89
STEP 88
CH2 Fall time (2)
Adjust for 40us
STEP 89
CH2 Square-wave symmetry 50%
Adjust for 50us ± 0.1us
STEP 90
CH2 Square-wave symmetry 75%
Adjust for 75us ± 0.1us
STEP 91
CH2 Square-wave symmetry 25MHz
Adjust for 50% ± 1%
STEP 92
CH2 Square-wave symmetry 35MHz
Adjust for 50% ± 1%
STEP 93
CH2 Square-wave symmetry 43MHz
Adjust for 50% ± 1%
STEP 94
CH2 Square-wave symmetry 50MHz
Adjust for 50% ± 1%
STEP 95
MOD offset
Adjust for 5V ± 50mV
STEP 96
MOD full scale
Adjust for 8V ± 50mV
STEP 97
Ref clock calibration
Adjust for 10·00000 MHz ± 1ppm
Remote Calibration
Calibration of the instrument may be performed over the LAN, USB or GPIB interface. To
completely automate the process the multimeter, oscilloscope and universal counter will also need
to be remote controlled and the controller will need to run a calibration program unique to this
instrument.
The remote calibration commands allow a simplified version of manual calibration to be performed
by issuing commands from the controller. The controller must send the CALADJ command
repeatedly and read the dmm or frequency meter until the required result for the selected
calibration step is achieved. The CALSTEP command is then issued to accept the new value and
move to the next step.
While in remote calibration mode very little error checking is performed and it is the controllers
responsibility to ensure that everything progresses in an orderly way. Only the following commands
should be used during calibration.
WARNING: Using any other commands while in calibration mode may give unpredictable results
and could cause the instrument to lock up, requiring the power to be cycled to regain control.
CALIBRATION <cpd>, [nr1]
: The calibration control command. <cpd> can be one of three
sub
−
commands:
−
START - Enter calibration mode; this command must be issued before any
other calibration commands will be recognised.
SAVE - Finish calibration, save the new values and exit calibration mode.
ABORT - Finish calibration, do not save the new values and exit calibration
mode.
[nr1] represents the 4-digit calibration password. The password is only
required with CALIBRATION START and then only if a non
−
zero password
has been set from the instrument’s keyboard. The password will be ignored,
and will give no errors, at all other times.
It is not possible to set or change the password using remote commands.
CALADJ <nr1>
Adjust the selected calibration value by <nr1>. The value must be in the
range
−
100 to +100. Once an adjustment has been completed and the new
value is as required the CALSTEP command must be issued for the new
value to be accepted.
CALSTEP
Step to the next calibration point.
CALVAL?
Returns the value from level calibration. Valid for steps 13 to 27 only
otherwise returns -1
For general information on remote operation and command formats, refer to the following sections.
