Rexroth Indramat Snake Eyes


Snake Eyes, aka Drive Watchdog Trigger, is a fairly common error.  Most clients who need help with this don’t realize that’s why they need help. The display can present with what looks like (and is) junk — no recognizable error code. It’s called “snake eyes” because in addition to weird stuff, you’ll see two blinking lights.

So what’s going on?

Drive watchdog timer

When the drive watchdog timer triggers, it means that the drive processor has stopped cycling. Every time the processor completes a cycle, it resets the watchdog timer to zero. If the timer ever times out, it means that the processor is no longer working. It also means that the drive has suffered a “Snow Crash”, i.e. that the display memory has had digital garbage sprayed throughout it. This is also why you get what looks like Klingon on display.

However, the drive engineers took this into account. When the watchdog timer triggers, it is hardwired into the periods in the 9 segment displays. So, if the two periods are displaying, you can ignore the rest of the display, as it is meaningless.

Troubleshooting snake eyes

There can be two causes for Watchdog Error. The first is bad firmware, and the second is a bad drive. The only way to troubleshoot this problem further than simply knowing that one or the other is bad is to try out a known good drive.

If you have an appliance that doesn’t work and you’re not sure whether it’s the appliance or the electric plug that’s bad, you can bring a working lamp over to the plug and plug it in. If it works, you know the electric plug is fine. You can do the same thing to check on your snake eyes.

Power the drives down and move the firmware from the Snake Eyed drive to the known good drive.

DO NOT move the good firmware to the questionable drive. A bad drive will often toast good firmware, whereas bad firmware will not harm a good drive. It is okay to power up the questionable drive without firmware, but the next step is to power up the good drive. If the good drive with the questionable firmware powers up to anything other than Snake Eyes, the firmware is okay and the other drive needs to be replaced or repaired.

Now what?

If the firmware Snake Eyes on the known good drive, the firmware is certainly bad and the drive might be okay — or it might not. It is always a risk to find bad firmware, because the drive may have toasted the firmware with a drive failure as well. The smartest move is to replace both, and then send the units in for evaluation.

Of course this is the point where “It’s 10pm, do you know where your backups are”? as you will need to load a known good copy of the parameter set to the firmware module after you get everything else straightened out.

We have replacement drives and firmware for immediate shipment, and can offer phone support for problems that don’t present with obvious answers. Call 479-422-0390 for immediate tech support.

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Call (479) 422-0390 for immediate assistance

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