Lowrance HDS-7 Gen3 Installation Manual US - Page 36

Diagnostics, Damping

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Diagnostics The NMEA 2000 tab on the diagnostics page can provide information useful for identifying an issue with the network. Bus state: This simply indicates whether the bus is powered, but not necessarily connected to any data sources. However if bus shows as 'off', but power is present along with an increasing error count, it is possible that termination or cable topology is incorrect. Rx Overflows: The CAN driver got too many messages for its buffer before the application could read them. Rx Overruns: The CAN hardware got too many messages for its buffer before the CAN driver could read them. Rx/Tx Errors: These two numbers increase when there are error messages, and decrease when messages are received successfully. These (unlike the other values) are not a cumulative count. Under normal operation these should be at 0. Values around 96 upwards indicate a heavily error prone network. If these numbers go too high for a given device, it will automatically drop off the bus. Rx/Tx Messages: Shows actual traffic in and out of device. Bus Load: A high value here indicates network is near full capacity. Some devices automatically adjust rate of transmition, if network traffic is heavy. Fast Packet Errors: Cumulative counter of any fast packet error. This could be missed frame, or frame out of sequence etc. NMEA 2000 PGNs are made of up to 32 frames. The entire message will be discarded when a frame is missed.  Note: The above information may not always indicate an issue that can be simply resolved with minor adjustment to network layout or connected devices and their activity on the network. However Rx and Tx errors are most likely indicating issues with the physical network, which may be resolved by correcting termination, reducing backbone or drop lengths, or reducing the number of network nodes (devices). Damping If data appears erratic or changes too rapidly, damping may be applied to make the information appear more stable. With damping set at MIN, the data is presented in raw form with no damping applied. This is available for heading, course over ground, speed over ground, apparent wind, true wind, boat speed, depth, and tide sourced from NMEA 2000. 34 | Software setup | HDS Gen3 Installation Manual

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34 |
Software setup |
HDS Gen3 Installation Manual
Diagnostics
The NMEA 2000 tab on the diagnostics page can provide
information useful for identifying an issue with the network.
Bus state
: This simply indicates whether the bus is powered, but not
necessarily connected to any data sources. However if bus shows as
‘off
’, but power is present along with an increasing error count, it is
possible that termination or cable topology is incorrect.
Rx Overflows
: The CAN driver got too many messages for its buffer
before the application could read them.
Rx Overruns
: The CAN hardware got too many messages for its
buffer before the CAN driver could read them.
Rx/Tx Errors
: These two numbers increase when there are error
messages, and decrease when messages are received successfully.
These (unlike the other values) are not a cumulative count. Under
normal operation these should be at 0. Values around 96 upwards
indicate a heavily error prone network. If these numbers go too high
for a given device, it will automatically drop off
the bus.
Rx/Tx Messages
: Shows actual traffi
c in and out of device.
Bus Load
: A high value here indicates network is near full capacity.
Some devices automatically adjust rate of transmition, if network
traffi
c is heavy.
Fast Packet Errors
: Cumulative counter of any fast packet error.
This could be missed frame, or frame out of sequence etc. NMEA
2000 PGNs are made of up to 32 frames. The entire message will be
discarded when a frame is missed.
Note:
The above information may not always indicate an issue that
can be simply resolved with minor adjustment to network layout
or connected devices and their activity on the network. However
Rx and Tx errors are most likely indicating issues with the physical
network, which may be resolved by correcting termination, reducing
backbone or drop lengths, or reducing the number of network
nodes (devices).
Damping
If data appears erratic or changes too rapidly, damping may be
applied to make the information appear more stable. With damping
set at MIN, the data is presented in raw form with no damping
applied. This is available for heading, course over ground, speed
over ground, apparent wind, true wind, boat speed, depth, and tide
sourced from NMEA 2000.