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Appendix H - Trouble Shooting
Status LED
When all is good, the LED will be off and flash on for 100 milliseconds at the below rate. If there is a fault
detected and shown in the STAT parameter, the LED will be on and flash off for 100 milliseconds.
Protocol
ASCII
MODBUS
MANTRABUS II
MantraCAN
CANopen
Diagnostic Flags
The main diagnostics facilities are by means of the flags. See Command List for full description of the flags and
their meanings.
The flags are normally used something like this.
FLAG is read at regular intervals by the host (like the main output value, but generally at longer intervals)
If some warnings are active, i.e. FLAG is non-zero, then the host tries to cancel the warnings found by writing
FLAG= 0
The host then notes whether the error then either remains (i.e. couldn't be cancelled), or if it disappears, or if it re-
occurs within a short time, and will take action accordingly.
The warning flags are latched indicators of transient error events: By resetting the register, the host both signals
that it has seen the warning, and readies the system to detect any re-occurrence (i.e. it resets the latch).
What the host should actually do with warnings depends on the type and the application: Sometimes a complete
log is kept, sometimes no checking at all is needed.
Often, some warnings can be ignored unless they recur within a short time.
Warning flags survive power-down, i.e. they are backed up in non-volatile (EEPROM) storage.
Though useful, this means that repeatedly cancelling errors which then shortly recur can wear out the device non-
volatile storage – see Finite Non-Volatile Memory Life in appendix.
STAT provides a current status of the device. These flags are not latched and not saved on power fail.
No Communications
The majority of problems involve a failure to communicate, as there are a number of optional settings that must
be set the same at both ends of the link.
For this reason, any communications application should always check command responses, and flag a problem
when there these responses are not activated.
Possible problems can be categorised according to where in the 'chain' of communication the problem may be.
The typical chain runs as follows,
• PC software (port connection, baud rate, station number, protocol)
• PC USB (working)
• PC CAN drivers
• USB-CAN device
• Bus wiring
• Device (wiring, ID, bit rate, working)
Mantracourt Electronics Limited
LED flash period
0.5 seconds
1 second
2 seconds
0.5 seconds
As per CiA specification
112
DSC/DLC User Manual
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