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 indica-
ted 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:
• G = Green – excellent signal strength
• Y = Yellow – good signal strength
• R = Red – poor signal strength
• M = Missed packet
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, 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.
Register
[15:8]
[7:0]
I/O 7
Red Total
Missed Total
I/O 8
Green Total
Yellow Total
Example Results
[15:8]
[7:0]
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 regis-
ters are reversed (missed and yellow totals are in [8:15], red and green totals are in [0:7]).
Interpreting the Site Survey Results
Site Survey results are listed as a percentage of data packets received and indicate the signal strength of the received signal.
Result
Description
Green
Packets received at a strong signal strength. A strong signal strength is
greater than −90 dBm at the receiver.
Yellow
Packets received at a good signal strength. A good signal is between
−90 and −100 dBm at the receiver.
SureCross Wireless I/O Network Manual
rev. I
www.bannerengineering.com - tel: 763-544-3164
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