Frequently asked questions about ELS

Which cycles can the ELS run?

Actually, these are:

  • Long Turn Outside
  • Long Turn Inside
  • Facing Cutting Off
  • Automatic Threading Outside Inside, with Any Pitch
  • Tapered Threads
  • Multi-Turn Threads
  • Taper Turning (Inside + Outside)
  • Radius (Inside Outside Convex and Concave)
  • Drilling
  • Groove Turning
  • Grinding
  • Angle Measurement
  • Gear Mode

Can I also turn inch threads with it?

Yes! Any thread pitch is possible, in 0.001mm increments. The thread pitch must therefore be converted into mm and entered. The flank angle can be entered from 0-90°. It is therefore really easy to turn every conceivable thread, without changing gears.

What about multi-start threads?

Yeah, that’s possible too. After each thread you turn the chuck in the desired angle and set the angle to 0, then you turn the next thread. This way, any number of threads are possible as long as there is room on the shaft.

Can tapered threads also be made?

Yeah, that’s possible too. A taper ratio can also be entered for threading. Internal and external tapers are possible.

Which maximum travel distance can I set?

The ELS can measure and move to positions up to a maximum of 9999.99 mm. Up to 10 m long lathes are therefore feasible.

How exactly can I set the pitch feed?

The feed rate is adjustable in 0.001mmU steps.

My machine is type XY from manufacturer AB, can I attach the ELS there?

In principle, the ELS can be attached to any lathe as long as an encoder can be mounted on the spindle and a stepper or servo motor can be attached to the X and Z axes. The drives must be designed in such a way that they can handle the load, which is not always easy to appreciate with large machines.  ELS has already been installed on small watchmaker lathes, but also on a 3-ton machine for threading heavy castings. The axis drives must be able to accept step direction signals, that is a condition. Some servo systems cannot do this, you have to take that into account.

Can I also connect servo motors?

All drives that accept step direction signals can be used. You should make sure, however, that the drive does not require more than 1000 steps per motor revolution, some servo drives require more pulses, which are then unsuitable or would limit the maximum possible feed rate. However, since a lathe requires rather slow movements, stepper motors or hybrid servo motors (=”Closed Loop Stepper Motor”) are fully sufficient, servo motors have no real advantage in the application. Especially cheap servo motors have the disadvantage that they have to be adjusted exactly to the machine, whereas stepper motors or hybrid servo motors are immediately ready to drive.

My machine has an inch lead screw, can I use it?

This is possible, you have to convert it to mm and then you can enter the value as the leadscrew pitch. This goes up to 0.001mm.

My motor driver can only do 2000 steps rev

Some stepper motor output stages (e.g. Beast) do need 2000 steps revolution. These are not suitable for the Z axis, as they would reduce the maximum possible feed rate on the Z axis too much.

Can I also use an encoder type XX?

In principle, you can use any encoder that delivers approx. 400 pulses per revolution and signals A and B. An index signal is not necessary. In addition, the encoder must run with 5V operating voltage and the output signals must be TTL 5V. It is ideal if it supplies A, A, B and B, i.e. differential signals, then it can be connected without a line driver.

Do Baumer encoders work, too? (Hollow shaft encoder)

The same applies: 5V TTL output always works, the pulse rate must match. Important for the types: Observe the installation instructions and distances, especially the installation direction is very important.

What is the Differential Line Driver for?

The driver converts the signal of the AMT 103-V encoder into a differential signal. A HIGH is simultaneously transmitted as a negated signal, which increases the interference immunity. Interferences that are scattered into the signal line are filtered out again at the end.  You can also use an encoder with differential signals, then you don’t need the line driver. The nice thing about the type AMT 103-V is its adjustability, you don’t have that otherwise. Unfortunately it needs the line driver for this.

Can I connect an external control unit?

The ELS 4 has a SUB-D connector for connecting an external control unit. A finished device is in preparation, for self-made devices there is an adapter board in the shop.

Can the ELS also control a frequency inverter?

The ELS 4 Pro can control a frequency inverter via a 0-10V output and via 2 outputs for StartStop. The ELS 4 Basic does not have these functions.

Can I connect glass scales?

No, glass scales or other measuring systems cannot be integrated.

Can the ELS run several cycles in succession?

No, each cycle must be started individually.

How do I set a new feed rate? I don't see a keyboard

All settings are made with the rotary knob, so you can set new values very quickly, because the step size of the input is adjusted. The knob can still be pressed to adjust smaller increments. In this way you simply rotate the values, which is much faster than with a keyboard.

What is the maximum feed rate?

The maximum feed rate in mmrevolution is directly linked to the ratio of encoder pulses, motor stepsrevolution and the feed rate of the master spindle. The maximum feed of the ELS  is

Fmax = (4 x Encoderimpulses x Leadscrewpitch) / Motorsteps


Encoderimpulse: 400 Impulse/rev
Motorsteps: 400 Steps/rev
Leadscrewpitch: 4mm

Fmax = (4 x 400 x 4) / 400 = 6400/400 = 16mm / rev

Rarely you need 16 mm/rev, so in this case you can set the motor steps to 800 (at the output stage AND in the ELS Settings!) to get a softer run and 8 mm/rev as maximum feed. If the step rate of the stepper motor is increased, the maximum feed rate is reduced! A reduction ratio changes the value accordingly, this must be taken into account!

You should aim for the maximum value you need, most lathe operators rarely drive over 8mm/rev, then you can adjust the system to it.

Which Linux runs on the ELS?

Haha, good question, none at all. The ELS has an 8 bit ATXmega controller as its computer heart. The software is also only about 200 KB small. So there is a very small controller inside, which is very powerful due to clever programming and a good compiler.

Can I have the source code? I would like to develop this further myself

No. It is not an open source because it is written in Avrco-Pascal, whose compiler is not free but expensive, and which only a few use. Avrco Pascal is a powerful system apart from the C mainstream, but thanks to Pascal it is very well suited for microcontrollers and generates fast code. The code is very easy to read and maintain, and thanks to Pascal there are less traps to fall into than in C. As you can see at the ELS you can realize complex realtime controls on relatively slow controllers.

Frequently Asked Questions about Setup

I want to run my axle with a 1:1,75 ratio

It is not advisable to choose a crooked translation, unless you can use it to straighten a “crooked” inch leadscrew pitch, but this rarely succeeds. In general, the drive values should result in round numbers, so that the controller must output an exact number of steps, e.g. for 0.01 mm travel distance. With crooked values this is often no longer possible. At 1:1.75, one motor revolution becomes 0.571 leadscrew revolutions, a very crooked value.

I want to drive my Z-axis with a 1:2 ratio to double the torque.

This is possible, but the maximum possible feed rate and the traversing speed of the Z axis are halved. It is therefore recommended to set the step rate of the stepper motor only to 400 so that the limitation is not too high. Better is always 1:1, if necessary with a correspondingly stronger motor. In the settings one must consider this accordingly, since the motor must now turn 2x for a spindle rotation one must double the number of steps of the motor in the ELS.

A stepper motor runs the wrong way, what can I do?

You can either reverse the winding connections on the output stage, or you can reverse the direction of the motor in the settings of the ELS. The latter is easier.

Is it possible to install the encoder the other way round?

Yes, this is possible because the direction of rotation of the encoder can be reversed in the controller to compensate for this.

Can I also use an encoder with more than 400 pulses per revolution?

Yes, this is possible, but it should be noted that the maximum spindle speed of the ELS is 3000 rpm if 400 pulses/rev are used at the encoder. At 800 the maximum speed is only 1500 rpm, at 200 the maximum speed is 6000 rpm. The reason is the finite computing power of the controller. At some point it can no longer process everything.

How do I set the pulse rate of the encoder?

The pulse rate of the encoder should be 400. The encoder itself must be set to 400 (with 4 small switches on the encoder!) and the controller must also be set to 400 in the settings.

How do I get to the Settings?

Press the settings button (wrench symbol).

My axis moves only half as far as indicated, what can I do?

The step rate of the stepper motors is set at the output stages with the small DIP switches, usually 400 or 800. The same rate must also be set in the settings of the ELS. If the values are different, the travel distance will not be correct later. Basically, the values set on the hardware (encoder, stepper motor output stages) must also be adopted in the settings of the ELS.

The displayed rotational speed is not correct.

In this case, the setting of the encoder or the encoder setting in the controller is not correct.

The setting of the encoder pulse rate in the controller must always correspond to the real pulse rate per spindle revolution! If an encoder with 400 pulses is used, the setting in the ELS must also be 400.

If the encoder has a 2:1 ratio, the setting must be set to 800, since the encoder rotates twice with each spindle revolution and therefore emits 2×400 pulses.

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