And Y Output Curve Storage Measurement - Ametek 7280 Instruction Manual

FLOAT 1
LF 0
OA. 1.0E0
OF. 100.0
SEN 27
TC 14
AQN
The frequency sweep would be performed and the outputs recorded by sending the
following commands from a FOR...NEXT program loop:
OF. XX
MAG.
PHA.
FRQ.
until the stop frequency is reached.
6.5.04 X and Y Output Curve Storage Measurement
In this example, the lock-in amplifier is measuring a current input signal applied to
the B input connector and the measured X channel output and Y channel output are
recorded for 10 seconds at a 100 Hz sampling rate. The acquired curves as read back
to the computer are required in floating point mode.
The sequence of commands is therefore as follows:
IE 2
IMODE 1
AUTOMATIC 1
FLOAT 1
LF 0 0
SEN 18
TC 14
AQN
Now the curve storage needs to be set up:
NC
CBD 19
LEN 1000
STR 10
The data is acquired by issuing:
TD
Float input connector shell using 1 kΩ to ground
Turn off line frequency rejection filter
Set oscillator amplitude to 1.0 V rms
Set oscillator frequency to 100 Hz (starting frequency)
Set sensitivity to 1 V full-scale
Set time constant to 50 ms
Auto-Phase
Set oscillator frequency to new value XX hertz
Software delay of 200 ms (4 × 50 ms) allowing output to
stabilize
Read Magnitude in volts
Read Phase in degrees
Read reference frequency in hertz. This would be same as
the oscillator frequency since the unit is operating in
the internal reference mode.
Set reference mode to external front panel input
Normal current input mode
AC Gain control automatic
Float input connector shell using 1 kΩ to ground
Turn off line frequency rejection filter
Set sensitivity to 1 nA full-scale
Set time constant to 50 ms
Auto-Phase
Clear and reset curve buffer
Stores X channel output, Y channel output and sensitivity
(i.e. bits 0, 1 and 4)
Number of points = 100 Hz × 10 seconds
Store a point every 10 ms (1/100 Hz)
Acquires data
Chapter 6, COMPUTER OPERATION
6-37