4.2 Wiring Diagrams
Single-phase 2-wire
A-
K
L
1
N
VT
-
-
+
+
-
+
B+ SG D2 D2 D1 D1 N1 L1 PE
P1 P2
1S 1L
K
L
Dedicated
CT
RS-485
Fuse
Signal
ground
Power
supply
Pulse
output-2
of electric
energy
Pulse
output-1
of electric
energy
Load
Established
instruments
Established
CT
Power
supply
Single-phase 3-wire
A-
K
L
1
N
2
VT
K
L
-
-
+
+
-
+
B+ SG D2 D2 D1 D1 N1 L1 PE
P1 P0 P2
1S 1L
2S 2L
K
L
K
L
Dedicated
CT
Power
supply
RS-485
Fuse
Signal
ground
Power
supply
Pulse
output-1
of electric
energy
Pulse
output-2
of electric
energy
Load
Established
instruments
Dedicated
CT
Established
CT
Established
CT
Three-phase 3-wire
A-
K
L
1
2
3
VT
K
L
-
-
+
+
-
+
B+ SG D2 D2 D1 D1 N1 L1 PE
P1 P2 P3
1S 1L
3S 3L
R
S
T
K
L
K
L
Dedicated
CT
Power
supply
RS-485 Signal
ground
Power
supply
Pulse
output-1
of electric
energy
Pulse
output-2
of electric
energy
Load
Established
instruments
Dedicated
CT
Established
CT
Fuse
Established
CT
Three-phase 4-wire
A-
K
L
1
R
S
T
N
2
3
N
VT
K
L
K
L
K
L
K
L
K
L
-
-
+
+
-
+
B+ SG D2 D2 D1 D1 N1 L1 PE
P1 P2 P3 P0 1S 1L 2S 2L 3S 3L
Dedicated
CT
RS-485 Signal
ground
Power
supply
Pulse
output-1
of electric
energy
Pulse
output-2
of electric
energy
Load
Established
instruments
Established CT
Established CT
Fuse
Dedicated
CT
Dedicated
CT
Established CT
Power
supply
NOTE
●
Be sure to use the dedicated CT for the UPM101.
●
When connecting the secondary-side cable of the dedicated CT to the UPM101,
the cable should be twisted.
●
If extending the secondary-side cable of the dedicated CT, use two-core twisted-
pair cable.
4.3 Connections for RS-485 Communication
(FG)
Approximately 1.2 km maximum length (up to 31 units)
Ethernet
RS-485
Ethernet
/
RS-485
Converter
(A-) (B+) (SG)
(A-) (B+) (SG)
(A-) (B+) (SG)
(A-) (B+) (SG)
RS-485
RS-485
UPM101
UPM101
UPM101
Terminator
PC
CAUTION
●
RS-485 communication with the UPM101 is based on a 2-wire system.
Note the following:
(1) The SG terminal (SG) is connected to match the signal level of the RS-485
communication line. Connect the SG terminal without grounding it.
(2) Connect all shield lines (FG) to provide noise protection on the RS-485
communication line, and ground them in one location.
(3) When using shielded twisted-pair cable, use the shield line as FG without
connecting the SG terminal.
IM 77C01J01-00EN
3
