![Bender ISOMETER isoLR275 Скачать руководство пользователя страница 56](http://html.mh-extra.com/html/bender/isometer-isolr275/isometer-isolr275_manual_2731668056.webp)
56
isoLR275_D00127_00_M_XXEN/07.2018
6. Serial interface
6.1
RS-485 interface with BMS protocol
The RS-485 interface electrically isolated from the device electronics and the
current output serves as a physical transmission medium for the BMS proto-
col. If several isoLR275 or other bus-capable devices are interconnected in a
network via the BMS bus, the BMS bus must be terminated at both ends with
a 120 Ω resistor.
An RS-485 network that is not terminated, is likely to get instable and may re-
sult in malfunctions. Only the first and the last device in one line may be ter-
minated. Devices in between must not be terminated with 120 Ω. Hence, stub
feeders in the network must not be terminated. The length of the stub feeders
is restricted to 1 meter.
A
B
A
B
A
B
1st device
... device
last device
120
W
0.4 W
120
W
0.4 W
Stub feeder
maximum 1 m
Maximum length of the RS485 bus: 1200 m