#garfield Logs

Feb 24 2020

12:41 AM rue_mohr: looks like grbl uses floats for position, so the machine size should not be an issue
11:41 AM Tom_itx: https://www.amazon.com/NEMA23-381OZ-SHAFT-STEPPER-KL23H2100-35-4B/dp/B07MBPWKPZ
11:41 AM Tom_itx: shows a torque curve but i dunno if that's what you're after
07:08 PM rue_mohr: thats soemthing!
07:08 PM rue_mohr: phase would be nice, but ok
07:08 PM rue_mohr: (slip)
08:33 PM rue_shop1: ok
08:33 PM rue_shop1: so I can trip a CMOS flipflop with an ethernet transformer
08:33 PM rue_shop1: with the cmos running on 12V
08:33 PM rue_shop1: up to 3Mhz
08:34 PM rue_shop1: but I cant do any duty
08:34 PM rue_shop1: at 1Mhz I can go from 25% to 80%
08:34 PM Tom_L: what logic would you need to control 2 pumps as such:
08:34 PM rue_shop1: charge pump or just isolation to pumps?
08:34 PM Tom_L: alternate pumps running on low conditions but if flood, run both pumps
08:35 PM Tom_L: so each time every other pump would run unless high water
08:35 PM Tom_L: can be done with logic gates and a flip flop i think
08:36 PM Tom_L: just the low voltage control for the pumps
08:41 PM Tom_L: how do you trigger a flipflop from it's ouput or can you? so each time the other leg is active
08:52 PM rue_shop1: ?
08:52 PM rue_shop1: you just want a cycle divider for the pumps?
08:53 PM Tom_L: uh huh, but they both need to trigger in a flood situation
08:53 PM rue_shop1: we do that on all the sewer lift stations
08:53 PM rue_shop1: you just alternate master and backup
08:53 PM Tom_L: seemed like a common thing
08:54 PM rue_shop1: do you want to do it in 5V or with relays
08:54 PM Tom_L: somebody else was asking if a rpi would work and i suggested just a couple discrete logic chips
08:55 PM Tom_L: but i didn't bother to draw it
08:56 PM rue_shop1: no, I know, but I'm just wondering how you want to implement it
08:56 PM rue_shop1: in the systems that use relays, there is an actual mechanical alternation relay
08:56 PM Tom_L: it doesn't matter to me. it was just an exercise as far as i'm concerned
08:56 PM rue_shop1: every time you energize the coil, it toggles
08:56 PM rue_shop1: you hold the coil during the cycle
08:56 PM Tom_L: cool
08:57 PM Tom_L: what energizes both in the event of a flood?
08:57 PM rue_shop1: I suppose its 50/50 between relays and plcs
08:57 PM rue_shop1: well, the alternation relay just swaps who is master and who is backup
08:57 PM rue_shop1: behind it, the master is activated on normal cycle
08:58 PM rue_shop1: and the high float (or sensor) kicks in the secondary (and alarm)
08:58 PM rue_shop1: it gets fun when each motor also has a monitored overload
08:58 PM Tom_L: so there exhists devices that do this already
08:58 PM rue_shop1: well
08:58 PM rue_shop1: there is a drywell control box
08:58 PM Tom_L: or a plc
08:59 PM rue_shop1: its a 11(?) pin 'relay'
08:59 PM rue_shop1: a fat one
08:59 PM rue_shop1: does the alternation and everything
08:59 PM rue_shop1: iirc $300, but that can be less than us designing one up with parts
08:59 PM Tom_L: i just figured you would know
08:59 PM Tom_L: don't waste time on it
09:03 PM rue_shop1: it kinda bothers me that this isolator can do from 4Mhz to 10Hz (I didn't bother going lower)
09:04 PM rue_shop1: there are a few systems
09:04 PM rue_shop1: most elaborate is 4 floats
09:04 PM rue_shop1: lowlow low high highhigh
09:04 PM rue_shop1: normal cycle is between high and low
09:04 PM rue_shop1: highhigh kicks in secondary pump & alarm
09:04 PM rue_shop1: lowlow kicks in alarm
09:05 PM rue_shop1: cause it usually means your pump didn't stop
09:05 PM Tom_L: true
09:05 PM rue_shop1: er, "lead" and "lag" is what I was trying to recall
09:05 PM rue_shop1: the alternator swaps the rolls every cycle
09:19 PM rue_mohr: do you want to make one up?
09:21 PM Tom_L: naw i was just pondering it after he asked
10:08 PM Tom_itx is now known as Tom_L
11:40 PM rue_mohr: k, I need auto timing belts
11:41 PM rue_mohr: I'm swirreling towards building a buddy a cnc for his plasma cutter so I can get some parts made
11:43 PM X704 is now known as tiwake