Ametek 7230 Instruction Manual page 150

Appendix E, ALPHABETICAL LISTING OF COMMANDS
FMCENTERV[.] [n]
FMFILTER [n]
FMSPANF[.] [n] Oscillator frequency modulation span frequency command
FMVSPAN[.] [n] Oscillator frequency modulation voltage span command
FRQ[.]
FSTART[.] [n]
E-12
Oscillator frequency modulation center voltage command
The value of n sets the oscillator frequency modulation center voltage; in fixed point
mode n is an integer in the range -10000 to +10000, corresponding to voltages from -
10.000 V to +10.000 V, and in floating point mode it is in volts.
NOTE: The span voltage plus the center voltage cannot exceed
Oscillator frequency modulation filter control command
The value of n sets the oscillator frequency modulation voltage low-pass filter
control in the range 0 to 10. The value of 0 gives the widest bandwidth for this filter,
with the value of 10 the lowest.
In fixed point mode n sets the oscillator frequency-modulation span frequency in
millihertz. The range of n is 0 to 60000000 or 125000000 representing 0 to ± 60 kHz
or 125 kHz; in floating point mode n sets the span frequency in the range 0 to 6.0E4
or 1.25E5.
Note: The center frequency
limits of the oscillator (0 to 120 or 250 kHz). Hence the center frequency plus the
span frequency cannot exceed 120.0 or 250.0 kHz and the center frequency must
be greater than or equal to the span frequency. For example, with an instrument
fitted with the 7230/99 upper frequency extension option and a 125 kHz center
frequency the maximum span frequency is
the maximum span frequency is
maximum span frequency is also
span frequency under computer control it is recommended to first set the span
frequency to zero followed by the center frequency to the required value and
finally the span frequency to the required value. This will avoid potential problems
with the new center frequency being rejected because it is not a legal value when
compared with the old span frequency.
The value of n sets the oscillator frequency modulation span voltage; in fixed point
mode n is an integer in the range 0 to +10000, corresponding to a range from
0.000 V to 10.000 V, and in floating point mode it is in volts.
NOTE: The span voltage plus the center voltage cannot exceed
Reference frequency meter
If the lock-in amplifier is in the external reference source modes, the FRQ command
causes the lock-in amplifier to respond with 0 if the reference channel is unlocked, or
with the reference input frequency if it is locked.
If the lock-in amplifier is in the internal reference source mode, it responds with the
frequency of the internal oscillator.
In fixed point mode the frequency is in mHz, and in floating point mode the
frequency is in Hz.
Oscillator frequency sweep start frequency
Sets the start frequency for a subsequent sweep of the internal oscillator frequency,
in the range 0 to 120 or 250 kHz.

the span frequency must not exceed the frequency

125 kHz; at 10k Hz center frequency

10 kHz; at 240 kHz center frequency the

10 kHz. When setting the center frequency and

10.000 V

10.000 V