0BPreparation
2-28
Preparation
Preparation
[CTD8E (CT expansion)]
[CTD8E (CT expansion)]
When connecting dedicated CT, perform wiring as follows: between terminals [9] and [10], [11]
and [12], [13] and [14], [15] and [16], [17] and [18], [19] and [20], [21] and [22], and [23] and [24]
in single-phase 2-wire; phase R between terminals [9] and [10], [13] and [14], [17] and [18], and
[21] and [22], and phase T between terminals [11] and [12], [15] and [16], [19] and [20], and [23]
and [24] in single-phase 3-wire or 3-phase 3-wire; phase R between terminals [13] and [14] and
[21] and [22], phase S between terminals [15] and [16] and [23] and [24], and phase T between
terminals [17] and [18] and [9] and [10] in 3-phase 4-wire.
When connecting dedicated CT, perform wiring as follows: between terminals [9] and [10], [11]
and [12], [13] and [14], [15] and [16], [17] and [18], [19] and [20], [21] and [22], and [23] and [24]
in single-phase 2-wire; phase R between terminals [9] and [10], [13] and [14], [17] and [18], and
[21] and [22], and phase T between terminals [11] and [12], [15] and [16], [19] and [20], and [23]
and [24] in single-phase 3-wire or 3-phase 3-wire; phase R between terminals [13] and [14] and
[21] and [22], phase S between terminals [15] and [16] and [23] and [24], and phase T between
terminals [17] and [18] and [9] and [10] in 3-phase 4-wire.
In this case, terminals [9], [10], [13], [15], [17], [19], [21], and [23] are specified as S, and
terminals [10], [12], [14], [16], [18], [20], [22] and [24] as L.
In this case, terminals [9], [10], [13], [15], [17], [19], [21], and [23] are specified as S, and
terminals [10], [12], [14], [16], [18], [20], [22] and [24] as L.
Single
phase
2-wire
Single
phase
2-wire
Single
phase
3-wire
Single
phase
3-wire
3-phase
3-wire
3-phase
3-wire
3-phase
4-wire
3-phase
4-wire
CT1([13]-[14]) L
R
R
R
CT2([15]-[16]) L
T
T
S
CT3([17]-[18]) L
R
R
T
CT4([19]-[20]) L
T
T
-
CT5([21]-[22]) L
R
R
R
CT6([23]-[24]) L
T
T
S
CT7([9]-[10]) L R R T
CT8([11]-[12]) L
T
T
-
Number of
measurement
circuits
8 circuits
4 circuits
4 circuits
2 circuits
*1
Do not touch charging metal part of the dedicated CT terminal. Electric shocks may occur.
*2
Do not ground the dedicated CT. Doing so causes a failure.
*3
When measuring electric power containing higher harmonics, such as inverter primary current,
select a dedicated CT having allowance to standard load. For the current waveform (effective
value of 2 A, and peak value of 8 A) as shown below, a dedicated CT of 50 A must be used. If
5ACT is used, saturation occurs, preventing obtaining correct measurement values.
In general, entering a filter, AC reactor, etc., between the power supply and an inverter greatly
changes the ratio of current and effective value of the inverter primary current. The ratio also
changes depending on the capacitor, diode, etc.
Example of inverter primary current waveform
●
RS-485 communication
PMU1A
(Electric
power)
PMU2A
(Power
two-system)
EMU8A
(Pulse/temperature)
CTD8E
(CT
expansion)
○
○
○
×
O: With terminal
X: Without terminal
When using RS-485 communication functions, connect a communication cable between
terminals [8] and [7].
A termination resistor must be connected to each end
of the transmission path. Each termination resistor
should be 120
Ω
(1/2 W).
Communication connection diagram
x
For the connection configuration, 1 : 1 or 1 : N is applicable. The number of connected units
is as follows: when the protocol is CompoWay/F, 31 units, and when Modbus, up to 99 units.
The total cable length is up to a maximum of 500 m. For the cable, use a twisted pair cable
with shield (AWG24 (cross-sectional area of 0.205 mm2) to AWG14 (cross-sectional area of
2.081 mm2).
*
Do not ground the RS-485 signal line. Doing so causes a failure.
*
Do not carry out RS-485 communication during USB communication. (Doing so may
return a response.)
形 KM1
RS-485
B
(+)
A
(-)
8
7
Current peak value of 8 A
Current effective value of 2 A
Model KM1
