rpoet
March 27th, 2012, 01:56 AM
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 :banghead:). 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
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 :banghead:). 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