local and non-
local registers
Local registers are registers specific to the device in question. When discussing a Gateway, the
Gateway's local registers include the registers specific to the Gateway in addition to all the Nodes'
registers that are stored in the Gateway. Non-local, or remote, registers refer to registers on other
Modbus slave devices, such as other MultiHop slave radios or third-party Modbus devices.
master/slave
relationship
The master/slave relationships is the model for a communication protocol between devices or processes
in which one device initiates commands (master) and other devices respond (slave). The Sure Cross
network is a master/slave network with the Gateway acting as the master device to the Nodes, which
are the slave devices. A PC can also be a master device to a wireless sensor network. See
star
networks
.
maximum bad
count
The maximum bad count refers to a user-established maximum count of consecutive failed polling
attempts before the Gateway considers the radio (RF) link to have failed.
maximum
misses
The maximum misses is the number of consecutive polling messages the Node fails to respond to. For
more information, see Polling Rate and Maximum Misses.
median filter
When the median filter is turned on, three samples are taken for each analog sensor reading. The high
and low values are discarded and the middle value is used as the analog value. Set to zero (0) to turn
off the median filter. Set to one (1) to turn on the median filter.
Modbus
Modbus is a master-slave communications protocol typically used for industrial applications.
Modbus/TCP
Modbus/TCP is an open standard protocol very similar to Modbus RTU except that it uses standard
Internet communication protocols.
MultiHop
MultiHop networks are made up of one master radio and many repeater and slave radios. The MultiHop
networks are self-forming and self-healing networks constructed around a parent-child communication
relationship. A MultiHop Radio is either a master radio, a repeater radio, or a slave radio.
The master radio controls the overall timing of the network and is always the parent device for other
MultiHop radios. The host system connects to this master radio. Repeater radios extend the range of the
wireless network and slave radios are the end point of the wireless network.
For more information, refer to the Sure Cross MultiHop Radios Instruction Manual (p/n
multipath fade
Obstructions in the radio path reflect or scatter the transmitted signal, causing multiple copies of a signal
to reach the receiver through different paths. Multipath fade is the signal degradation caused by these
obstructions.
network ID
The Network ID (NID) is a unique identifier you assign to each wireless network to minimizes the
chances of two collocated networks interfering with each other. Assigning different NIDs to different
networks improves collocation performance in dense installations.
node
A node is any communications point within a network.
Node
Nodes are remote I/O slave devices within Banner's wireless sensor networks. Sensors and other
devices connect to the Node's inputs or outputs, allowing the Node to collect sensor data and wirelessly
transmit it to the Gateway. Every Sure Cross device is a transceiver, meaning it can transmit and
receive data.
noise
Noise is any unwanted electromagnetic disturbances from within the RF equipment, especially the
receiver. Noise is more of a concern when signal levels are low.
omni-directional
antenna
Omni-directional antennas transmit and receive radio signals equally in all directions.
out of sync/link
loss (loss of
radio signal)
The Sure Cross wireless devices use a deterministic link time-out method to address RF link interruption
or failure. When a radio link fails, all pertinent wired outputs are sent to the selected default value/state
until the link is recovered, ensuring that disruptions in the communications link result in predictable
system behavior. Following a time-out, all outputs linked to the Node in question are set to 0, 1, or hold
the last stable state depending on the value selected.
path loss
Path loss describes attenuation as a function of the wavelength of the operating frequency and the
distance between the transmitter and receiver.
path loss (or
link loss)
calculations
Link loss calculations determine the capabilities of a radio system by calculating the total gain or loss for
a system. If the total gain/loss is within a specific range, the radio signal will be received by the radio.
Total Gain = Effective Free space loss + Total received power
. Because the transmitter
Sure Cross
®
DXM100-Sx Wireless Modbus Slave
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