poorly written vendor software

[rpoet]

Had a freaky occurrence today:
I was attempting to tune a new machine driven with a Parker DC servo motor and a Gemini GV6K controller. The "Motion Planner" software by Parker has a tuning utility that's supposed to allow you to perform a short low speed move and graph the results and adjust drive parameters accordingly.

The move was supposed to be a 6-ish inch move up (the machine is a small stage elevator that carries scenery) over about 20 seconds. I had the distinct feeling that I shouldn't really trust this software, as it's obtuse and reads like stereo instructions, so my left hand was hovering over the E-stop while my right hand clicked MOVE.

The elevator took off like a scalded dog in the down direction (it was supposed to go up, slowly ). I figure my response to the sound of the servo trying to exceed the speed of sound was a little less than a second. In that time, the elevator dropped 3+ feet. Glad I put the elevator in the middle of it's 10' travel before this little adventure began.

I came really close to utterly destroying a set piece first thing this morning - not the best way to start a week. Needless to say, I did the tuning manually from there on out.

Parker certainly isn't the only offender, but how can vendors justify releasing half-finished and just-plain-wrong software to support their hardware? I got lucky today; someone else might end up damaging some expensive equipment, or even worse hurting someone. Just a crappy move on vendors' parts, as far as I'm concerned.

On the other hand, the new E-stop system got a real-world test. It passed with flying colors.


-rpoet

[Peter Nachtwey]

Did you do a polarity check first? You should make sure that a positive output generates a positive direction move by do a small jog. It sounds like the the controller was still in closed loop with the polarity of the output not setup correctly.

Closed loop systems with the polarity wrong will take off like a scalded dog.

[RussB]

IMHO,
When big expensive equipment or human life is at stake it is always a good idea to power up and do first run tests with motors disconnected from other moving parts. Even if it means more time and a second tune-up after all is connected.

[rpoet]

Peter,
I'm sure I was ultimately the one who did something incorrectly to cause our motor to take off like it did. However, the software is unclear and unfinished (it's riddled with spelling mistakes, for instance). I'm sure you're right about having incorrect settings causing the move. The trouble was, I didn't know what I didn't know.

My gripe is more about shoddy software not letting the user be clear about what's about to happen. Motion Planner from Parker is OLD software; the software and the Gemini drives it was written for first came out in the late 90's. Old software shouldn't be an excuse for allowing bugs and issues to persist.

Parker is trying to phase out that line and move to their new Aries controllers, which I'm told are much more user-friendly all around. motion Planner is essentially obsolete, but I'm stuck with it for now. I'll continue to use it for downloading configs to the drives, but not so much for tuning.


-rpoet

[danw]

I've seen it over and over again. The development of most industrial software seems to be farmed out to low bidder Asians who work/live in cubes without a clue as to how the software is actually used. It's low cost and low performance.

A software package meets marketing's need to say "there's software" and they don't get graded on its performance.

I've seen numerous inquiries on control sites that are clearly from programmers in Asia, wondering about basic terminology and 'how things work' and "what does this mean?". They're trying to figure out how to code what's they now have a contract to deliver.

Sounds like you have a stellar example of such.

[LadderLogic]

Originally Posted by danw

The development of most industrial software seems to be farmed out to low bidder Asians who work/live in cubes without a clue as to how the software is actually used. It's low cost and low performance.

Just look at Beckhoff's I/O rack configuration software (KS2000). In this case, I would rather picture a German schoolboy doing some side work while on vacation...