Manual

The CMC 256plus is the first choice for applications requiring very high accuracy. This unit is
not only an excellent test set for protection devices of all kinds but also a universal calibra-
tion tool. Its high precision allows the calibration of a wide range of measuring devices,
including: electricity meters of class 0.2, measuring transducers, power quality measurement
devices and phasor measurement units (PMU). Its unique accuracy and flexibility make the
CMC 256plus ideal for protection and measurement equipment manufacturers for research
and development, production and type testing. The CMC 256plus can either be operated by
the Test Universe software running on a PC or by the front panel control device CMControl.
CMC 256plus: 6 Phase Current + 4 Phase Voltage Test Set and Universal Calibrator
Current generators
Setting range 6-phase AC (L-N)
6 x 0 ... 12.5 A
3-phase AC (L-N)
3 x 0 ... 25 A (Group A II B)
1-phase AC (3L-N)
1 x 0 ... 75 A (Group A II B), 2 x 0 ... 37.5 A
DC (3L-N)
1 x 0 ... ±35 A (Group A II B), 2 x 0 ... ±17.5 A
Power 6-phase AC (L-N)
6 x 80 VA typ. at 8.5 A, 6 x 70 VA guar. at 7.5 A
3-phase AC (L-N) 3 x 160 VA typ. at 17 A (Group A II B)
3 x 140 VA guar. at 15 A (Group A II B)
1-phase AC (3L-N) 1 x 480 VA typ. at 51 A (Group A II B),
2 x 240 VA at 25.5 A
1 x 420 VA guar. at 45 A (Group A II B),
2 x 210 VA at 22.5 A
1-phase AC (L-L) 1 x 320 VA typ. at 8.5 A (Group A II B),
2 x 160 VA at 8.5 A
1 x 280 VA guar. at 15 A (Group A II B),
2 x 140 VA at 7.5 A
1-phase AC (L-L-L-L) 1 x 320 VA typ. at 8.5 A
(40 VRMS, Group A and B in series)
1 x 280 VA guar. at 7.5 A
(40 VRMS, Group A and B in series)
DC (3L-N) 1 x 480 W typ. at ±35 A (Group A II B),
2 x 240 W at ±17.5 A
1 x 470 W guar. at ±35 A (Group A II B),
2 x 235 W at ±17.5 A
500
400
300
200
100
0
0 10 25 50 75
Output current / A
Group A
and B in
series
1-phase
AC (L-L)
3-phase AC (L-N)
1-phase AC (L-N)
Output power (typ.) / VA
Accuracy
2
error < 0.015 % rd.
3
+ 0.005 % rg.
3
typ.
at 0 ... 12.5 A
error < 0.04 % rd. + 0.01 % rg. guar.
at 0 ... 12.5 A
Distortion (THD+N)
4
< 0.025 % typ., < 0.07 % guar.
Ranges 1.25 A / 12.5 A (Group A, B) or
2.5 A / 25 A (Group A II B)
Resolution (for respective range)
50 µA / 100 µA / 500 µA / 1 mA
Max. compliance voltage (L-N)/(L-L)
15 Vpk / 60 Vpk
Connection 4 mm (0.16 in) banana sockets / combination
socket (Group A only)
Voltage generators
Setting range 4-phase AC (L-N) 4 x 0 ... 300 V (VL4(t) automatically
calculated: VL4 = (VL1+VL2+VL3)*c
or freely programmable)
3-phase AC (L-N) 3 x 0 ... 300 V
1-phase AC (L-L) 1 x 0 ... 600 V
DC (L-N) 4 x 0 ... ±300 V
Power 3-phase AC (L-N) 3 x 100 VA typ. at 100 ... 300 V
3 x 85 VA guar. at 85 ... 300 V
4-phase AC (L-N) 4 x 75 VA typ. at 100 ... 300 V
4 x 50 VA guar. at 85 ... 300 V
1-phase AC (L-N) 1 x 200 VA typ. at 100 ... 300 V
1 x 150 VA guar. at 75 ... 300 V
1-phase AC (L-L) 1 x 275 VA typ. at 200 ... 600 V
1 x 250 VA guar. at 200 ... 600 V
DC (L-N) 1 x 420 W typ. at ±300 V
1 x 360 W guar. at ±300 V
Output voltage / V
Output power (typ.) / VA
1-phase AC (L-L)
1-phase AC (L-N)
3-phase AC (L-N)
4-phase AC (L-N)
300
250
200
150
100
50
0
0 100 200 300 400 500 600
Accuracy
5
error < 0.015 % rd.
3
+ 0.005 % rg.
3
typ. at 0 ... 300 V
error < 0.04 % rd. + 0.01 % rg. guar.
at 0 ... 300 V
Distortion (THD+N)
4
0.015 % typ., < 0.05 % guar.
Ranges 150 V / 300 V
Resolution 5 mV / 10 mV in range 150 V / 300 V
Connection 4 mm (0.16 in) banana sockets /
combination socket (1,2,3,N)
Generators, general
Frequency range sine signals 10 ... 1000 Hz
range harmonics /
interharmonics
6
10 ... 3000 Hz
range transient signals
6
DC ... 3.1 kHz
accuracy / drift ±0.5 ppm / ±1 ppm
resolution < 5 µHz
Phase angle range -360° ... +360°
resolution 0.001°
error at 50 / 60 Hz < 0.005° typ., < 0.02° guar.
Bandwidth (-3 dB) 3.1 kHz
Simulated power
S, P (calibration
of energy meters)
accuracy
7
error < 0.05 % rd. typ., < 0.1 % rd.
guar.
temperature drift < 0.001 % / °C typ., < 0.05 % / °C guar.
Technical Data
1
1
All data specified are guaranteed, except where indicated otherwise.
OMICRON guarantees the specified data for one year after factory calibration,
within 23 °C ±5 °C (73 °F ±10 °F) in the frequency range from 10 to 100 Hz and
after a warm-up phase > 25 minutes
2
Rload: 0 ... 0.5 W
3
rd. = reading, rg. = range
4
THD+N: Values at 50/60 Hz, > 1 A / 20 V with 20 kHz bandwidth
5
Rload: > 250 W
6
Amplitude derating at > 1000 Hz
7
Data are valid from 0.1 to 12.5 A (current amplifier A or B) and 50 to 300 V
(voltage amplifier) at 50/60 Hz
Permissible load for current outputs:
Range 1.25 A: 0 to 1 W and 1 VA max., cos ϕ = 0.5 to 1
Range 12.5 A: 0 to 0.5 W and 6 VA max., cos ϕ = 0.5 to 1
Permissible load for voltage outputs:
10 VA max. at 50 to 300 V, cos ϕ = 0.5 to 1
CMC 256plus