Phoenix Contact RAD-900-DAIO6, User Manual, Page: 117 / 140

Detecting and removing errors
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10 Detecting and removing errors
If the wireless system does not function properly, proceed as follows:
• First, ensure there is a good wireless signal (2 green bar graph LEDs or RSSI voltage
≥ 1.5 V).
• Check the status of the individual stations:
– If the PSI-CONF software is installed, check the device status of all network
devices via online diagnostics.
– If the PSI-CONF software has not been installed, check the bar graph LEDs on the
front of each device.
• Find the error using the tables from page 116 onwards.
Strength of the receive signal
Determine the strength of the receive signal by means of the RSSI voltage. The signal
strength is displayed on the LED bar graph on the wireless module.
– In a point-to-point connection, the LED bar graph is active on the master and on the
repeater/slave.
– In a wireless network with more than one repeater/slave, only the yellow LED on the
master is permanently on. The signal strength is displayed on the repeaters/slaves. The
displayed signal strength is always related to the next wireless module in direction of
the master (parents).
The RSSI indicator is a voltage output in the range between 0 V DC ... 3 V DC. The higher
the voltage, the better the wireless connection. The measured voltage is directly related to
the receive signal in -dB. However, please observe the small voltage fluctuation due to
multipath propagation.
The recommended minimum signal strength is 1.5 V DC. This results in a power reserve of
approximately 10 dB which ensures communication even in the event of unfavorable
transmission conditions.
Measure the RSSI voltage at the RSSI test socket or read it using the PSI-CONF software.
When connecting the master wireless module to a PC, you can read the RSSI voltages in
the entire wireless network. At a slave or repeater, it is only possible to read the RSSI
voltage of the specific wireless module connected.
Table 10-1 RSSI voltage
Avoid contact between the antennas of two wireless module, otherwise the receiver might
become overloaded.
Ground loops are caused by the grounding of the antenna via the antenna fixing unit,
grounding the power supply or serial interface. To avoid ground loops, connect these
components to a single ground point.
16k 125k 250k 500k RSSI
voltage
LED 3 -75 dBm -70 dBm -65 dBm -60 dBm 2.5 V
LED 2 -85 dBm -80 dBm -75 dBm -70 dBm 2.0 V
LED 1 -95 dBm -90 dBm -85 dBm -80 dBm 1.5 V
LINK LED LINK LINK LINK LINK ~1.0 V