Chapter 6 Command Reference 205
NPLC
Syntax NPLC [power_line_cycles]
power_line_cycles
The primary use of the NPLC command is to establish normal mode noise
rejection (NMR) at the A/D converter's reference frequency (LFREQ command).
Any value
³1 for the power_line_cycles parameter provides at least 60 dB of NMR
at the power line frequency. Any value <1 provides no NMR; it only sets the
integration time for the A/D converter. The ranges and the incremental step sizes
for the power_line_cycles parameter are:
0 - 1 PLC in .000006 PLC steps for 6OHz reference frequency (LFREQ command)
or
0 - 1 PLC in .000005 PLC steps for 50Hz reference frequency
1 - 10 PLC in 1 PLC steps
10 - 1000 PLC in 10 PLC steps.
Power-on power_line_cycles = 10
Default power_line_cycles = 0 (selects minimum integration time of 500ns)
The relationship of the integration time (expressed in PLCs), the A/D converter's
reference frequency (LFREQ command), and the digits of resolution is:
* Analog measurement method only (SETACV ANA command)
** For all ranges except the 10W OHM(F) range and the 100mV DCV range. The 10W
OHM(F) range has a maximum of 6.5 digits and the 100mV DCV range has a
maximum of 7.5 range.
Remarks • For the ACV and ACDCV (SETACV ANA method only), ACT, ACDCI, DCI,
DCV, OHM, and OHMF measurement functions, resolution is determined by
the A/D converter's integration time. The integration time has no effect on FREQ
or PER. For sampled ACV or ACDCV (SETACV SYNC or SETACV RNDM),
the integration time is selected automatically and the specified resolution is
achieved by varying the number of samples taken. For direct- or sub-sampled
digitizing, the integration time is fixed and cannot be changed.
• Since the NPLC and APER commands both set the integration time, executing
either will cancel the integration time previously established by the other. The
RES command or the %_resolution parameter of a function command or the
RANGE command can also be used to indirectly select an integration time. An
Digits of Resolution Power Line Cycles (NPLC command)
DCV
DCI,
OHM
(F)
ACI, ACDCI,
ACV*,
ACDCV*
Reference
Frequency
(LFREQ) = 60HZ
Reference Frequency
(LFREQ) = 50HZ
4.5 4.5 4.5 0 - .000030 0 - .000025
5.5 5.5 5.5 .000036 - .000360 .000030 - .000300
6.5 6.5 6.5 .000366 - .030000 .000305 - .025000
7.5 7.5** 6.5 .030006 - 1 .025005 - 1
8.5** 7.5** 6.5 2 - 1000 2 - 1000
To Next Page
Loading...
Need help?
General
