PQM-700 Operating Manual
66
7.2
Sampling and RTC
Sampling and RTC
A/D converter
16-bit
Sampling rate
10.24 kHz for 50 Hz and 60 Hz
Simultaneous sampling in all channels
Samples per period
204.8 for 50 Hz; 170.67 for 60 Hz
PLL synchronization
40..70Hz
Reference channel for PLL
L1/A
Real-time clock
3.5 ppm max (approx.
9 sec./month)
in the temperature range of -20
C…+55
C
7.3
Measured parameters - accuracy, resolution and ranges
7.3.1 Reference conditions
Tab. 5. Reference conditions.
Reference conditions
Ambient temperature
23
C
2
C
Relative Humidity
40…60%
Voltage unbalance
≤ 0.1% for unbalance factor of negative sequence (applies only to 3-phase
systems)
External continuous magnetic field
≤ 40 A / m DC
≤ 3 A / m AC for 50/60 Hz frequency
DC component of voltage and current
none
Waveforms
sinusoidal
Frequency
50
Hz ±0.2% or 60 Hz ±0.2%
7.3.2 Voltage
Voltage
Ranges and conditions
Resolution
Basic uncertainty
U
RMS
(AC+DC)
20% U
nom
≤ U
RMS
≤ 120% U
nom
for U
nom
≥ 100 V
0.01% U
nom
0.5% U
nom
Crest Factor
1..10 (1..1.65 for 690 V voltage)
for U
RMS
≥ 10% U
nom
0.01
5%
7.3.3 Current
Current
Ranges and condi-
tions
Resolution
Basic uncertainty
I
RMS
(AC+DC)
Input path without clamps
0..1V (0..3.6V
p-p
)
0.01% I
nom
1% I
nom
Flexible clamps F-1(A)/F-2(A)/F-3(A)
0..3000 A
(10 kA
p-p
)
0.01% I
nom
Additional uncertainty
1%
(
2% taking into account additional
error due to the position)
CT clamps C-4(A)
0..1000 A
(3600 A
p-p
)
0.01% I
nom
Additional uncertainty
0.1..10 A:
(3% + 0.1 A)
10 A:
3%
50 A:
1.5%
200 A:
0.75%
1000..1200 A:
0.5%
Summary of Contents for PQM-700
Page 85: ...85 Notes...
