tips and hints for selecting servo motor and controller

[rod]

I would normally start this by saying what servo do I need, and leave the rest up to you guys... but I've already done this about 50 times and I'm finding myself going around in circles...



so i start

- what size motor do I need to do the work? in my case I need 1hp or 750W given ~ speed x torque = power

- what functionality do i need, I found PLC is not smart enough so I want the CNC functionality with G code. this brings me to Masso

- looks like a reasonable device to control a servo, So I go to the servo shop and he says use the svo 2100 driver from sureservo with an slv 207,

but as its not listed on Masso...given the complexity of this stuff I want to make sure I can just plug and play... and if i do have issues i can get help.

so masso tech says ask you guys!

is there something more user friendly, cost effective, reliable...

 

[breezy]

Have you looked at post Thinking of updating my cnc need advice.

Three of the best forum members have supplied answers there.

Regards,

Arie.

 

[rod]

Yeah, I have, problem is my power requirement is far higher than the normal cnc functions I'm driving timber into a rip saw, stop and cut to length. I can find a servo and drive through a repretible brand, but nothing to control it. I thought the command would be fairly universal but it appears that it's all a closely guarded secret.

 

[breezy]

OK,

So, maybe provide pics and full description of what you are doing, then we can provide answers.

Once we know what equipment you are going to use, connection to MASSO is quite easy.

Regards,

Arie.

 

[machinedude]

sure servo is automation directs brand of servo motor and drive. automation direct is a great source for things needed in a cnc build for sure but they are expensive as far as servo motors and drives go. DMM servo motors and drives are much more affordable and they work fine with Masso. they can be sized up to 1.8 kw if you need something bigger. 750 watts is 1 HP and I personally have 4 of those for the build I am working on. you can buy from them in a kit form and even get a discount on list prices. they are based in Canada but they offer pretty good customer service working through e-mail.

 

[dsherburn]

One thing to keep in mind is that most steppers rely on a "step and direction" set of signals (a pulse train) and are inherently open loop-meaning they typically dont have position feedback devices like an encoder. The controller spits out pulses equal to a linear distance (based on a rev/distance number) and the motor spins the required revs to get there. If it stalls, the controller probably wont know.

Servos (typically) use an analog signal (+/-10vdc) to control velocity and a controller looks at the encoder signal to close the position loop-meaning it's a true closed position loop. Having said that, there are a number of servos that accept a pulse (like a stepper would use). I'm not sure if Masso can utilize a +/- 10vdc speed command with encoder position feedback so you'll need to be aware of that. Sizing is a matter of torque and speed requirements (it can get involved)

Many here are using straight forward steppers like Gekko or Leadshine. Maybe others using servos can chime in.

 

[jcoldon]

I used them all not a clear path fan . best value is DMM they have a sheet they can email you. put in gear reduction pinion gear sizes and it calc max gantry weight.

the dmm4 are real ac servos . fast 3000 rpm fast. so your table needs to be able to handl them like linear slides . a top servo is a yaskawia sigma 7 drive

but for what you want dmm are good . they better then the clear path . I don't like having 5 volt signals for step direction out side the controller.

then watch.. clear path send you unshielded control wire so make your own if you use them . keep in mind the dmm4 ac servo so thers more power and faster they a better value

thers 4 diferent control in the drive you can program.plus no dc power supply.just ac power.. they work with masso no problem . hope fully masso can keep up with the servo I don't know masso frequency out put

I would think heigh enough

 

[machinedude]

Quote from dsherburn on May 30, 2019, 1:45 pm

One thing to keep in mind is that most steppers rely on a "step and direction" set of signals (a pulse train) and are inherently open loop-meaning they typically dont have position feedback devices like an encoder. The controller spits out pulses equal to a linear distance (based on a rev/distance number) and the motor spins the required revs to get there. If it stalls, the controller probably wont know.

Servos (typically) use an analog signal (+/-10vdc) to control velocity and a controller looks at the encoder signal to close the position loop-meaning it's a true closed position loop. Having said that, there are a number of servos that accept a pulse (like a stepper would use). I'm not sure if Masso can utilize a +/- 10vdc speed command with encoder position feedback so you'll need to be aware of that. Sizing is a matter of torque and speed requirements (it can get involved)

Many here are using straight forward steppers like Gekko or Leadshine. Maybe others using servos can chime in.

a stepper system is good at holding a position but as the speed increases the holding torque drops off like a stone. over sized motors is usually used to get past the chance of lost steps as a result. a stepper hybrid system closes the loop with a encoder but still suffers the draw backs of a simple stepper system with the loss of holding torque as the speed increases. a true servo system is a closed loop system and the torque speed curve is consistent across a wide range of speed.

servo systems have 3 main modes of operation 1 being a position mode. in this mode your using a step and direction system and the feedback is to the drive that closes the loop. when the feedback from the encoder get out of spec the drive faults and shuts it down. servo's also have a torque mode which I am not using so I can't really offer to much insight into that mode of operation. and finally they have a speed mode which runs on a analog 10vdc signal much like a VFD operates with masso. this mode is linked to the controller in the sense the encoder is hooked up to the masso controller and the drive as well.

one grey area to watch out for is the hybrid steeper area because often they make claims of it being a servo system but it is not in my opinion. they fall short in the performance over the torque speed curve. it is a closed loop system but not a true servo system.

 

[rod]

definitely was a quote from automation direct, the guy on the phone was great to talk to, knew servo motors, controllers and PLC well, although expensive I believe it is probably worth it to be able to call a guy for help!

the problem is that he wasn't confident with CNC in general, and Masso was even more outside his knowledge base. thats why I'm here!

thanks machinedude, for the tip on DMM have sent off a quote request, hoping to hear back in the morning.

 

[halfstep]

Quote from jcoldon on May 30, 2019, 2:44 pm

I used them all not a clear path fan . best value is DMM they have a sheet they can email you. put in gear reduction pinion gear sizes and it calc max gantry weight.

the dmm4 are real ac servos . fast 3000 rpm fast. so your table needs to be able to handl them like linear slides . a top servo is a yaskawia sigma 7 drive

but for what you want dmm are good . they better then the clear path . I don't like having 5 volt signals for step direction out side the controller.

then watch.. clear path send you unshielded control wire so make your own if you use them . keep in mind the dmm4 ac servo so thers more power and faster they a better value

thers 4 diferent control in the drive you can program.plus no dc power supply.just ac power.. they work with masso no problem . hope fully masso can keep up with the servo I don't know masso frequency out put

I would think heigh enough

The pricing of the Teknic clearpath servos and the DMM servos is very close to each other. Once you buy all the cables and accessories needed, the price is very close to the same. Price is not an issue between the two.

As for being a "true AC servo", it depends on what you mean. Both the Clearpath and DMM motors themselves run off of DC power. The Clearpath have built in drivers in the motors and only requires a separate 75v power supply. The DMM DYN2 has a driver and separate power supply. The DMM DYN4 has the power supply built into the driver.

As for the 5 volt step and direction signal being "outside the controller", the DMM DYN4 has a built in 24 volt power supply and they use a 2K resistor built into the cable to reduce the 24 volt down to 5 volt for the step and direction signals. So the 24v to 5v is not inside the driver, it is in the cable.

The Clearpath cables are not shielded. Clearpath says, All ClearPath I/O signals are electrically isolated from ClearPath s DC power input and motor output circuits, as well as from the motor case. This design feature helps to ensure that control signals aren t compromised by induced currents from the motor, power supply, or internal PWM.

I've never heard of anyone having EMI problems with the Clearpath cables so I wouldn't think that is an issue as with what Clearpath has stated above.

As for speed, one has to consider that into the built design. Most of the time, speed is limited by the design/construction of the carriage. Most homebrew builds or conversions can't handle the high speeds very well. So in real world conditions, both the Clearpath and DMM are plenty fast most any machine. Motor tuning is more important as to be able to get more usable speed. Both the Clearpath and DMM are tunable for better ramping and acceleration/deceleration.

 

[machinedude]

DMM 750 Watt motors I have are rated at 5,000 rpm's that's what made me go with them. i'm running them with a DYN4 drive on single phase 240V, only the smaller motors run on DC voltage. the 750 watt motor's i'm using can go either way but you don't get 5,000 rpm from them on DC and if you run them on 110v you will get far less as well. more speed means higher feed rates and high rapid rates. hooked to Masso I am getting roughly 650 imp with my set up. can't say at this point how much I can push the acceleration since i'm still building the actual machine. But I am using linear rails and ball screws so i'm not concerned about things moving fast. i'm more concerned about momentum with the weight of things i'm pushing and pulling around. so 650 imp may not ever happen in reality since to get up to speed and slow back down may take more space than what I am working within.

Clear path would be a perfect example of the grey area of claims of a servo system when in reality it's more of a hybrid system. I was not that impressed with them honestly. I think a dead give away is what the motor's are rated at speed wise and the torque speed curve data sheets. if the motor is rated at around 1,200 at best conditions then you are probably dealing with a hybrid system if they claim it to be a servo. and to go a step further if the holding torque is only stable over a small spread of several hundred rpm's it's probably a hybrid system too. I personally would never go with them but that's just my opinion on them. they have some good points but I think the short comings are far greater at their price point.

 

[testyourdesign]

650 ipm is blazingly fast. I am happy at under 200 ipm in my shop. You have to have a very heavy duty machine for those speeds.

In case anybody is interested in learning more about clearpath motors check out Franco's latest video on YouTube. He explains the clearpath setup process in detail. He went with very small clearpath motors on his benchtop cnc router.

I hope to do the same on my scratch built cnc router using my second Masso controller in the future.

Cheers, Stephen Brown

 

[rod]

hey guys,

got a 750W servo on the way from DLL, cost me in the order of $1500 AUD including a 100:1 reduction gearbox, and all the stuff i need to plug and play.

it took a few emails and due to the time lag it has taken about a week to get things organised.

My tips for the next guy,

Firstly I found the torque and speed needed to drive my machine. in my case it was a matter of finding a similar machine and copying the motor specs.

once I had this, just googled DLL and found the sales email. I told the guy what i was doing, he organised the rest including diagrams to wire to masso.

supper easy so far,

now to order the Masso...

 

[machinedude]

Quote from Rod on June 6, 2019, 10:08 pm

hey guys,

got a 750W servo on the way from DLL, cost me in the order of $1500 AUD including a 100:1 reduction gearbox, and all the stuff i need to plug and play.

it took a few emails and due to the time lag it has taken about a week to get things organised.

My tips for the next guy,

Firstly I found the torque and speed needed to drive my machine. in my case it was a matter of finding a similar machine and copying the motor specs.

once I had this, just googled DLL and found the sales email. I told the guy what i was doing, he organised the rest including diagrams to wire to masso.

supper easy so far,

now to order the Masso...

@rod

Did you mean to say DMM? I've never heard of DLL ? If you meant DMM you will need some male DB25 cords to run from the Drive to the Masso for your step and direction signals if your using the DYN4 drives. The other drives may still need them as well but I have not looked over those since I am not using them. the one I have linked works well since the individual wires are color coded. color coded wires make pin identification a heck of a lot easier.

you can just plug one end into the Drive and cut one end off and strip back the wires you need so you can make your connections and trim the rest back to the cable casing and shrink wrap to neaten everything back up. you may be able to make two from one cable depending on how far you need to run things?

the PDF file is the info on the individual colored wires for the cable.

AK401-2 Assmann WSW Components | Cable Assemblies | DigiKey

Order today, ships today. AK401-2 – D-Sub Cable Assembly DB25 Beige, Individual (Round) 6.56' (2.00m) Plug, Male Pins to Plug, Male Pins Shielded from Assmann WSW Components. Pricing and Availability on millions of electronic components from Digi-Key Electronics.

www.digikey.com

 

[rod]

yes, sorry DMM, and DYN4, I believe I have the cord coming from DMM. but time will tell!

 

[machinedude]

Quote from Rod on June 11, 2019, 2:29 am

yes, sorry DMM, and DYN4, I believe I have the cord coming from DMM. but time will tell!

the cables they provided are for the connection between the motors and drives one is for the motor to drive and the other is for the encoder to the drive. the db25 cables I listed are how you breakout your step and direction pins to connect to the masso. one end will plug into the db 25 port on the drive and the other end gets cut off so you can attach some connectors to the pins that are your step and direction pins. hold onto the link just in case I do think you will need those cables eventually.