XT09-SI-MESH Digi International, XT09-SI-MESH Datasheet - Page 47

• Manufacturer Part Number: XT09-SI-MESH
• Description: MODULE RF 900MHZ 1W 115K W/RPSMA
• Manufacturer: Digi International

Specifications of XT09-SI-MESH

• Frequency: 900MHz
• Modulation Or Protocol: FHSS, FSK
• Power - Output: 1W
• Sensitivity: -100dBm
• Voltage - Supply: 2.8 V ~ 5.5 V
• Current - Receiving: 80mA
• Antenna Connector: RP-SMA
• Operating Temperature: -40°C ~ 85°C
• Package / Case: Module
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Applications: -
• Memory Size: -
• Data Interface: -
• Data Rate - Maximum: -
• Current - Transmitting: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 602-1183

XTend™ RF Module ‐ Product Manual v2.x6x
Repeater Network Configuration
A network may consist of End Nodes (EN), End/Repeater Nodes (ERN) and a Base Node (BN). The
base node initiates all communications.
A repeater network can be configured to operate using Basic Broadcast or Basic Addressed com-
munications. The addressing capabilities of the module allow integrators to send a packet as a
global packet (DT = 0xFFFF) and shift out of every module in the network (Basic Broadcast). Alter-
natively, the packet can be sent with a specific DT (Destination Address) parameter so that it is
only accepted by a specific remote node (Basic Addressed).
Configuration Instruction (Basic Broadcast Communications)
The configuration instructions above reflect configuration for a Basic Broadcast Repeater system.
To configure a Basic Addressed Repeater system, use the DT (Destination Address) parameter to
assign unique addresses to each module in the network.
Algorithm Details
Packets may be shifted out the serial port and/or repeated depending on the DT parameter con-
tained in the RF packet.
Table 4‐02. DT (Destination Address) parameter truth table
Repeat Delay Based on RSSI
A transmitted packet may be received by more that one repeater at the same time. In order to
reduce the probability that the repeaters will transmit at the same instant, resulting in a collision
and possible data loss; an algorithm has been developed that will allow a variable back-off prior to
retransmission of the packet by a repeater. The algorithm allows radios that receive the packet
with a stronger RF signal (RSSI) to have the first opportunity to retransmit the packet.
The RN (Delay Slots) parameter is used to configure this delay. Set RN=0 (no delays) for small
networks with few repeaters or repeaters that are not within range of each other. Set RN=1 for
systems with 2 to 5 repeaters that may be within range of each other.
The actual length of the delay is computed by the formula:
Where L is the length of the transmitted packet in milliseconds, DS is the number of delay slots to
wait, RSSI is the received signal strength in dBm, RN is the value of the RN register and Rando-
mInt(A,B) is a function that returns a random integer from A to B-0
Assign each module a unique MY (source) address. (The AM (Auto-set MY) command will con-
figure a unique source address that is based on module serial number.)
Enable Basic Broadcast Communications (DT = 0xFFFF) or Addressed Broadcast Communica-
tions (DT specifies a specific destination)
Configure PK, RO and RB to ensure that RF packet aligns with protocol packet. (ex. PK=0x100,
RB=0x100, RO depends on baud rate).
Configure one or more repeaters in the system (MD = 5).
Configure remote nodes as destinations (MD = 6). This will ensure that the remote node waits
for the repeater traffic to subside before it transmits a response.
© 2010 Digi Internatonal, Inc.
• Packet ID (PID) is composed of TX (transmitting) module MY address and packet sequence
• Incoming packets with a PID already found in the PID buffer will be ignored.
• Each module maintains a PID buffer 4 deep of previously received packets (managed as
Delay (ms) = L * DS
DS = (-41-RSSI)/10*RN)+RandomInt(0,RN)
number.
FIFO).
Address Match
Global
Local
None
Send out serial port?
Yes
Yes
No
Repeat?
Yes
Yes
No
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