Panasonic KW8M - For Output Connection; RS485 Communication

KW8M Eco-POWER METER
10
3.4 For Output connection
・Since the transistor output is insulated from the internal circuit by a photo-coupler, it can be used both
as a NPN output and PNP (equal value) output.
3.5 RS485 Communication
・When using shielded cable for the RS485 transmission line, ground one end.
Use a class D dedicated earth for grounding. Do not share a ground with other earth lines. (Fig.1)
・Be sure to connect with daisy chain the RS485 transmission line between each unit.
Do not use a splitter. (Fig.2)
・With a terminal station, RS485 (E) (No.10) and RS485 (-) (No.9) should be shorted.
*E terminal is not SG (signal ground) terminal. Do not ground shielded cable.
(Fig.2)
Correct wiring
○
Incorrect wiring
×
Terminal Terminal
station station
(＋) (＋)
Shielded cable
To RS485 device
Shielded cable
Eco-POWER METER
General station
Eco-POWER METER
Terminal station
Class D grounding
Class D grounding
(－
)
(
E
) (－
)
(
E
)
Shorted
(Fig.1)
Eco-POWER
METER
(＋)
(
－
)
Eco-POWER
METER
Auto transformer
(Fig.B) No Good example
Do not ground the secondary side.
Do not use an auto-transformer.
Operating power supply
Measured voltage input
Operating power supply
Measured voltage input
Insulated
transformer
Input equipment
(sensor etc.)
Input equipment
(sensor etc.)
(＋)
(
－
)
Power supply for Load
- +
NPN output
Eco-POWER METER
Pulse (－)
Pulse (+)
PNP output
6
- +
Eco-POWER METER
Power supply for Load
7
Pulse (－)
Pulse (+)
6
7
Load Load