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Installation
3.6.2 RS-485 Connection
The pin definition for the RS-485 terminal block is shown in Table 3-3.
- Pins 1 and 2 provide a 12VDC bus for use with accessories.
(If use of the 12VDC bus is necessary, please set switch 1 to the ON position.)
- Pins 3 and 5 are both connected to the DATA+ input.
- Pins 4 and 6 are both connected to the DATA - input.
These connections allow easy daisy-chaining of multiple inverters.
A 120ohm bus termination resistor and associated control switch are located
on the communication board. The switch function is as shown in Table 3-4.
Different RS-485 connection scenarios require different set up for the 120ohm
bus termination resistor.
• When multiple inverters are cascaded (i.e., "daisy-chained"), only the last inverter
in the chain must have its bus termination resistor switched ON.(Figure 3-19)
• If the length of any RS-485 bus is greater than 610m, it is recommended to use
Belden 3105A cable (or equivalent cable) to ensure communication quality.
• The length of RS-485 cable is recommended to be less than 30m in general.
- It is recommended to use twisted-pair as a communication cable for well
transmission quality.
Pin
1
2
3
4
5
6
ATTENTION
Table 3-3: RS-485 Terminal block wiring
Function
VCC (+12V)
GND
DATA+
DATA-
DATA+
DATA-
1 2 3 4 5 6
VCC GND D+
D-
34
D+
D-
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