When the voltage exceeds 30 Vdc,
an additional resistor is required.
The permitted operational areas are
shown in figure 9.
Operational area 1 represents the area of
operation without the need of an external
loop resistance.
Operational area 2 shows the area where
a resistance is required.
The power rating of the external resistor
depends on the value of the resistor.
We recommend 1 W / kΩ
Figure 9 Selecting the external loop resistor
Optional RS communication connections
For the cable connections of the mains and the alarm contacts, refer to previous section.
Caution
Keep the RS-232C / RS-485 lines as short as possible.
RS-232C : Cable requirements: maximum length 15 metres (50 ft); twisted and shielded.
RS-485 : Cable requirements: maximum length 1200 metres (3900 ft); twisted and shielded.
Figure 10 RS-232C / Rs-485 connections
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