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E-10
Appendix E, ALPHABETICAL LISTING OF COMMANDS
LF [n] Signal channel line frequency rejection filter control
In instruments manufactured prior to June 1996, the value of n sets the mode of the
line frequency notch filter according to the following table:
n Selection
0Off
1 On (i.e. reject 50/60 Hz and 100/120 Hz)
In instruments manufactured after June 1996, the value of n sets the mode of the line
frequency notch filter according to the following table:
n Selection
0Off
1 Enable 50 or 60 Hz notch filter
2 Enable 100 or 120 Hz notch filter
3 Enable both filters
Users may identify which version of the instrument they have by sending the
command LF 3; if this is accepted by the instrument, it was made after June 1996,
but if it generates a command error, it was made prior to this date.
Units made after June 1996 respond in addition to the command, LINE50, which sets
the notch filter centre frequency.
LINE50 [n] Signal channel line frequency rejection filter centre frequency control
The value of n sets the line frequency notch filter centre frequency according to the
following table:
n Notch filter mode
0 60 Hz (and/or 120 Hz)
1 50 Hz (and/or 100 Hz)
Units made prior to June 1996 generate an Invalid Command (bit 1 of the serial poll
status byte is asserted) to the LINE50 command.
LOCK System lock control
Updates all frequency dependent gain and phase correction parameters.
LR[.] Log ratio output
In integer mode, the LR command reports a number equivalent to
1000 log (X / ADC1) where X is the value that would be returned by the X command
and ADC1 is the value that would be returned by the ADC1 command. The response
range is - 3000 to +2079.
In floating point mode, the LR. command reports a number equivalent to
log (X / ADC 1). The response range is -3.000 to +2.079.