Instruction Manual

Conducting a Site Survey (Gateway and Nodes)

A Site Survey, also known as a Radio Signal Strength Indication (RSSI), analyzes the radio communications link between the Gateway

and any Node within the network by analyzing the radio signal strength of received data packets and reporting the number of missed

packets that required a retry.

Perform a Site Survey before permanently installing the radio network to ensure reliable communication. Activate Site Survey mode from

either the Gateway buttons or the Gateway Modbus holding register 15. Only the Gateway can initiate a Site Survey, and the Site Survey

analyzes the radio communications link with one Node at a time.

Conducting a Site Survey Using the Menu System

Initiate a Site Survey using the Gateway’s buttons and menu system.

1. Remove the rotary dial access cover.

2. To check the status of Node 1, change the Gateway’s right rotary dial to 1.

The Gateway is now enabled to read the status of Node 1; the display scrolls through the Node’s I/O status.

3. Single-click button 1 to scroll across the menu levels until reaching the Site Survey (SITE) menu.

4. Single-click button 2 to enter the Site Survey menu.

5. Single-click button 2 to begin conducting a Site Survey with the Node selected in step 2.

The Gateway analyzes the quality of the signal from the selected Node by counting the number of data packets it receives from the

Node.

6. Examine reception readings (M, R, Y, G) of the Gateway at various locations. Note that the numbers displayed are a percentage. M

displays the percent of missed packets while R, Y, and G display the percentage of received packets at a given signal strength.

M = Percentage of missed packets; R = RED marginal signal; Y = YELLOW good signal; G = GREEN excellent signal. Record the

results if you need troubleshooting assistance from the factory.

7. Change the Gateway's right rotary dial to conduct a Site Survey with another Node and repeat steps 2 through 6.

8. To end the Site Survey, double-click button 2.

9. Change the Gateway's right rotary dial back to 0.

The LCD displays the device readings for the Gateway.

10. Double-click button 2 to move back to the top level menu.

11. Single-click button 1 to return to RUN mode.

12. Install the rotary dial access cover, referring to the Installation section of the manual to create an IP67 seal.

Conducting a Site Survey Using Modbus Commands

A Site Survey can be started using Modbus commands sent from the host system.

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

[15:8] [7:0]

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 ena-

bled to run the Site Survey, then disabled before selecting the next Node.

Conducting a Site Survey and Interpreting the Results

Datasheet 7/2/2013

PAGE 1
Conducting a Site Survey and Interpreting the Results Conducting a Site Survey (Gateway and Nodes) A Site Survey, also known as a Radio Signal Strength Indication (RSSI), analyzes the radio communications link between the Gateway and any Node within the network by analyzing the radio signal strength of received data packets and reporting the number of missed packets that required a retry. Perform a Site Survey before permanently installing the radio network to ensure reliable communication.
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Conducting a Site Survey and Interpreting the Results Example Command Modbus Register 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.
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Conducting a Site Survey and Interpreting the Results Result Description Yellow Packets received at a good signal strength. A good signal is between −90 and −100 dBm at the receiver. Red Packets received at a weak signal strength. A weak signal is less than −100 dBm at the receiver. Missed Packets not received on the first transmission and requiring a retry.