User manual

NurseCall Main Unit Description | en 23
TeleAlarm SA® User Manual 953.92 | v1.0 | 2007.07
4.2.6 RS-485 interface
One NurseCall Main Unit and up to 32 NurseCall Relay Units can be connected to a RS485-bus.
The bus must be connected to pins 2 and 5 of the units.
X For connector wiring, see Section 13.7.4 RS-485 (unit rear), page 87.
In this configuration, you always should connect the NurseCall Main Unit first. The NurseCall
Relay Units must then be connected to the RS485-bus one by one (not at the same time).
You can add a Printer Interface to the RS485-bus in order to connect an additional printer or a
giant display. In such configuration, the in-house paging system can be combined with a
printer without a PC.
Relay output
In the same connector, a potential free contact is available. It is a low current switching
contact. The relay (potential free, switching power max. 48 V / 0.5 A) is activated at a Call for
Help, Call for Assistance or Fire Call. This relay can be set as closing or switching contact (cycle
of 10 seconds on / 10 seconds off). This feature can be used to drive a signal lamp for
example.
X For connector wiring, see Section 13.7.4 RS-485 (unit rear), page 87.
X For relay setting, see Section 7.3.8 Output relay setting, page 50.
4.2.7 Antenna
The antenna is connected to the NurseCall Main Unit using the adapter supplied with the unit.
X See Section 6.2.4 Installing the antenna, page 29.
CAUTION!
Keep polarity equal when connecting further units to the RS485 bus!
CAUTION!
Maximum RS485-bus length: 1200 m.
X Use only one twisted pair cable for the interconnection.
i
NOTICE!
The Receiver Units located at the two ends of the bus should be terminated with a 100 Ohm
resistor.
X See Section 6.2.8 Connecting the RS-485, page 33 for more information about the jumper
setting.