INStalled
: Channel subcommand that provides a query response only. When queried the command returns a comma
delimited field with information pertaining to the specified channel. The fields returned are channel type (or
option), current filter setting, current amplifier setting, current wavelength setting,
OE-2
Channel Status
(Single/Dual), and
OE-2
release (B01.00 – Beta 1.00, R01.00 Production 1.00). Example read: ‘:CHAN1:INS?’.
NULLoffset
: Channel subcommand that sets or reads the null offset of the specified channel. The null offset value
is computed from a calibration that is performed when the specified channel’s optical input is dark. The null
offset is then used to compensate the power monitor for this ‘null’ condition. When performing a NULL Offset
calibration the selected units must be BITS. The null offset value should be cleared (set to 0) before the
calibration is started. See the calibration example under the CALIBRATE root command.
TYPE
: Channel subcommand that provides a query response only. The type (or option) of the
OE-2
channel is
returned in a ‘/’ delimited field. The return string contains the filter positions that are available for the specified
channel. Valid strings are given in the chart above. Example read: ‘:CHAN1:TYPE?’.
WAVElength
: Channel subcommand that set the wavelength for the specified channel or reads the current setting.
The wavelength setting determines the calibration constant that is used in the average power measurement. Any
wavelength setting that does not match the input optical wavelength will result in an incorrect average power
reading. Wavelength units are meters. Example write: ‘:CHAN1:WAVE 1550E-9’.
SYSTEM
: Root command for system wide commands.
ADFormat
: System subcommand that sets or reads the current A/D format. When set to BITS the AVEP command
returns the counts from the A/D converter in the power monitor circuit. VOLTS specifies the voltage at the
input of the A/D converter. AMPS specifies the current flowing into the O/E receiver. WATTS specifies the
OE-2 input average optical power. The BITS setting is used for NULL calibration. The VOLTS/AMPS settings
are used in the factory. The WATTS setting is the default.
CALIBRATE
: Root command for calibration commands.
CALType
: Calibrate subcommand that sets or reads the current calibration type. A short calibration does not
require any external readings but may be less accurate than a long cal. During a long cal the ADFormat is set to
BITS and readings are taken with the AVEPwr command. The readings can be averaged over several seconds
to improve the accuracy of the calibration. The averaged value (in BITS) is then written using the NULLoffset
command. Example Cal sequence:
Short Cal:
:CAL:CALT SHORT
:CHAN1:NULL
Long Cal:
:CAL:CALT LONG (set long cal mode)
:SYSTEM:ADFORMAT BITS (set format to BITS)
:CHAN1:NULL 0 (Zero out the current null)
:CHAN1:AVEP? (Read this multiple times over a period of several seconds and average the results)
:CHAN1:NULL <AVERAGED DATA> (write the averaged data)
:SYSTEM:ADFORMAT WATTS (return format to WATTS)
| APPENDIX B | GPIB Commands
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