ABB IM300-I Operational Manual page 11

2.2.4.
Communication wiring

Straight-line Wiring Method:
Note: The straight-line wiring method should consider impedance matching
resistor is about 100 ~ 120Ω.
2.2.5. Digital input wiring
IM300 monitors the number of switches / digital inputs entered by 4 dry
nodes, the use of optical isolation input, isolation voltage 1500VDC, The 24VDC
isolated from the internal output of the device provides input circuit power for the
dry node. Wiring is shown in fig. 2-2-4.
IM300 Intelligent Power Monitoring Instrument
Fig 2.2.3.5 3P3W+1CT
Fig. 2-2-3-6 RS485 straight-line wiring method
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