Banner SureCross DX80 Wireless Networks - Manual (Page 22)

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Banner Engineering Corp. • Minneapolis, MN U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
SureCross Wireless Network
Product Manual
Site Survey
Site Survey from Modbus Commands
All DX80 models reserve the Modbus register I/O 15 (write only) for control messages. The control message code for the Site Survey
command is listed below.
To start a Site Survey using a Modbus write holding register command, send a control code of 32 (0x20) and the Node number 1–15 (0x01 to
0x0F) to the Gateway Modbus holding register for I/O 15.
Modbus Register
I/O 15 Control Code Data Field
I/O 15 Control Messages
Control Code Data Field Restrictions Description
32 Node # 1–15 Gateway Only Enable Site Survey between Gateway and Node defined by the data field. All error messages from
the Gateway are ignored when running Site Survey.
Only one Node can participate in Site Survey at any given time. To disable the Site Survey, use
control code 0x20 with Node 0. A Node must be enabled to run the Site Survey, then disabled
before selecting the next Node.
Example Command
I/O 15 32 02
When Site Survey runs, the accumulated results are stored in the Gateway’s I/O 7 and I/O 8 holding registers. The LEDs on the both the
Gateway and the Node’s front panel display the signal strength for the wireless RF link. The quality of the communications link is indicated by:
• LED 1 – Green = excellent signal strength
• LED 2 – Yellow = good signal strength
• LED 1 – Red = poor signal strength
The signal strength is the transmitted signal strength relative to the ambient RF signal present in a specific location, or noise floor.
The Gateway device also displays the Site Survey results on the LCD. For one transmit and receive interval, the Gateway saves the lowest
signal strength. The LCD and Modbus registers contain the results of the last 100 samples. The totals are a running tally of the last 100
samples and are continuously updated. Four categories are displayed:
• M = Missed packet • Y = Yellow – good signal strength
• R = Red – poor signal strength • G = Green – excellent signal strength.
To disable Site Survey, send a control code of 32 (0x20) and a Node number of 0 (0x0).
Site Survey Data Holding
With Site Survey active, Modbus registers I/O 7 and 8 are Site Survey data holding registers that store the accumulated Site Survey results.
Error collections in holding register 8 are saved when Site Survey runs and restored after Site Survey is disabled.
Modbus Register
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
I/O 7 Red Total Missed Total
I/O 8 Green Total Yellow Total
Example Results
I/O 7 10 0
I/O 8 80 10
Note: This is the current register arrangement when using Modbus/TCP or Modbus RTU. In some older models, the Modbus/TCP registers are
reversed (missed and yellow totals are in bits [8:15], red and green totals are in bits [0:7]).