Specifications

Section 3: Installation Planning
3-11
3.6 S-NET
S-Net is an RS-485 serial network for communication between the ACU and node devices.
Typically, the cable used is two twisted-pairs with an overall shield; one pair is for data, the other
pair is for DC power. It is recommended that separate data and power cables be used when the
length exceeds 500 feet (150 meters). Table 3-3 lists recommended cable.
Table 3-3: S-Net Cable Recommendations
Ty p e Descr iption Gauge
S-Net Length < 500 Feet
Data and Power
Belden 9552
Belden 1069
2-Pair
18 AWG
16 AWG
S-Net Length > 500 Feet
Data Only
Belden 9841 1-Pair 24 AWG
S-Net Length > 500 Feet
Power Only
Belden 9341
Belden 9342
Belden 9343
2-Conductor
18 AWG
16 AWG
14 AWG
3.6.1 CABLE LOSSES
Power loss over distance will effect the performance of network devices. The length of the S-
Net can be up to 4000. To power a 200mA reader at this distance requires a wire gauge of 16
AWG or larger. For a single run, this allows 16VDC at the node if 24 VDC is the source.
Table 3-4: S-Net Typical Wire Loss (18 AWG)
Device
Minimum Voltage
Required
Po wer Required
S-Net IR
Drop/1000 Ft
DR 4204 16 VDC 1.96 Watts 0.84 Volts
DR 4205 16 VDC 1.96 Watts 0.84 Volts
DR 4208 16 VDC 4.8 Watts 2.4 Volts
DR 4226 16 VDC 9.6 Watts 4.8 Volts
DR 4238 16 VDC 12 Watts 6 Volts
VIP2 16 VDC 0.98 Watts 0.42 Volts