We’ve all been there.
A critical device won’t perform just before the boss is supposed to show up with his boss to see your
new, magnificent accomplishment/development/process. And you can feel the panic rising in your
throat. What do you do first?
The key is to identify the actual problem and not work to fix symptoms. So start by defining, “not
working”. Did it ever work or are you working with a new measurement? Does it appear to be “dead”
or just not giving you the expected results?
First –
If it worked and then stopped, does it pass the sniff test? If you smell burned material or smoke, its
probably gonna be a long day. We all know electronics runs on smoke and it doesn’t work when you let
the smoke out. Consider substituting a known working device until the boss leaves.
Second –
Assuming you still have the smoke contained, check the power supply. Is the device “plugged-in”, or
connected to instrument power? Is the source even on? We know it sounds too simplistic, but roughly
1/5 of our trouble calls are solved by this question.
NOTE: If you have doubts and IF YOU ARE QUALIFIED to make a live measurement, take your trusty
multi-meter (you do have a trusty multi-meter, right?) and check to be sure the correct voltage level is
present on the terminals.
TIP: All of us have tried to measure DC with the selector on AC (or vice versa) so remember to set the
meter to AC or DC, as required.
Third – Is the process running? Again, IF QUALIFIED, check voltage inputs with a properly set Multi-
meter. Are you measuring the voltage you expect?
NOTE: Some devices will have inputs up to 600 Volts AC and 1500 Volts DC.
THESE ARE LETHAL VOLTAGES
If you’re not a licensed electrician, or authorized by your company to work with this stuff,
call someone over who is. None of this is worth dying over.
You can check to see if the current is flowing with a clamp on ammeter. It won’t be
particularly accurate, but it will let you know current is present. If you have Voltage and
Current present, then move to the next step.
Fourth –
Does it require programming? Many sensors are now programmable and won’t perform correctly (if at
all) without the correct programmed parameters. Was this device properly initialized? If so, (here’s
where it can get painful) does it have the correct program? Remember, GIGO!
Fifth –
If it still isn’t working as expected, and the above check out, you may have a wire or two in the wrong
place(s) or a CT reversed. Some manufacturers still have technical support and application specialists
who may be able to trouble shoot your situation over the phone.
If yours doesn’t, it will take more time than you probably have before the boss shows up; but, once you
tell them “how good it’s gonna be”, head over to the “CT Polarity” and “Getting Phases Right” blogs for
further steps.
Sixth –
This one is rare, but it does happen. You spend 30 minutes on the phone with a specialized support
person and confirm the wiring is correct. The specialist concludes you may have an internal component
failure. Most reputable manufacturers have a 0.5% (or less) "component failure rate" but “stuff”
happens to everybody. Murphy is the one person we can never fire (reference to Murphy’s Law, for the
newcomers).
If you’re fortunate, the manufacturer has a world-class warranty return policy that receives the
transducer back, identifies the suspect component (such as a defective IC, broken wire, etc.,) then
replaces/repairs/recalibrates and returns the device in a timely manner for years of reliable operation.
If you don’t get that response, then we recommend finding a different source for the future. Everyone
has occasional issues. How someone handles issues distinguishes “world-class” from junk – and life is
too short for that much frustration.