive-going zero crossing of the power line cycle. If the next trigger
(Trigger #2) occurs during the negative cycle, then the measurement process also starts
with the positive-going zero crossing.
Figure 3-1
Line cycle synchronization
Perform the following steps to enable or disable line cycle synchronization:
1. Press SHIFT and then LSYNC to display the present state of line synchronization
(OFF or ON).
2. Use the
 or  key to display “LINESYNC ON” or “LINESYNC OFF.”
3. Press ENTER. The instrument returns to the normal display state.
NOTE Line synchronization is not available for the AC functions (ACV, ACI, FREQ, or
PERIOD) and for integration rates <1 PLC, regardless of the LSYNC setting.
1 PLC
A/D
Conversion
A/D
Conversion
Trigger
# 1
Trigger
# 2
Reading
Done
Reading
Done

Keithley 2701 Specifications

General

Max Voltage	300 V
Max Current	3 A
Frequency Range	3 Hz to 500 kHz
Frequency Accuracy	0.01%
Weight	3.6 kg
Measurement Functions	Frequency, Temperature
Interface	IEEE-488 (GPIB), RS-232
DC Voltage Range	300 V
DC Current Range	3 A
AC Voltage Range	300V
AC Current Range	1 μA to 3 A
Resistance Accuracy	0.01%
Channels	10
Dimensions	213mm x 88mm x 370mm