#robotics Logs

Jun 23 2018

12:28 AM wenz: so i can wrap: while (ROBOG.ROBOG_OPERATING_STATUS(true)) {} around line 57 to 64 but some how i have to have ROBOG to get the ROBOG.ROBOG_OPERATING_STATUS(true)){} to be true and it will work some how
12:34 AM rue_shop3: I'm listening, but I cant help
12:35 AM wenz: could you have alook at the brain functionality section of the code
12:35 AM wenz: would that create a neuron for deeplearning
12:40 AM rue_shop3: no, the website your using requires pointless encryption thats beyond what my browser can do
12:53 AM wenz: ?
12:53 AM wenz: whaaa
12:53 AM wenz: ?
01:39 AM rue_shop3: google decided that all sites should use 256 bit encryption for everything
01:39 AM rue_shop3: my browsers only support up to 128, so I'm not allowed to access that site
01:39 AM rue_shop3: its stupid really, you see, every 2 years we bump it up,
01:40 AM rue_shop3: we should go to 1024 bit NOW
01:40 AM rue_shop3: be done with it for a while
01:47 AM Jak_o_Shadows: I kinda agree with that.
01:48 AM Jak_o_Shadows: Like, they more or less did that with IPv6, so why not go the full way elsewhere
02:26 AM * rue_shop3 counts teeth on a gear
03:26 AM rue_shop3: hmm
03:28 AM z64555: missing a tooth?
03:32 AM rue_shop3: no, done that bit
03:32 AM rue_shop3: have a 6:1 which is close to the 5.6:1 I was roughly aiming for
03:32 AM rue_shop3: but I need a position sensor
03:32 AM rue_shop3: its a servo
03:33 AM rue_shop3: and there is a problem because I cant get long shaft pots cheap
03:33 AM rue_shop3: I'm trying to figure out how I can use a 3362P-1 pot
03:33 AM rue_shop3: (rather solid like trim pot)
03:34 AM rue_shop3: or a magnetic or optical resolver
03:34 AM rue_shop3: or variable capacitor
03:35 AM rue_shop3: oh
03:35 AM rue_shop3: what about that
03:35 AM rue_shop3: if I took a theaded rod, and put a nut on it with a capacitor plate
03:35 AM rue_shop3: had the other plate static
03:36 AM rue_shop3: as the rod turned, it'd change the distance
03:36 AM rue_shop3: put that in an LC osc and use the freq as the result
03:38 AM rue_shop3: it'd need to hide in a metal can
02:33 PM rue_bed: yes, totally a variable capacitance or inductance thing
02:33 PM rue_bed: I wonder if I can make a var inductor based one without having magnetic side effects
06:06 PM rue_shop4: https://1.bp.blogspot.com/-SvA8pUV_LFE/U9Vl0ir9omI/AAAAAAAAB8Q/r1VQZOkX_5g/s1600/SN74LS629N+Oscillateur+1.png
06:11 PM Tom_itx: what happened today?
07:22 PM z64555: rue: not likely. Inductors are sensitive to any ferromagnetic materials near them (based on their size) and can pick up RF transmissions
07:24 PM z64555: variable-cap design may work, but you'll need a way of electricaly insulating the shaft. Also, the threads will interfere with the E-field, so you may need to place the plates in such a way so that the threades don't come near the E-field
08:03 PM SpeedEvil is now known as Guest49805
08:05 PM rue_shop3: easy ground the shaft
08:05 PM rue_shop3: Tom_itx, today or yesterday?
08:14 PM Tom_itx: yeah
08:24 PM rue_shop3: I'm making new test hardware for the force feedback servos
08:24 PM rue_shop3: I was going to use the old stuff, but one side of it is always falling apart, and the other side is geared too much
08:24 PM rue_shop3: this is funny, I "already had everything" do to this, and I'm building everything from scratch
08:48 PM rue_shop3: "so rue, what are we going to use as a baseplate for this project?"
08:48 PM rue_shop3: "..... your going to make this overly complicated, aren't you??"
08:49 PM Tom_itx: the usual path
08:50 PM Tom_itx is now known as Tom_L
08:50 PM Tom_L: rue_shop3, know much about VFDs?
08:50 PM Tom_L: as an electrician..
08:51 PM rue_shop3: oooh wait, I dont ahve to wait for that printer to finish, I have more of them
08:51 PM rue_shop3: Tom_L, yea
08:51 PM Tom_L: few questions i have are: can a VFD drive an AC servo motor if you ignore the encoder feedback on it and just use it as a regular AC 3phase motor?
08:52 PM rue_shop3: I know that they have a 90% chance of the two related trades not hooking up with each other properly and we end up having to deal with it
08:52 PM rue_shop3: none of the vfd's we work with have feedback
08:52 PM Tom_L: no, i realize that
08:52 PM Tom_L: i'm wanting to pair an odd couple
08:52 PM rue_shop3: they control the drive freq, I think that some of them are able to sense the true rpm
08:53 PM Tom_L: instead of a servo amp, use a VFD on a servo motor
08:53 PM rue_shop3: hmm
08:53 PM rue_shop3: servo motors are usually low voltage
08:53 PM rue_shop3: vfd's are usually full votlage
08:54 PM Tom_L: but if the voltage rating on the servo was say 220v and the VFD was 220v would they work together?
08:54 PM Tom_L: i don't know alot about either drive system
08:55 PM Tom_L: or a 120v system
08:56 PM Tom_L: for example:
08:56 PM Tom_itx: https://store.dmm-tech.com/products/dht-0-75kw-ac-servo-motor
08:56 PM Tom_L: is rated at 150v
08:58 PM Tom_L: is it true that reversing any 2 on a 3 phase will reverse it's direction?
09:06 PM k3g: Tom_L, yes
09:07 PM k3g: check this out: http://fab.cba.mit.edu/classes/865.18/motion/brushless/bldc-motor-vectors.gif
09:07 PM k3g: think about flipping any of the two sin waves
09:07 PM Tom_L: i knew the answer, i was just reassuring myself
09:07 PM k3g: :)
09:07 PM k3g: but the science behind it is the fun part!
09:08 PM Tom_L: i just don't know alot about VFD or servo amps and what they can drive
09:08 PM Tom_L: i'm just finding it hard to find an amp that will accept the analog input i have to use for it
09:09 PM Tom_L: most are +-10v and i've got 0-10v
09:09 PM k3g: can you set your zero to be 5v? you'd lose resolution
09:09 PM Tom_L: that or some serial or modbus protocol
09:09 PM Tom_L: i'm not sure
09:09 PM k3g: I'm not sure if I can help with generalities
09:10 PM Tom_L: i think the way it works is i have a 15v max swing so it may be possible to get 7.5v each side of it
09:28 PM z64555: dangit
09:28 PM z64555: my multimeter has gone awol
10:38 PM rue_shop3: tom sometimes the motors are rated for what the driver takes, not the motor itself
10:39 PM rue_shop3: tom I can set you up with a translation amp 0-10 -> -10->10
10:40 PM rue_shop3: :/ I need to make a 25mm hole in this plastic and I'm not sure how I wnt to do it
10:41 PM rue_shop3: I should use the cnc...
10:41 PM Tom_L: i need to come up with a -10v source too
10:41 PM z64555: bore saw won't work?
10:41 PM z64555: cnc probably more precise
10:42 PM rue_shop3: tom, do you know what current it needs?
10:42 PM rue_shop3: might be able to just use a 555
10:42 PM rue_shop3: you have 12V available right?
10:42 PM rue_shop3: have a 555? :)
10:42 PM * rue_shop3 waits for the cloud of tom dusting off the component cases
10:44 PM * z64555 see dust storm outside window
10:46 PM rue_shop3: arg, JIT manufacturing sucks, I WANT MY PARTS
10:50 PM Tom_L: it's a signal so probably fairly low current
10:50 PM rue_shop3: so a 555 charge pump should be able to do it
10:51 PM rue_shop3: hmm
10:51 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/cnc/BLDC/DYN4MS-ZM5-A18A.pdf
10:51 PM rue_shop3: I wonder if an op-amp can be the charge pump source for itself
10:51 PM Tom_L: unless you see a better way to control it
10:54 PM rue_shop3: 0.1mA eaasy
10:54 PM Tom_L: but how does that work with 2 inputs
10:54 PM rue_shop3: how about we build you a 0-10 -> -10-10 and see if it works
10:54 PM Tom_L: +10 on one and -10 on the other
10:55 PM rue_shop3: shoudldn't be
10:55 PM Tom_L: look at the pinout
10:55 PM Tom_L: on the DB25
10:55 PM rue_shop3: gnd, -10->10
10:55 PM rue_shop3: page 18
10:56 PM rue_shop3: see page 20? those are complimentrary signals
10:56 PM rue_shop3: not the ones on page 18
10:57 PM rue_shop3: thats dir too ya know
10:57 PM rue_shop3: page 37
10:58 PM Tom_L: yeah
10:58 PM rue_shop3: a good question I dont see the answer to tho
10:58 PM Tom_L: there are several modes it can be controlled by
10:59 PM rue_shop3: if you only give it 0-10V, AND use the direction signal, does it honour the dir?
10:59 PM Tom_L: idk
10:59 PM rue_shop3: maybe its off in servo mode
10:59 PM rue_shop3: k
10:59 PM rue_shop3: you have 0-10 as speed and a dir on/off signal dont ya?
11:00 PM rue_shop3: do you have a 555?
11:00 PM Tom_L: no
11:00 PM Tom_L: all my electronics are put away
11:00 PM rue_shop3: *blink* hahahahaha no seriously.
11:01 PM Tom_L: i am
11:01 PM rue_shop3: *blink*
11:01 PM Tom_L: it'd take a week to find anything
11:03 PM rue_shop3: you have to admit, -10-10 would be worth a lot to you right now
11:03 PM rue_shop3: 555 and an op-amp
11:03 PM rue_shop3: some diodes and caps
11:03 PM rue_shop3: and a few resistors
11:04 PM rue_shop3: dont make me build it here, I need my time for me
11:04 PM Tom_L: i'll find another way or scrap the idea entirely
11:04 PM Tom_L: keep your time
11:05 PM rue_shop3: well, its easy
11:05 PM rue_shop3: 555 can be substiuted with a max232
11:06 PM Tom_L: don't the 232 put out -v too?
11:10 PM rue_shop3: the max232 doubles and inverts the power supply
11:10 PM rue_shop3: so from 5V you can get +-11ish
11:10 PM rue_shop3: the 555 is a better option for making a -12V supply
11:10 PM rue_shop3: 600mA capable
11:11 PM rue_shop3: my two options are the cnc or the 4 jaw in the lathe
11:16 PM Tom_L: dude may have a board i can use he offered me
11:16 PM Tom_L: takes pwm/dir and puts out +-10 i believe