47
5 Planning the installation
Planning the device communication and plant monitoring
5.6.3 Communication cable requirements
Cable type
Shielded and twisted pair cable
(CAT5 or CAT6)
Cable diameter
7.2 mm
Wire cross-section
0.25 ... 1.5 mm
2
Table 5.5.:
Specification of the communication cable
The communication cable is required for connection to the follow-
ing units:
●
Data logger
●
External alarm unit
●
Ripple control receiver
● External power-off
Lay the communication cable with a suitable clearance to the AC
and DC cables to prevent interference in the data connection.
5.6.4 Cable gland for the communication con-
nection
The inverter has 1 cable gland for 2 communication cables.
5.6.5 Connection of a data logger via RS485
The inverter can be connected to a data logger via RS485, e.g.
for monitoring the PV system or changing the inverter settings.
The SUNSPEC protocol with Modbus RTU is used for data trans-
mission.
Multiple inverters can be connected in series to a data logger.
The following recommendations must be complied with to ensure
a stable data connection.
Connecting a single inverter to a data logger
►
Switch on the RS485 termination resistor.
►
Lay the communication cable with a suitable clearance to
the AC and DC cables to prevent interference in the data
connection.
Connecting multiple inverters to a data logger
►
If the data logger is located at one end of the RS485 chain,
then switch on the RS485 termination resistor of the data
logger and of the last inverter in the RS485 chain.
►
If the data logger is
not
located at either end of the RS485
chain, switch on the RS485 termination resistor at the two
inverters at the ends of the RS485 chain.
► Switch off the RS485 termination resistor at all other invert
-
ers (standard setting).
► A different inverter ID must be set at each inverter. Other
-
wise the data logger cannot identify the individual inverters.
►
Set the same RS485 baud rate at all inverters (standard:
19200).
►
Lay the cable with a suitable clearance to the AC and DC
cables to prevent interference in the data connection.
Installation and Operation Manual for Solar Power Inverter M70A EU V2.0 EN 2020-08-03
