IQ SMARTSENSOR 105 - Manual (Page 35)

SmartSensor 105 User Guide – Wavetronix LLC 9/20/07
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35
Appendix G – Cable Lengths
The following recommendations allow the user to provide reliable power to the
SmartSensor. The SmartSensor cable’s red and black wires provide a 20 AWG wire pair.
The other pairs on the SmartSensor cable are 22 AWG and are normally used for
communication.
Gauge Pairs 24 V 12 V
20 AWG 1-Pair 600 ft 110 ft
Additional 22 AWG Each Pair Add 400 ft Add 75 ft
22 AWG 1st Pair 400 ft 75 ft
Additional 22 AWG Each Pair Add 400 ft Add 75 ft
14 AWG 1-Pair 2500 ft 450 ft
12 AWG 1-Pair 3900 ft 700 ft
10 AWG 1-Pair 6000 ft 1050 ft
8 AWG 1-Pair 9900 ft 1750 ft
6 AWG 1-Pair 14,000 ft 2500 ft
Alternate Power Cables
Power Cable
SmartSensor Cable
Old SmartSensor Cable
Table 8 - Maximum Cable Length for Power (ft)
If the cable length is longer than 600 feet when operating at 24 V, it is possible to
increase the maximum cable length by wiring a pair of lines normally used for RS-232
communications with the red and black wires.
If the cable length is 200 feet or greater you cannot reliably use RS-232 communications.
To add 400 feet and achieve a maximum cable length of 1000 feet, connect the orange
wire (normally RTS) to the red wire and the brown wire (normally CTS) to the black
wire.
If your cable run is longer than 1000 feet, it is possible to sacrifice additional
communication pairs to increase the maximum cable length for power. However, you
may desire to communicate to the sensor over two independent channels, in which case
you will need to consider an alternate cable for power. The AWG for wire pairs that
achieve a 2000 ft maximum cable length or greater at 12 and 24 V are listed in Table 8.
To achieve reliable wired communications, the selected baud rate must be compatible
with the length of the cable run. The table below shows the cable length
recommendations for wired communications (see Table 9):
115.2 57.6 38.4 19.2 9.6
RS-485 300 ft 600 ft 800 ft 1000 ft 2000 ft
RS-232 40 ft 60 ft 100 ft 140 ft 200 ft
Baud Rate (Kbps)
Table 9 - Maximum Cable Length for Wired Communications (ft)
To provide two independent communication channels with a homerun cable length over
200 ft, convert the RS-232 data into RS-485 using a Click! 304 in a pole-mount cabinet