Selection of the appropriate motors to the machine is very individual. Designer practice shows there is a dilemma – what solution should be chosen. Not so long ago – because of high prices of servo drives, in the simpler machines usually the stepper motors were used. Today, the technological progress and the dissemination of the servo technology causes that building a machine – even like a hobby – it’s worth to consider servo drives. The most common mistake while decision-making is the power selection (and torque) of the servo drive. It happens because we are suggested by torque and holding torque. The first parameter is usually given with the servo drives and the second with the stepper motors. Both are usually in the same unit Nm (Newton – meter). Do not compare these parameters when you are choosing servo drive power. Holding torque in the stepper motors is a power that the shaft of the powered motor in standby mode is held in position. When the revs are very low – something about 200 rpm – the torque is almost the same, but with increasing revs the torque, (actually the power on the motor shaft), decreases drastically. It decreases to such low values that sometimes happens that at 1000 rpm. the motor has no power to work itself, not saying about propelling the machine. In the simple words: the 3Nm stepper motor, reaches 3Nm torque on very low (200 rpm.) revs, when the revs increase its power decreases to zero. It is completely different in the servomotors. First, the torque and the rev speed are nominal. Therefore, the 1Nm/ 2000 rpm motor can operate continuously with revs: 2000 rpm. and at this speed provides 1Nm of the torque on the shaft. Besides the servomotors have another one important feature: they can be temporarily overloaded. What does it mean? That the 1Nm motor can temporarily deliver even 2,5-4Nm (it depends on the type). If we use the motion controller with fast STEP outputs like CSMIO/IP-S, the important parameter of the motor drive is maximum frequency of the steps. Controllers with higher frequency limit of STEP signal allow you to use higher stepper division (for the stepper motors) or encoders with larger pulses number per rev (servo). However, everything has its pros and cons. So what are the disadvantages of servo drives? They are certainly more expensive – how much, it depends what kind of stepper and servo drives you compare. There are e.g. stepper motors controllers that cost 800 USD and there are some other that cost 40 USD (with the same power!). Generally we can conclude that the servo motor + drive package is more expensive. Other disadvantage of the servo drives is necessity for PID controllers tuning and wiring that is more complicated. That will be the end of the disadvantages. Great advantage of the servo drives is that – thanks to the feedback – the servo drive indicates the overload and positioning error. When the CSMIO/IP-S receives this signal immediately stops the axes. In the stepper motors there is no feedback like this one, so even if one of the axis because of e.g. overload will not keep the set trajectory, the machine will continue the work – breaking the same entire processed detail. In sum – we recommend the servo drives. Their disadvantages are negligible in comparison to the benefits they offer. Please note that the servo drive can have much lower nominal torque than holding torque of the stepper motor. When we compare the 3Nm stepper drive and 3Nm servo drive – the price difference may be significant. However, if we compare the 3Nm stepper drive with the 1Nm servo drive, the price distance is not so big. Practice shows that sometimes – mechanically identical machines are sold in two versions, with 3Nm stepper and 1Nm servo drives. The machine with the stepper motor reaches max 7,5m/min feed rate and 0,1g. acceleration. The machine with the servo drive reaches 20m/min feed rate and 0,4g. acceleration. If we add the feedback, which was mentioned before, further comparing is pointless. The choice is in your hands of course, in some solutions the stepper motors are adequate and work very well. Thanks to perfectly precise STEP signal timing of the CSMIO/IP-S controller the stepper motors behave much better then while controlling from e.g. the LPT port. We can use a higher stepper division, so the motors will work quieter, smoother and they get higher revs by reducing the resonance.
On our website you can download standard scripts for handling automatic measurement of tool-length and for automatic tool replacement. These are usually the most desirable functions and make the work easier. For advanced users we invite to learn more about macros, which provide great opportunities for self-expanding functionality of Mach3 program.
The simple example here – shows the E-Stop signal connection to the CSMIO/IP-S controller and to the axis drives, using Pilz company safety relay (PNOZ X7 24V symbol). S1 is a reset button (safety relay switching on), S2 is an emergency stop. This module has one input, and due to it, all the alarm sources are connected to this input (A1). In addition to the mentioned emergency stop (S2) there are NC contacts – NC1 and NC2, which may be, i.e. opening sensors for the cover and the control cabinet. Moreover, there are drives’ FAULT signals connected in series. Two outputs of the safety relay were used as an E-Stop signal for the CSMIO/IP-S controller and axis drives. This combination assures the machine stops in case of failure on any axis (FAULT signals of the drives), by pressing emergency stop mushroom and opening of the cabinet or cover. Separation of the safety relay output channels gives double protection for the system and significantly increases the reliability of the entire system.
CS-Lab technical support team will answer any further questions, you can also count on our technical advisory in case of doubts while connecting, configuring, launching and using CS-Lab devices.
Here and here – you will find block diagrams explaining how the cooperation of various types of servo controls is conducted. Most modern servo-drives have the ability to control via step/dir, some of them have also the additional feedback e.g. scales (linear encoders). The step/dir digital signal carries two pieces of information: current axis position (pulses number) and movement speed (STEP signal frequency). The servo-drive counts the impulses and measures the signal frequency. All PID controllers are tuned in the drive and the drive ensures that the axis is always in desired position. If- because of e.g. overload – servo is unable to maintain to keep the position precisely enough – then it reports an error to the CNC controller and a machine work is stopped. The CSMIO/IP-S controller works with these drives. For an example – our clients are using drives such as Kollmorgen (S600), Yaskawa, Delta Electric. For classical control system purpose and for the possibility to connect some old-type (+/- 10 V) servo-drives there is another controller – CSMIO/IP-A. In this CNC controller the regulation is divided – current and speed part is realized in the drive and the position – in the CNC controller. In such a solution there is necessity to connect an encoder to the controller and tune the position PID controller. As shown in the drawings, both solutions have the same components, different is just the division of tasks made by system components. Step/dir control type has the advantage that the control signal is transmitted digitally and all motor control loops are in the drive, synchronized with each other, making this system work more precisely. However- analog control allows you to connect some old servo-drives, which can be a great advantage for people who want to retrofit their control system on old-type tool machine.
A) Yes, it is.
B) You need PC with an ethernet LAN port and 32-bit Windows system (the 64-bit platform wasn’t tested yet). 24V DC power supply.
C) Yes, it is. Please look at the” 10.6 Configuration of spindle and cooling controlling” chapter in CSMIO IP/S manual
D) We have MPG module in our offer too. This is the only way to connect jog wheel to our controller. You can buy just only CSMIO-MPG module or MPGKit (CSMIO module + handheld rotary encoder).
A) Threading is possible with additional module for spindle encoder connection CSMIO-ENC.
B) Every G and M code supported by Mach3, should work with CSMIO/IP-S.
C) The Toolchange works without any problems, e.g. you can look at this movie. We have example macro for it.
Mach3 needs plugin which you will get with your order in the package (CD) or you can download it from our website (DOWNLOAD – CSMIO/IP-S – Release)
In the CSMIO/IP-S controller there were some things to improve in previous versions, currently V2 version that was carefully tested is in sale and works without any bugs in many machines. Of course there always can be found something to improve. If we get information about some unforeseen problem our reaction is immediate and new version of Firmware can be downloaded from our website, it takes only 30 sec.
Yes you can use other pendant. You will find all information and schemes in CSMIO-MPG User Manual.
CSMIO/IP-S and IP-A controllers are very similar, the main difference between them is that IP-A controls motor drives through +/-10V analog signal, and IP-S – through STEP/DIR signals. CSMIO/IP-A is targeted rather for older machines retrofitting, because most of old servodrives can be controlled only by +/-10V signal. For new applications IP-S is better choice, for example because of the possibility of mixing stepper and servo motors in one application. Most of modern servodrives can be controlled both +/-10V and STEP/DIR.
The best option to use linear scales is CSMIO/IP-A. Motor encoder is then connected to motor drive as velocity feedback and linear scales are connected to CSMIO/IP-A as position feedback. But you have to check if linear scales has compatible outputs (should be differential, quadrature signals).
CSMIO/IP devices don’t support closed loop for stepper motors. In case of servo systems, there is always a closed loop. With CSMIO/IP-A you can see actual position on Mach screen even if servo power stage is disabled and IP-S controller ‘trusts’ that servo drives are keeping good positions until there is no Alarm signal from the drives. But when servo powerstage is switched off (for example in case of ESTOP event) IP-S doesn’t know actual position and user must re-reference the machine. On the other hand STEP/DIR solution (IP-S) has better dynamic, because STEP/DIR are digital signals and don’t need to be filtered in the motor drive like analog signal from IP-A controller. The other important advantage of IP-S is possibility to mix servo and steppers, because most of modern servo drives can be controlled by STEP/DIR signal like every stepper driver.
First – do you want to leave old drives or use new drives and motors?
You need a PC, we often use mini-ITX boards and mount it in control cabinet. I recommend at least ATOM 1.6GHz, but if you want to do more complex files (> 10MB) then best choice is something about Core i3 and min 2GB of RAM. I also recommend SSD drive because it is more reliable. It is also a good idea to buy board with two ethernet ports or additional LAN controller, one is used then for CSMIO/IP connection, and second for local network which is convenient and the safest solution. If you wish to leave old drives, you have to look for their documentation. Sometimes it may be problematic… Most of old drives are controlled by +/-10V signal, so CSMIO/IP-A will be the best choice. Anyway you have to check encoder outputs (from the drive) and most important signals like Servo-Alarm, Servo-Enable, Alarm-Reset and of course Speed-Ref analog input.
If you wish to change the drives for new ones, then you can choose between IP-S and IP-A, because most of modern servo systems can be configured either to STEP/DIRECTION or analog mode. STEP/DIRECTION has better dynamic, because analog signals have to be filtered in the drive first. You will need some additional stuff like +24VDC powersupply, relays, etc. It depends on what exactly equipment have to be controlled. Sometimes (especially on machines with automatic toolchangers) additional IO module is necessary. Consider also CSMIO-MPG module for MPG pendant connection to set-up machine in comfortable way.