Not knowing the actual process/ hardware that exists etc. I think people may be over thinking this, most dipping processes I have come across the tanks are large enough to take the components with spare room all round, if this is the case then why go to to the extremes of hi res encoders or other methods that cost a lot more, difficult for many maintenance staff to faultfind on. sometimes simple is best.
On a side note: the coating process how is the PH controlled I assume this is manual at the moment.
I agree Parky that simple is sometimes best. And you're right about the clearance. I've got 1.5" clearance all around the square baskets that will be dipped into the containers. Millimeters of accuracy not required.
I was ready to go with the arrangement you mentioned in your earlier post until I read Gary's post. His mention of it lasting 20 years grabbed my attention. The laser distance sensor struck me as a good idea to keep from installing about 20 limits (for 8 dipping containers, home, and end stops). And my runway being only about 19', I can get a laser sensor for under $500. SEEMs like the way to go, but I'm holding back from pulling the trigger, while I learn from you veterans. What a valuable site this is. I'm it here in this little factory, when it comes to automation and controls, and now it's like I've got mentors. Can't tell you how much I appreciate it.
The $500 laser I’m considering (
https://www.automation24.com/laser-distance-sensor-ifm-efector-o1d100-o1dlf3kg) outputs 4-20mA, and it doesn’t seem too difficult to scale and calibrate. The baskets in the process are all equidistant. It just seems one of these would be simpler than the 20 limits, though I will still have the end stops and maybe home.
It sounds like I have a choice between a star wheel and an encoder to control the hoist dip length. And you’re right about the short dip length, parky, it’s about five or six feet. I can also imagine controlling the speed of the hoist and then clocking how long it takes to arrive, and put that timing into the plc, but that might be asking for trouble. I’m back to thinking an encoder will be best for the hoist. I see a lot of incremental encoders to choose from for under $300.
When I originally balked at encoders, I was reacting to using a rack-and-pinion linear encoder for the trolley location. That would work great, I’m sure, but I imagine more headaches at installation compared to the limits/laser. Limits or laser distance sensors seem preferable for the trolley, and an encoder or star wheel for the hoist.
To answer your pH question, the pH adjustments will be carried out manually for now. That presents an automation project for the future.