Hi,
you say you are using an ESS but what BoB are you using?. I'm beginning to wonder if the buffer/output circuit of
your BoB is not fast enough. Do you have a scope or access to one? I think to resolve whether the ESS or the BoB
or the driver is responsible is going to require a scope to diagnose.

The second issue is the inductance of the steppers. Certainly at no or low loads you would expect a stepper to spin quickly
but at higher loads the same stepper will stall or lose steps. Without a close comparison of the rotational load it
not really possible to compare one installation to another.

Do you have a torque and inductance spec for your steppers? What brand/make/model are they?

Craig

Thanks Craig,
I think that may be my issue !!
I couldn't get a BOB in the UK when I first built my machine so I made my own Opto pcb for the inputs for 36v Inductance switches, the outputs are direct to the ESS. I'll have to see what I can buy now or I need to look at output buffer design to make my own  .

regards

Carl

Hi,
I think you are right. Opto-isolators can be as slow as a wet week depending on the model and how you set them up.

I have attached a pic of two very common optocouplers. Note that the phototransistor in one has no external base connection.
Thus the sole way it can turn on is light from the photodiode, thus the photodiode needs to brightly illuminate the phototranistor,
commonly 10mA or more. Typically the time response is slow, 10-20us with these devices and you would struggle to
pass a 100kHz signal through it.

The other optocoupler pictured has an external connection to the base. That is typically biased to about 0.6V such that the
phototransistor is on the threshold of conduction. Thus the light from the photodiode need be very much less intense
to cause the phototransistor to conduct, less than 1mA photodiode current. Response time is likewise much
improved, of the order of 1us.

The extra biasing circuitry, especially being so heat sensitive, means that the biased photocouplers are used only as needed
in comparison to the simpler non-biased optocoupler.

The question is why are you so hung up on optoisolators? Firstly its common for the input of stepper driver to have optocouplers
built in already. There is no need to isolate at the ESS/BoB end and THEN AGAIN at the driver end.

I use:

https://www.homanndesigns.com/index.php?main_page=product_info&cPath=54_22&products_id=59&zenid=n2f38qp4ho6mv9eb9rm7hhp7a0

from Homann Designs in Australia, I live in New Zealnd so they are kind of local to me. These are very simple and plain
bi-directional BoBs WITHOUT optoisolators. I've been using them for over five years and have not blown anything
up yet, and I can blow stuff up real easy!

If fact I did a poll a while back:

https://www.machsupport.com/forum/index.php?topic=39723.0

Only five people replied, a bit disappointing, but none of those five people (100%) have blown up a PC because they did
not use opto-isolators. I'm not saying you can't blow up a PC but it doesn't happen much either.

The advantage of the Homann BoBs is that without the opto's they are as fast as the TTL buffers used, ie tens of MHz.

The C10 is cheap enough, $23USD and bi-directional. Note it has no bloody opto's . Neither does it have any relays
for the spindle nor a PWM to analog circuit for a VFD, you would have to make and add those as required.

https://cnc4pc.com/c10-bi-directional-parallel-port-interface-card.html

Craig

Thanks, ive ordered a C10,  dont know how long shipping will take. I'll update when its arrived and tried out. Im only using the opto's on the inputs for the 36v switches.
Carl.

Hi,

Im only using the opto's on the inputs for the 36v switches.

OK, that makes sense. I suppose then that you do not have any buffering between the ESS and your drivers?

According to the specs the ESS should source or sin 24mA, surely that would be enough to drive the input optocouplers
of your stepper drivers. Do you have a circuit diagram of the input circuits of the drivers? I'm wondering if they are 24V
tolerant, in which case they are likely to have a series current limit resistor but may then reduce the current to borderline
or below when driven with the 5V outputs of the ESS.

Craig

All I have is the below from e-bay, not the most helpful support, may be the language barrier.
 
1, Stepper Driver Specifications :


Model
HBS57
Type
32Bit DSP Closed loop stepper drive
maximum peak current
5A/Pha
Impulse response frequency
Max. 200KHz
Micro-stepping driver
2-256  subdivision, Max 51200ppr
Voltage
DC24V-60V
Protective function
Over voltage, over current, tracking error, overproof
Signal input
Support PUL/DIR and CW/CCW modes (difference)
Compatible 5~24V signal (Don’t need a resistor)
Advantage
no step to lose, Low noise, little vibration and high efficiency, low heat
Continuous overload
Output an alarm signal
Type of cooling
Natural cooling
Alarm, position signal
Yes
Impulse type
Single impulse (Default), double impulse (need modify by soft)
Size
118*75*34(mm)
2, Stepper Motor Specifications :


Step angle/phase
1.8 degree
Rated voltage/current
4.52V/4A
resistance
1.13ohm
Inductance
3.6mH
Hold torque
3NM
Encoder
1000line
Class of insulation
B
Rotor inertia
800 g.cm2

Carl

Hi,
that's made by Leadshine. Manual attached.

Craig

Thanks Craig,

My drive is not labelled as Leadshine, though it looks the same.

I'll sort the rs232 leads out to check the parameters with the Pro-Tuner software, if it works.

I'm going to sort my wiring as well as I've daisy chained the supplies to the drivers, in fact I'm going to just run this drive on it's own with the ESS without the rest of my hardware to try it.

The set up time for the step signals is 2.5us and the current requirement is 10ma, so the ESS should be ok if I read and understand that right.

Anyway i'm getting the barbie out for easter Sunday, unbelievable for Manchester in April !!

Thanks for your help.

Carl.

Hi,

My drive is not labelled as Leadshine, though it looks the same.

Man.... a Leadshine copy???....the Chinese getting ripped off by whom....some other Chinese outfit??

So what brand is it?

The set up time for the step signals is 2.5us and the current requirement is 10ma, so the ESS should be ok if I read and understand that right.

I think that the current limit resisitor is such that with the low input voltage (5V) that the current is insufficient to reliably
and quickly signal the drive.

Craig

I finally got the C10 BOB for Port 1 of the ESS. This has not made any difference to this issue.

The motor is strong up to the point when it just stops, no loss of torque, so it's definitely just not responding to the faster signal.

On the plus side 'Fast to Buy' gave me a 70% refund and let me keep the motor and driver becaus they could solve my issue, so i've used it on my X Axis anyway as it is a lot smoother and quieter and than the open loop drives.

I'll have to post and see if anyone has any recommendations for motors and drivers to use on the ESS.

Carl.