Instruction Manual

The equations for calculating SNR are:
SNR = 20 × log (Vs/Vn) where Vs is the signal voltage and Vn is the noise voltage;
SNR = 20 × log (As/An) where As is the signal amplitude and An is the noise amplitude; or
SNR = 10 × log (Ps/Pn) where Ps is the signal power and Pn is the noise power.
single-point
ground
All grounds within a system are made to a single ground to avoid creating ground loops.
site survey Conducting a site survey, also known as a radio signal strength indication (RSSI), analyzes the radio
communications link between the Gateway (or master radio) and any Node (or slave radio) within the
network by analyzing the radio signal strength of received data packets and reporting the number of
missed packets that required a retry.
slave ID The slave ID is an identifying number used for devices within a Modbus system. When using more than
one Modbus slave, assign each slave a unique ID number.
By default, Gateways are set to Modbus Slave ID 1.
sleep mode During normal operation, the Sure Cross radio devices enter sleep mode after 15 minutes of operation.
The radio continues to function, but the LCD goes blank. To wake the device, press any button.
slow scan mode (All internal battery models)In slow scan mode, the radio wakes up every 15 minutes to search for its
parent radio. If a parent or master radio is not found, the radio goes back to sleep for another 15
minutes.
SMA connector An SMA connector (SubMiniature version A) is a 50 ohm impedance connector used for coaxial RF
connections and developed in the 1960s. An SMA connector is typically used between the radio and the
antenna.
spread
spectrum
Spread spectrum is a technique in which the transmitter sends (or spreads) a signal over a wide range of
frequencies. The receiver then concentrates the frequencies to recover the information. The Sure Cross
radio devices use a version of spread spectrum technology called Frequency Hop Spread Spectrum.
star networks A star topology network is a point to multipoint network that places the network master radio in a center
or hub position. Slave radios only transmit messages to the master radio, not to each other. These
network layouts can be very flexible and typically operate relatively quickly. Slave radios acknowledge
receipt of messages transmitted from the master radio.
For more information on Banner's star network products, refer to the Sure Cross Performance DX80
Wireless I/O Network Instruction Manual (p/n 132607)
switch power Efficient power management technology enables some Flex Power devices to include an internal power
output supply, called switch power (SP), that briefly steps up to power sensors (ideally, 4 to 20 mA loop-
powered sensors). The warmup time denotes how long the sensor must be powered before a reliable
reading can be taken. After the warmup time has passed, the input reads the sensor, then the switched
power shuts off to prolong battery life.
system
operating
margin (fade
margin)
The system operating margin, or fade margin, is the difference between the received signal level (in
dBm) and the receiver sensitivity (also in dBm) required for reliable reception. It is recommended that
the receiver sensitivity be more than 10 dBm less than the received signal level. For example, if the
signal is about –65 dB after traveling through the air and the radio receiver is rated for -85 dB, the
operating margin is 20 dB — an excellent margin.
Sure Cross
®
Performance DX80 Wireless I/O Networks
66 www.bannerengineering.com - Tel: + 1 888 373 6767