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Appendix E, ALPHABETICAL LISTING OF COMMANDS
\N n
N
NC
NHZ.
NN[.]
E-12
Address command
When the 7220 is daisy-chained with other compatible instruments this command will
change which instrument is addressed. All daisy-chained instruments receive
commands but only the currently addressed instrument will implement or respond to
the commands. The exception is the \N n command. If n matches the address set from
the front panel the instrument will switch into addressed mode. If n does not match
the address set from the front panel the instrument will switch into unaddressed mode.
Note: The \N n command does not change the address of an instrument but which
instrument is addressed.
Warning: All instruments must have a unique address.
Report overload byte
Causes the lock-in amplifier to respond with the overload byte.
Bit 0
not used
Bit 1
CH1 output overload (> ±120 %FS)
Bit 2
CH2 output overload (> ±120 %FS)
Bit 3
Y output overload (> ±300 %FS)
Bit 4
X output overload (> ±300 %FS)
Bit 5
not used
Bit 6
input overload
Bit 7
reference unlock
New curve
Initializes the curve storage memory and status variables. All record of previously
taken curves is removed.
Causes the lock-in amplifier to respond with the square root of the noise spectral
density measured at the Y output, expressed in volt/√Hz or amp/√Hz referred to the
input. This measurement assumes that the Y output is Gaussian with zero mean.
(Section 3.10). The command is only available in floating point mode.
This command is not available when the reference frequency exceeds 60 kHz.
Noise output
In fixed point mode causes the lock-in amplifier to respond with the mean absolute
value of the Y output in the range 0 to 12000, full-scale being 10000. If the mean
value of the Y output is zero, this is a measure of the output noise.
In floating point mode causes the lock-in amplifier to respond in volts.
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