XT2640 Operating Manual
13 July 2016
Page 83 of 187
17.1.1.1
RECOMMENDED
LF/PERIOD
SETTING
The XT2640 performs one “sample” every measurement period, so to strictly accommodate the requirement of EN50564:2011 para.
5.3.2 that there must be at least one sample per second the VPA must be configured for a LF/PERIOD setting of either 10Hz/0.3s,
20Hz/0.1s or 45Hz/20ms.
Recommendation:
Generally, the 20Hz/0.1s setting is recommended for LF/PERIOD which exceeds the requirement by a factor of 10:1;
however for shorter low power measurements, or where the load is known to have fast excursions in power, the
45Hz/20ms setting should be considered.
17.1.1.2
RECOMMENDED
FUND
SETTING
EN50564 measurements are normally performed on mains power.
Recommendation:
Generally, the MAINS setting for FUND is recommended.
17.1.1.3
RECOMMENDED
BANDWIDTH
SETTING
EN50564:2011 para. 4.4.2 requires that power measurement be made with “
a
frequency
response
exceeding
2KHz
”.
Recommendation:
Generally, the AUTO‐TRACK setting for BANDWIDTH is recommended which fully meets this requirement.
17.1.1.4
RECOMMENDED
HARMONICS
SETTING
EN50564:2011 para. 4.3.2 requires limits on the THD of the voltage source and requires that this THD shall be computed using up to
and including the 13
th
harmonic.
Recommendation:
The setting should be at least 13 for HARMONICS.
Note:
The reported voltage THD on the STBY POWER screen only includes up to the 13
th
harmonic no matter what HARMONICS
is set to as long as it is set to at least 13.
17.1.1.5
RECOMMENDED
ADJUST
SETTING
EN50564:2011 Appendix D requires that the error introduced by the shunt be accounted for in the total error figures or be
otherwise compensated for. EN50564:2011 Appendix B discusses two methods of connecting the power analyzer and the load.
Recommendation:
It is recommended that the “
Lower
Power
Loads
” connections described in EN50564:2011 B.4.2 (which is the method when
using accessory LPA‐1) is used. Use a setting of LOAD(V@SRCE) for ADJUST to compensate for this wiring method.
The small inaccuracy of the compensation is included in the reported error figure.
17.1.2
LOW
POWER
MEASUREMENT
CONFIGURATION
The low power measurement itself is configured by pressing the CONFIGURE button on the STBY POWER screen.