Table 4: SA Bus Rules
Rules/Limits
Category
Each bus supervisor supports one SAB.
General
An SAB supports up to 10 devices.
Note:
The SAB supervisor provides power for the NS network sensors on the bus. Due to
power limitations,
only 4
of the 10 devices on an SAB can be NS sensors.
Note:
The SAB on NIE29 models that have an integral Local Controller Display do not support
an optional DIS1710 Local Controller Display.
SABs do not support repeaters.
Number of Devices
Supported on the Bus
365 m (1,198 ft) maximum bus length
152 m (500 ft) maximum between an NS network sensor and the bus supervisor FEC or VAV
Modular Assembly (VMA) supplying power to the sensor) using bus cable connected to the SAB
screw terminal blocks
30 m (98 ft) maximum length for network sensors using bus cables connected to the 6-pin
modular jack (6-Pin SAB port)
366 m (1,198 ft) maximum bus length
1.5 m (5 ft) maximum between NIE and DIS1710 Local Controller Display
SAB Cable Length
Screw Terminal Connections
: 0.6 mm (22 AWG) Stranded 4-wire, 2-wire twisted pair, Shielded
Cable for screw terminals
Modular Jack Connections
: 6-Pin Modular Connectors with 24 or 26 AWG 6-wire, 3-wire twisted
pair
Recommended Bus Cable
Type
Each SAB supervisor has integral (fixed ON) EOL termination, which typically provides sufficient
EOL termination on an SAB. Long SAB runs or persistent communication problems on an SAB
may require EOL termination at the last device on the SAB (in addition to the integral EOL
termination at the SAB supervisor). All NIE29 models are SAB supervisors.
EOL Termination on the SAB
1
If third-party devices are connected to the bus, the cable lengths should be reduced (if necessary) to match the third-party
vendor recommendations. Also, use only one type of connection, either Screw Terminal or Modular Jack, but not a combination
of both.
Table 5: Rules for M-Bus Protocol
Rules/Maximums Allowed
Category
One direct M-Bus serial (RS-232) connection to the RS232C port is supported.
Connection requires an RS232-to-M-Bus Level Converter on the RS232C port.
FC port does not support M-Bus integration.
No restrictions in topology, but bus topology is strongly recommended
General
Depends on level converter (logical maximum is 250 devices).
Number of Devices
16
NIE29 Installation Instructions
