User Manual

18-108 SCPI Command Reference 2400 Series SourceMeter
®
User’s Manual
command, user setup recall (*RCL), or a source memory recall
(:SOUR:MEM command or during a source memory sweep), NPLC
caching will occur. If the integration rate is already stored in the
cache, the stored reference and zero values are recalled and used.
Otherwise, a reference and zero value are acquired and stored in the
cache. If there are already 10 NPLC values stored, the oldest one
will be overwritten by the newest one.
Follow these general steps to program and use NPLC caching:
1. Send this command to disable auto zero: SYST:AZER OFF.
2. Enable NPLC caching by sending: SYST:AZER:CACH ON.
3. Set up and run your source memory sweep with the
:SOUR:MEM commands along with the various other commands
required to program additional operating modes. (See “
Config-
ure memory sweep,” as well as other pertinent command
descriptions in this section, for details.)
NOTE Auto zero should be disabled with the :SYST:AZER OFF command for maxi-
mum source memory sweep speed; otherwise, the cache is of little use. With
auto zero enabled, new A/D reference and zero values are taken for every
reading and saved into the cache, slowing down sweep operation. However,
with auto zero disabled, measurements may drift and become erroneous. To
minimize drift when using NPLC caching with auto zero disabled, periodically
send :SYST:AZER ONCE to force an immediate auto zero update.
Select power line frequency setting
LFRequency <freq>
:SYSTem:LFRequency <freq> Select line frequency
Parameters <freq> = 50 50Hz or 400Hz setting
60 60Hz setting
Query :LFRequency? Query line frequency selection.
Description Use this command to manually select the line frequency setting (50
or 60Hz). For 400Hz operation, select 50Hz.
AUTO <b>
:SYSTem:LFRequency:AUTO <b> Control auto line frequency selection
Parameters <b> = 1 or ON Enable and line frequency selection
0 or OFF Disable auto line frequency selection
Query :AUTO? Query state of auto line frequency selection.
Description This command is used to enable or disable auto line frequency
detection. When enabled, the SourceMeter will sense the line fre
-
quency on power-up and select the appropriate line frequency set-
ting. Manually setting the line frequency disables auto frequency.
(See previous command.)