User manual

Geo Brick User Manual
78 Troubleshooting
Once the watchdog timer has tripped, power to the Turbo PMAC must be cycled off and on, or the INIT/
hardware reset line must be taken low, then high, to restore normal functioning.
Diagnosing Cause of Watchdog Timer Trip
Because the watchdog timer is designed to trip on a variety of hardware and software failures, and the trip
makes it impossible to query the card, it can be difficult to determine the cause of the trip. The following
procedure is recommended to figure out the cause:
1. Reset the Turbo PMAC normally, just power cycle the cycle ower. If it does not trip again
immediately, there is an intermittent software or hardware problem. Check for the following:
• Software events that overload the processor at times (e.g. additional servo-interrupt tasks,
intensive lookahead) or possible erroneous instruction (look for firmware or program checksum).
Review the Evaluating the Turbo PMAC’s Computational Load section of the Turbo USERS manual.
• 5V power-supply disturbances
• Loose connections
2. If there is an immediate watchdog timer trip in Step 1, power up with the re-initialization switch
pressed and hold in. If it does not trip now, there is a problem in the servo/phase task loading for the
frequency, or an immediate software problem on the board. Check for the following:
• Phase and servo clock frequencies vs. the number of motors used by Turbo PMAC. These
frequencies may need to be reduced.
• A PLC 0 or PLCC 0 program running immediately on power-up (I5 saved at 1 or 3) and taking
too much time.
• User-written servo or phase program not returning properly.
3. If there is an immediate watchdog timer trip in Step 2, check for hardware issues:
• Disconnect any accessories and cables other than the logic power and repeat to see if they are
causing the problem
• Check for adequate 24V power supply levels (check at the Geo Brick connector side, not at the
supply)
• Inspect for hardware damage
5. If the watchdog insists after all the above, you should contact DeltaTau Inc. to get an RMA number,
and ship the drive for repairs.