Atec WT200 User Manual

Specifications

Input

Input circuit type

Rated inputs (range)

Equipment loss (input resistance)

Instantaneous maximum allowable
input for one cycle, 20 ms

Instantaneous maximum allowable
input for 1 sec.

Continuous maximum allowable input

Continuous maximum common-mode
voltage (at 50/60 Hz input)

Common-mode rejection ratio at 600 Vrms
between input terminal and case

Input terminals
A/D conversion
Range switching
Automatic range switching

Measurement mode switching

Notes: Direct input and external sensor input of current cannot be used simultaneously. When the input is switched for use, note that the ± terminals are shared.

Item Voltage V

Resistance voltage divider

15/30/60/150/300/600V

Input resistance: Approx. 2 MΩ, Input capacitance:
Approx. 13 pF

Peak voltage of 2.8 kV or rms of 2.0 kV, whichever is less

Peak voltage of 2.0 kV or rms of 1.5 kV, whichever is less

Peak voltage of 1.5 kV or rms of 1.0 kV, whichever is less

600 Vrms (with the output connector protective cover used) CAT II, 400 Vrms (with the output connector protective cover removed) CAT II

With voltage input terminals short and current input terminals open, 50/60 Hz, -80 dB or more (±0.01% of range or less)
Reference value: 50 kHz max., ±{(maximum range rating)/(range rating) × 0.001 × 1% of rng} or less (voltage range, 0.5 A to 20 A current range)
±{(maximum range rating)/(range rating) × 0.0002 × 1% of rng} or less (WT200, 5 mA to 200 mA range)

0.01% or more. The unit of "f" is kHz.
Binding posts
Simultaneous conversion of voltage and current inputs, Resolution: 12 bits, Maximum conversion rate: Approx. 26 µs (at approx. 38 kHz)
Range can be selected manually, automatically, or by communication control.

Range up: When the measured value exceeds 110% of the rated range or the peak value exceeds approximately 300% of the rated range
Range down: When the measured value becomes less than 30% of the rated range and the peak value is less than approximately 300% of the subordinate range

One of the following modes can be set (manually or by communication control): RMS: True RMS measurements for both voltage and current;
V MEAN: Rectified mean calibrated to an RMS sine wave measurement for voltage, and true RMS measurement for current; DC: Mean value measurement for both voltage and current

Floating input

Direct input: 5/10/20/50/100/200 mA (for WT200 only)

0.5/1/2/5/10/20 A (for WT200/WT130)
External input (optional): 2.5/5/10 V or 50/100/200 mV

Direct input: Approx. 6 mΩ + approx. 0.1 µH (0.5 to 20 A, WT200/WT130),Approx. 500 mΩ (5 mA to
200 mA, WT200) External input: 2.5/5/10 V - approx. 100 kΩ or 50/100/200 mV - approx. 20 kΩ

0.5 to 20 A (WT200/WT130): Peak current of 450 A or rms of 300 A, whichever is less
5 to 200 mA (WT200): Peak current of 150 A or rms of 100 A, whichever is less

For external input, the peak value is equal to or less than 10 times range.

0.5 to 20 A (WT200/WT130): Peak current of 150 A or rms of 40 A, whichever is less
5 to 200 mA (WT200): Peak current of 30 A or rms of 20 A, whichever is less

For external input, the peak value is equal to or less than 10 times range.

0.5 to 20 A (WT200/WT130):
Peak current of 100 A or rms of 25 A, whichever is less (WT200)
Peak current of 100 A or rms of 30 A, whichever is less (WT130)
5 to 200 mA (WT200): Peak current of 30 A or rms of 20 A, whichever is less

For external input, the peak value is equal to or less than 5 times range.

Direct input: Large binding posts, External input: Safety terminals

Current A

Shunt input

Measurement Functions

Method
Frequency range
Crest factor

Display accuracy
Accuracy
(within 3 months after calibration)
Conditions:
Temperature: 23 ± 5°C
Humidity: 30 to 75% R.H.
Supply voltage: 100 V ± 5%
Input waveform: Sine wave
Common-mode voltage: 0 V DC
Filter: ON at 200 Hz or less
Scaling: OFF
After CAL is performed, accuracy is
assured by YOKOGAWA calibration
system.
Note: The unit of "f" in accuracy

Effect of power factor

Note: The unit of "f" in accuracy

Effective input range
Accuracy (
Temperature coefficient
Display update rate

Item Voltage/current

DC:
10Hz % f , 45Hz :
45Hz % f % 66Hz :
66Hz , f % 1kHz :
1kHz , f % 10kHz :

10kHz , f % 20kHz

Reference value

20kHz

, f %

50kHz :

expressions is kHz.

expressions is kHz.

within 12 months after calibration

*DC: ±0.2% of range is added if the 0.5/1 A range is selected (WT130 only)

For the input range of 10% to 110%, the above specified accuracy is valid. For the input range of 110% to 130%, the above specified reading accuracy increased by 0.5 times is added to the accuracy.

)

The above specified reading accuracy increased by 0.5 times is added to the accuracy (within 3 months after calibration).
±0.03% of range/°C at 5 to 18°C and 28 to 40°C
4 times/s

± (0.2 % of rdg + 0.2 % of rng)
± (0.3 % of rdg + 0.2 % of rng)
± (0.15 % of rdg + 0.1 % of rng)
± (0.3 % of rdg + 0.2 % of rng)
± (0.2 % of rdg + 0.3 % of rng)
± {(0.05 × )% of rdg}
± (0.5 % of rdg + 0.5 % of rng)
± [{0.15 × (f-10)}% of rdg]

± (0.5 % of rdg + 0.5 % of rng)
± [{0.15 × (f-10)}% of rdg]

Frequency Measurement

Input: One of V1, V2, V3, A1, A2, and A3 is selected.
Operating principle: Reciprocal counting method
Frequency range: 10 Hz to 50 kHz
Accuracy: ±(0.1% of rdg + 1 digit)

Minimum input is more than 30% of rated range.
When an input frequency is less than 200 Hz, FILTER must be ON to obtain the speci-

Minimum input frequency is more than 20% of frequency measurement range.

fied accuracy.

Digital sampling method and summation averaging method

DC, 10 Hz to 50 kHz

*

"3" at rated input

DC:
10Hz % f , 45Hz :
45Hz % f % 66Hz :

66Hz , f % 1kHz :
1kHz , f ^ 10kHz :

10kHz , f % 20kHz :

Reference value

20kHz

, f % 50kHz :

*DC: ±0.2% of range is added if the 0.5/1 A range is selected (WT130 only)
cosϕ = 0
45 Hz % f % 66 Hz: Add ±0.25% of range to display accuracy.
Reference data (50 kHz max.): ±{(0.23 + 0.4 x f)% of rng}
1 > cosϕ > 0
Add the value of the influence of cosϕ = 0 times tanϕ to display accuracy.
Note that ϕ represents the phase angle between voltage and current.

Active power

± (0.3 % of rdg + 0.3 % of rng)
± (0.5 % of rdg + 0.3 % of rng)
± (0.2 % of rdg + 0.1 % of rng)(WT200)
± (0.25 % of rdg + 0.1 % of rng)(WT130)
± (0.5 % of rdg + 0.3 % of rng)
± (0.3 % of rdg + 0.5 % of rng)
± {(0.08 × f)% of rdg}
± (0.8 % of rdg + 0.8 % of rng)
± [{0.19 × (f-10)}% of rdg]

± (0.8 % of rdg + 0.8 % of rng)
± [{0.25 × (f-10)}% of rdg]

Note: "rdg" means reading and "rng" means range.

Communication

Either GP-IB or RS-232-C is selected.
GP-IB
Electrical and mechanical specifications: IEEE Std. 488-1978 (JIS C 1901-1987)
Functional specifications: SH1, AH1, T5, L4, SR1, RL1, PR0, DC1, DT1, C0
Protocol: IEEE Std. 488.2-1987
Code used: ISO (ASCII) code
Address: 0 to 30 talker/listener addresses are settable.
RS-232-C
Transmission mode: Start-stop synchronization
Baud rate: 75, 150, 300, 600, 1200, 2400, 4800, 9600 bps

*

Active power

Apparent power

1-phase
2-wire

1-phase
3-wire

3-phase
3-wire
(two­power­meter
method)

W

Σ W
=W

W

Σ W
=W

(W)

W

i

i=1, 3

1+W3

i

i=1, 3

1+W3

(VA)

VA=V× A

VAi=Vi× A

i=1, 3

Σ VA
=VA

+VA

1

VA

i=Vi

i=1, 3

Σ VA

3

=

×

2

× A

(VA1+VA3)

3-phase

W

Computation

3-wire

i=1, 2, 3

(three-

(Note that W

power-

does not have

meter

physical

method)

meaning.)

Σ W
=W

3-phase

W

4-wire

i=1, 2, 3

Σ W

=W

Computing

Depends on

range

selected V
and A ranges.

Display
resolution

Computing
accuracy
(relative to the
value calculated
from measured
values)

Note 1:The apparent power (VA), reactive power (var), power factor (PF), and phase angle

(deg) measurements in this instrument are computed digitally from the voltage, cur­rent, and active power. If the input is non-sinusoidal, the measured values may differ
from those obtained with instruments employing different measurement principles.

Note 2:When the current or voltage is less than 0.5% of the range, VA and var will be dis-

played as 0, and PF/deg will be displayed as an error.

Note 3:The Lead and Lag are displayed for V and A input at 50% or more of the rated range.

The detected lead/lag accuracy is ±5 degrees over the frequency range of 20 Hz to 2
kHz.

Note 4:In a Σvar calculation, the var value of each phase is calculated as a negatively signed

value when the phase of the current input is advanced with respect to the voltage
input, and is calculated as a positively signed value when the phase is lagging.

* The WT200 can provide 5-digit display (note that the resolution is 20000).

VAi=Vi× A

i

2

i=1, 2, 3

Σ VA

3

=

×

3

(VA1+VA2 +VA3)

1+W3

VAi=Vi× A

i

i=1, 2, 3

Σ VA

1+W2

=VA

+VA

1

+W

3

+VA

Depends on
selected V and
A ranges.

9999* 9999* 9999*

±0.005% of VA
range

—

Reactive

(var)

(VA)2–W

var

i

i

= (VAi)2–W

i=1, 3

Σ var

3

=var

+var

1

var

i

i

= (VAi)2–W

i=1, 3

Σ var
=var

1

var

i

i

= (VAi)2–W

i=1, 2, 3

Σ var
=var

+var

1

var

i

i

= (VAi)2× W

i=1, 2, 3

Σ var

2

3

=var

+var2+var

1

Same as apparent
power (var ^ 0)

±0.005% of var range

+var

3

3

3

2

2

i

2

i

2

i

2

i

3

i=1, 2, 3

Power factor

(PF)

W

VA

PF

i

W

i

=

VA

i

i=1, 3

Σ PF

Σ W

=

Σ VA

PF

i

W

i

=

VA

i

i=1, 3

Σ PF

Σ W

=

Σ VA

PF

i

W

i

=

VA

i

Σ PF

Σ W

=

Σ VA

PF

i

W

i

=

VA

i

i=1, 2, 3

Σ PF

Σ W

=

Σ VA

–1 to 0 to 1

± 1.000*

0.0005

Phase angle

(deg)

W

–1

()

cos

VA

ϕ

i

W

i

=cos–1()

VA

i

i=1, 3

Σϕ

Σ W

–1

=cos

()

ΣVA

ϕ

i

W

i

=cos–1()

VA

i

i=1, 3

Σϕ

Σ W

–1

=cos

()

ΣVA

ϕ

i

W

i

=cos–1()

VA

i

i=1, 2, 3

Σϕ

Σ W

–1

=cos

()

ΣVA

ϕ

i

W

i

=cos–1()

VA

i

i=1, 2, 3

Σϕ

Σ W

–1

=cos

()

ΣVA

–180 to 0 to 180

± 180.0

Resolution
(power factor
±0.0005)

Display Function

Display type: 7-segment LED
Number of displays: 3

Display

A

V, A, W, VA, var (each element), elapsed integrating time

B

V, A, W, PF, deg (each element), % (contents ratio in %, THD)

C

V, A, W, V · AHz, ±Wh, ±Ah (each element), Vpk, Apk, MATH

Displayed value

* In the WT200 either 4 or 5 digits for display can be selected.

Unit: m, k, M, V, A, W, VA, var, Hz, h±, deg, %
Display update rate: 4 times/s
Response time: Approx. 0.5 s (time for displayed value to settle within specified

Display scaling function

Significant digits: Selected automatically according to significant digits in the voltage

Setting range: 0.001 to 9999 (WT200), 0.001 to 1000 (WT130)

Averaging function:

Either of the following two algorithms can be selected:
Exponential averaging
Moving averaging
Response can be set; for exponential averaging, the attenuation constant can be selected
and for moving averaging, the number of averages (N) can be set to 8, 16, 32, or 64.

Peak over-range display

The alarm LED will light up if the rms value is greater than 140% of the range or the
peak value is greater than 300% of the range.

MAX hold function (WT200 only)

Capable of storing the maximum values for V, A, W, VA, var, Vpk, and Apk.

accuracy of final value after step change from 0% to 10% or 100%
to 0% of rated range)

and current ranges

Maximum Reading

V, A, W: 9999
Wh, Ah: 999999
V, AHz : 9999

MATH function

Method: When the DISPLAY C function is set to MATH, the efficiency

(WT130 only) and input crest factor can be measured, and the
results of four arithmetic operations of measured values can be
displayed on Displays A and B as well as the average active power
after time-conversion of integrating power (WT200 only).

Integrator Function

Display resolution: Depending on integrated value, the resolution will be changed (for

Maximum display: –99999 to 999999 MWh/MAh
Modes: Standard integration mode (timer mode)

Timer: When the timer is set, integration will be stopped automatically.

Type: Standard type Adds active power and current value of normal

Count overflow: If the integration count exceeds 999999 MWh/MAh or -999999

Accuracy: ± (display accuracy + 0.2% of rdg)
Timer accuracy: ±0.02%
Remote control: Start, stop, and reset can be remotely controlled by an external

WT200).
Depending on elapsed time value, the resolution will be changed
(for WT130).

Continuous integration mode (repeat mode)
Manual integration mode

Setting range: 000 h:00 min:00 sec to 10000 h:00 min:00 sec
(WT200)
Setting range: 000 h:00 min to 999 h:59 min (WT130)
(When set time is 0, the manual integration mode is automatically
selected.)

measurements.
Advanced type (WT200 only) Integrates active power and current
values in short time intervals, not depending on input signal pe­riod.

MWh/MAh, integration stops and the elapsed time is held on the
display.

contact signal. Note that this is available only when the /DA4 or /
DA12 option has been installed.

Internal Memory Function

Measurement data Number of data that can be stored: WT200 (253421): 600 blocks

Writing interval: 250 ms, or 1 s to 99 h:59 min:59 sec
Reading interval: 250 ms, or 1 s to 1 h (both intervals can be set in

Panel setup information: Four-pattern information can be written/read.

units of second)

WT130 (253502): 300 blocks
WT130 (253503): 200 blocks

D/A Converter (Optional)

Output voltage: ±5 V DC FS (approx. ±7.5 V maximum) at rated value or range
Number of output channels

Output data selection: Can be selected for each channel.
Accuracy: ± (display accuracy + 0.2% of range)
Update rate: Same as display update rate
Temperature coefficient: ±0.05% of f.s./°C
Output format

Frequency

Integration

Other items

: 12 when the /DA12 option is installed; 4 when the /DA4 option is

installed

D/A output

7.5V

5.0V

2.5V

0.5V

0

D/A output

7.0V

5.0V

0

Displayed value

140%

100%

0%
–100%
–140%

For PF and deg, a
value between ±5 and
±7 V will not be
output. If an error
occurs, the output will
be approx. 7.5 V.

10Hz 100Hz 1kHz 10kHz

140% input of the rated value

t0: Rated value setting time

Output

7.0V

5.0V
0V

–5.0V
–7.0V

–100%–140%

Rated value input

D/A output

7.5V

7.0V

5.0V

0V

–5.0V
–7.0V

–7.5V

Displayed value50kHz

t0 Integration time

Displayed value

140%100%