The pin definition for the RS-485 terminal block is shown in
Table 3-1.
- Pins 1 and 2 provide a 12VDC/0.5A bus for use with accessories such as R3
Power Monitor.
*
To avoid nuisance trip of rapid shutdown system (RSS), if 12V AUX power
is used to power on transmitter of RSS with AC interlock purpose, do not
connect additional load on 12V AUX power.
- 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 (See Figure 3-37) The switch function is as shown
in
Table 3-2
.
Different RS-485 connection scenarios require different set up for the 120ohm
bus termination resistor.
•
When several inverters are cascaded (i.e., "daisy-chained") only the last inverter
in the chain must have its bus termination resistor switched ON. Refer to
Figure 3-37.
•
If the length of any RS-485 bus is greater than 2000' (610m), the use of Belden
3105A cable (or eq.) is recommended to insure communication quality.
(When using R3 Monitor, a 4-wire cable is required; Belden 3108A (or eq.) is
recommended.)
3.5.2 RS-485 Connection
Pin Function
1 VCC (+12V)
2 GND
3 DATA+
4 DATA-
5 DATA+
6 DATA-
Table 3-1: RS-485 Terminal block wiring
1 2 3 4 5 6
In order to have good transfer quality, twisted-pair wire is recommended to be
used as communication cable.
ATTENTION
59
Installation
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