Kaco Powador 2002 Operating Manual page 30

Installing the inverter
Authorised electrician
Properties of the RS485 data line
Maximum length of the RS485
bus line
Maximum number of
connected bus devices
Data line
NOTE
Diff erent manufacturers do not always interpret the standard on which the RS485 protocol is based
in the same way. Note that the wire designations (- and +) for wires A and B can vary between manu-
facturers.
NOTE
Calculating effi ciency by measuring the current and voltage values leads to unusable results due to
the tolerances of the measurement devices. The sole purpose of these measured values is to monitor
the basic operation of the system.
Connecting the RS485 bus
 To prevent interference during data transmission:
• Observe the wire pairing when connecting DATA+ and DATA- (see Figure
27)
• Do not install RS485 bus lines in the vicinity of live DC/AC cables.
1. Unscrew the cable fi tting.
2. Thread the connection cables through the cable fi tting.
3. Connect the connection cables to the corresponding connection termi-
nals (see Figure 25 on page 28).
4. The following must be connected to all inverters and to the data monitor
unit in the same way:
– Wire A (-) with wire A (-) and
– Wire B (+) with wire B (+) (see Figure 26 on page 29)
5. Tighten the cable fi tting.
6. Activate the terminating resistor on the terminal unit.
NOTE
When using the RS485 bus system, assign a unique address to every bus device (inverter, sensor) and
terminate the terminal units (see the "Settings" 8.3 on page 36 menu) .
Page 30
The maximum allowed length of the RS485 bus is 1200 m.
This length can be reached only under optimum conditions.
Lengths exceeding 500m generally require a repeater or a hub.
31 inverters + 1 data monitoring unit
Twisted, shielded. Recommendations:
LI2YCYv (twisted pair) black for laying cable outside and in the ground, 2 x 2 x 0.5
LI2YCY (twisted pair) grey for dry and moist indoor spaces, 2 x 2 x 0.5
Figure 27: RS485 bus: Assignment
of twisted-pair wires
Operating Instructions for Powador 2002-6002_EN