How can I troubleshoot Firewire problems?

If you're experiencing noise in a Firewire system or it seems to drop-out intermittently the following troubleshooting points need to be done to pinpoint what the issue may be. This is a lot to absorb, but there is no easy answer without monitoring the drives.

In a good operating system, once the Firewire powers up and gets done handshaking with all of the modules, the parameters BUSS RESETS, MY BUSS RESETS and the BAD MESSAGE should not be increasing on the FIREWIRE function block. There will be numbers for these parameters, but once they get done handshaking they should stabilize and not increase. If there are a lot of Buss Resets and My Buss Resets on all the drives, that is not good and indicates an issue somewhere. There should be no more than a couple hundred on each parameter at most.

1. First make sure that the FireWire cards are powered correctly.
   • The IEEE1394 bus requires a separate, floating 24 Vdc (12-24 Vdc) supply connected to Connector X42
   • NOT connected to the same 24Vdc supply that is connected to X13
2. To see where the problem may be coming from monitor the BUSS RESETS, MY BUSS RESETS and the BAD MESSAGE parameter on the FIREWIRE block.
3. Monitor these at each drive while the drive is powered up, but not in the RUN mode. When the IGBT's are not firing and generating noise.
   
   • If the MY BUSS RESETS is increasing, there is noise on the Firewire from some outside source.
   • If the BUSS RESETS & BAD MESSAGE are increasing it could be a bad Firewire card or Firewire cable.
   • If the parameter numbers are not increasing, it would appear that the hardware is good
4. Now RUN the drive and the motor. When the IGBT's are firing and power will be going to the motor and the motor leads.
   • Monitor BUSS RESETS & MY BUSS RESETS.  Are they increasing? If so noise from the IGBT's are getting into the Firewire.
     1. Maybe from the motor leads not being wired or grounded properly?
     2. Is the motor cable shielded? On both ends? Is it loose?
5. RUN one (1) drive at a time and repeat step four to see if the noise or problematic drive can be isolated.

If the LED on the Firewire card is a flashing Amber LED, or if the color is not in the list, it usually means the card is off in the weeds.

• A flashing amber LED MAY mean that the Buss is continually resetting

Important questions to ask:

How old is the system?

When was it started up?

Has it ever worked correctly?

When did the Firewire issues start occurring?

What changes were made recently?

LS MAR19

Updated/Formatted JD 14MAY19