Hello,
I'm working on a projet and we need to drive 130 stepper motors.
Each stepper is independant.
We want to make 1 turn on each stepper at a different time, and repeate this sequence.
Thanks
How much current do the stepper motors need? They are the kind with 2 coils each?
You can have 130 stepper motor drivers, which is probably expensive.
You can have 1 stepper motor driver and a bank DPST or DPDT relays, one per stepper.
DPDTs can be had for as low as $1.63 (1-lot) for 2A rated parts, such as EC2-5NU.
Then simple open drain shift registers to turn on 1 relay at time, 17 of them for up to 136 outputs.
I'll draw a picture of my concept, will take a few minutes.
The stepper motors are "Nema 17 Bipolar Stepper 12v 0.4A 40Ncm(56.7oz.in) 17HS15-0404S"
Ok, that relay and this concept should work well then.
One leg of all stepper coil A are connected in parallel, same for one leg of Coil B.
2nd legs are connected in parallel on the other side of the relay.
The shift register turns on 1 relay at a time to connect 2nd leg of A/B to the stepper controller.
(+5/Gnd & decoupling cap for shift register not shown, along with coil power & protection diode for each relay.)
http://www.omc-stepperonline.com/download/pdf/17HS15-0404S.pdf
On our project it's possible that at a certain time a lot of stepper motors function in the same time, is your concept compatible with this ?It depend of the stepper driver?
I'm sorry but i'm a french mechanical engineer, so i'm not an expert in electronic.
We want to make 1 turn on each stepper at a different time
is not the same as
it's possible that at a certain time a lot of stepper motors function in the same time,
To turn on multiple steppers at the same time, multiple stepper drivers are needed.
You could have several groups of steppers, perhaps 16 in each group, and allow 1 from each group to turn "at the same time". 9 at a time.
Or groups of 8, with 1 from each group, so 16 or 17 at a time.
Depending on the stepper driver/relay current capacity, multiple relays in a group could closed at one time and multiple steppers driven in parallel.
Does that help?
jerome38:
Hello,I'm working on a projet and we need to drive 130 stepper motors.
Each stepper is independant.We want to make 1 turn on each stepper at a different time, and repeate this sequence.
Thanks
One question that has not been covered is: do your stepper motors need to hold their position? If so, they need to be continuously powered. If they just move and then are free, the relay method will work.
Paul
If the guy can afford 130 stepper motors he can afford 130 stepper motor drivers (such as a Sparkfun Easydriver or Pololu A4988) and they will make life enormously easier.
The real challenge will be getting 130 different step (and direction ?) signals - especially if the motors need to move quickly.
...R
Stepper Motor Basics
If go with Easy Driver, still need a demux scheme from uC to 130 sets of DIR/STEP control pins.
SPI.transfer() out to 17 shift registers is quick, just a few tens of uS needed with data from an array.
Continuously powered vs move & disconnect needs to be answered by jerome38.
A Adafruit Motor Shield V2.3 is I2C and chainable.
CrossRoads:
If go with Easy Driver, still need a demux scheme from uC to 130 sets of DIR/STEP control pins.
https://cdn.sparkfun.com/datasheets/Robotics/EasyDriver_v45.pdf
Of course
SPI.transfer() out to 17 shift registers is quick, just a few tens of uS needed with data from an array.
I presume that would work with Easydrivers as well as with any other driver.
BUT ... can a single Arduino manage the computations needed to generate independent pulse streams for 130 motors ?
...R
Thanks for all your aswers.
My customer is looking to reduce the number of stepper motors, so when i know the number I will see how to do.
jerome38:
My customer is looking ....
How much are you charging him for our free advice ? ? ?
...R