Anybody wants a stepper motor analyzer?
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@rjenkinsgb said in Anybody wants a stepper motor analyzer?:
The TMCS1101A4BQDT from Mouser.
I've now got the boards programmed.
The display is showing continuous slight variations in the current with nothing connected so I'd guess the sensors are giving a slight "noise" output, +/- a few tens on mA reading while nothing is connected.And I've just realised I do not have any suitable connectors to intercept the stepper motor end of the machine cables!
(The Duet end is fully harnessed & laced so it's not practical to lift single connectors at the board).
I want to be able to connect at the motors anyway, as I'm using E3D toolboards so the board connections for the direct tools are totally different from the axis motor feeds.
I'll see if I can find stepper extensions with appropriate connectors that I can hack up..
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@rjenkinsgb Which connectors do you need? I just received a my order of the WURTH connectors (similar to the Duet 5+ or Duet 2). They look similar to yours on the board. I could send over a couple if you're willing to wait and part with some beer money.
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@th0mpy
That's a good question at the moment there is almost nothing to buy, so I'll take the one that is available again first. So ACS70331EOLCTR-2P5B3 or TMCS1101A4BQDT -
@th0mpy said in Anybody wants a stepper motor analyzer?:
Which connectors do you need?
The six pin 2mm pitch headers, as fitted to stepper motors, to make an inline adapter for that end.
I have plenty of four pin KK ones, thanks.
At the moment the 2mm pin headers are like gold dust - 27p on RS but out of stock, or anything up to £10 EACH on ebay.
I found some back-to-back headers to connect two motor cables together, so I can use one of those as the inline connector & I have a few spare motor cables to make up the adapters.
(They cost around ten euros, but for a pack of 16). -
@dogma2k With either of those you should not need a jumper on the options. They both have 400mv/a rating, so you should be good.
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@rjenkinsgb What about just some stepper motor cables, and hack the end off? Something like this maybe: https://www.amazon.com/RuiLing-Stepper-Motor-Cables-HX2-54/dp/B07QHTG82K/ref=sr_1_3?keywords=stepper+motor+cable&qid=1637721866&sr=8-3
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@th0mpy said in Anybody wants a stepper motor analyzer?:
What about just some stepper motor cables, and hack the end off?
I have those already - it's the mating header connector I need, so I can unplug from a motor and connect "inline" between that cable and the motor.
These, in other words:
https://uk.rs-online.com/web/p/pcb-headers/1755419/
https://www.ebay.co.uk/itm/143627995609I got a pack of these instead, and I can use two motor cables on the analyzer with one of these to link to the existing motor cable:
https://www.ebay.co.uk/itm/383225801147(I'm not buying from the profiteering sellers on principle).
Six pin plug to socket extension cables would have been ideal, but I cannot find any place actually in the UK selling them.
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The Mouser TMCS1101A4BQDT ICs seem to work perfectly!
I've made a harness to connect in to the axis motor sockets on the control box, which is fine for those (but the extruders are run from individual toolboards).
[I have printed an enclosure, but then discovered I don't have any thin double-sided tape to attach the display... I'll get some later on].
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@rjenkinsgb, very nice build!
A couple of notes:
- Theoretically the analyzer needs only 4 wires to measure the currents of the two coils. You can build a harness that has only 4 wires with Y splitting on both ends.
- For double sided tape for the TFT, I had good experience with this kind of thermal tapes. They hold well and designed to be isolating. https://www.amazon.com/gp/product/B072JJD2ND . I also use them between the Pico and the PCB for extra isolation.
- You mention residual current (0.04A in the picture). I presume that you set the zero in the Settings screen.
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A question for the people that uses various current sensors, how do tell the firmware what is the mv/A sensitivity of the sensor you use?
I don't think that this kind of equipment needs to be supper accurate in the current measurement but it's nice to keep it reasonably close, e.g. +/-5%.
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@th0mpy
Thank you for your explanation.
I have now found a couple of TMCS1101A4BQDT that I wanted to order.It doesn't really matter what kind of stepper I analyze. I wanted to install the analyzer on my NEMA23 as a permanent display
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@zapta said in Anybody wants a stepper motor analyzer?:
A couple of notes:
- Theoretically the analyzer needs only 4 wires to measure the currents of the two coils. You can build a harness that has only 4 wires with Y splitting on both ends.
- For double sided tape for the TFT, I had good experience with this kind of thermal tapes. They hold well and designed to be isolating. https://www.amazon.com/gp/product/B072JJD2ND . I also use them between the Pico and the PCB for extra isolation.
- You mention residual current (0.04A in the picture). I presume that you set the zero in the Settings screen.
I realise only two through connections are monitored, but the harness needs two connectors at either end anyway..
To fix the display, I put a few strips of kapton on the back & over the rear of the motor connectors to ensure good insulation, then some generic thin double sided tape to hold things together.
Yes, it has been zero'd - the readings fluctuate randomly +/- a small amount with no connections. When I first turned the unit on, it read somewhere around 300 - 400mA on each channel.
It's a really nice design, the options and screen responsiveness are great. Playing around with it, I realised it can do for something else I have been intending to make for some time - an encoder tester for machine tool systems.
If I add a pair of analog differential inputs with selectable gain in place of the current sensors on one, it can monitor either sine or digital encoders & linear scale signals - pretty much just change the Amps indication for Volts!
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@zapta said in Anybody wants a stepper motor analyzer?:
A question for the people that uses various current sensors, how do tell the firmware what is the mv/A sensitivity of the sensor you use?
If you get some TMCS1101A4BQDT ICs, they are the same sensitivity as the original ones.
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@rjenkinsgb said in Anybody wants a stepper motor analyzer?:
TMCS1101A4BQDT
The datasheet of the TMCS1101A4BQDT suggests that it requires 5V supply. Does it work well with 3.3V?
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@zapta It seems that either 3.3v or 5v work just fine. The limits are just a little different.
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@th0mpy said in Anybody wants a stepper motor analyzer?:
@zapta It seems that either 3.3v or 5v work just fine. The limits are just a little different.
Good to know. Thanks. Yes, 3.3 will cause saturation for +/-5.75A @400mv/A but we don't need that full range, and it is specified for 3.3V for the other ranges.
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So that the prototype housing of the AWD Stepper Motor Analyzer fits quite well, just adjust a few small things.
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@dogma2k said in Anybody wants a stepper motor analyzer?:
AWD Stepper Motor Analyze
Wow! That's a nice design.
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Hey everyone, I have a new batch of sensors being delivered early next week. If you're interested hit me up via chat.
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The final case is finally ready. I also installed a FlowMeter. Everything fits in and the lid even closes.
If you like, you can download the STEP file
