Validity Of Process Data - WAGO I/O-SYSTEM 750 Manual

118 Diagnostics
The Mailbox command "GetLinkSignalStrength, 0xD7" can be used to
query the signal strength. If the radio connection has to bridge a long
distance, the RSSI is negative. Because the 750-644 I/O module has a very
sensitive receiver, a stable radio connection itself is still possible with an
RSSI value of -15 when the ambient conditions are invariably stable.
• Channel mask (AFH):
With Bluetooth
detected and own transmissions avoided. The channel mask provides
information about which of the 79 available frequency ranges is currently in
use. The channel mask can be read using the Mailbox command
"GetAvalailableChannelMap, 0xD8". The best transmission conditions exist
when all frequencies are available. By contrast, if only a few frequencies are
available, there are probably other radio systems with high transmission
power in the vicinity.
Depending on the operating mode and role configured, the 750-644 I/O module
indicates the signal quality in different ways:
• "Real-Time Communication" mode, operating as the master:
-
• "Real-Time Communication" mode, operating as a slave:
-
-
-
-
• "Ad-hoc Communication" mode
-
10.2.4

Validity of Process Data

Parts of the process image can be overlaid by the register communication,
parameter channel or Mailbox configuration protocols (see section "Process
Image" > ... > "Overlaid Configuration Protocols").
If overlaid in "Real-Time Communication" or "Ad-hoc Communication" modes,
data exchange with remote devices may be temporarily interrupted for one or
more slots. The relevant parts of the process image are then invalid in regards to
data transmission. The 750-644 I/O module thus indicates possible invalidity of
the process data in the input process image.
If bit 7 is set on the local 750-644 I/O module in the status byte (byte 0), register
communication is enabled. Is such case, neither the input nor output process
image contain valid process data, i.e. in this state, data cannot be sent to nor
received from remote Bluetooth
®
technology, interrupted frequency ranges are automatically
The specified Mailbox commands can be used to query status
information about the radio connections to the slaves.
LEDs B and F visualize the signal strength indicator.
LEDs C and G visualize the signal quality.
LEDs D and H visualize the channel mask.
The above Mailbox commands can be used to query status information
about the radio connection to the master.
The specified Mailbox commands can be used to query status
information about each radio connection.
750-644 Bluetooth
®
devices.
Version 2.0.0, valid from FW/HW Version 03/03
WAGO-I/O-SYSTEM 750
®
RF-Transceiver
Manual