Dear Sir, 

I have not had any experience with DC Drives and motors. However, Im assigned to replace the control of a flying saw cutter machine. I have searched a lot and read almost all of the threads posted helping ppl getting along with that. 

Since I have used the s7tech PLC with sinamics s120 cu320-2 to control the motion of an axes, i thought i would do the same with the sinamics DCM but it seems much tougher than wt i thought.

Can you please help me solving the below Issue:

1- flying saw for steel pipe mill, its carriage's motor is as follows,

* Power=45KW

*rpm= 1250

*Ua= 400 V

*Ia= 128 A

Uf=220 V

If= 5.4 A

2- Spead ranges ( 30 mm/Min - 90mm/Min)

3- There is a flying wheel ( with Encoder" leading Axis") to give the length and speed which will decide the movement of the carriage to sync with line speed and cut to length.

4- There is an encoder on the motor as well.

In this assignment i have to replace the whole control except the motor. Im kinda lost and dun know where to point as not much of info i found online.

Anyway, decided to use the sinamics DCM of 400V, 210 A, 4Q with either s7-tech, cu320-2 and DCM( which seem not possible) or with D425 and DCM.

Can anyone kindly point me to the right path where i can build this system up without risk.

Thanks A lot 

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Split from Simotion I-Device Configuration with Sinamics DCM.

If you have no experience with flying saws, get ready for a difficult time.  These applications are very difficult.

I use a D435 for mine, as I found the D425 to be too slow.  Since the D4x5's do not support DCM, you can also use a C240. If you want to interface to a DCM, try to get a PROFINET version (I have not used a DC drive in 20 years, so I do not know much about them).  Your D4x5 should be PROFINET also.  You can use the SERVO_FAST loop for communication.

There is a standard application that Siemens developed for flying saws using SIMOTION, you may want to look at that.  I wrote my own, as it did not work the way I wanted it to.  There are several strategies, one common way is to use Camming.  I use gearing.

Step 1. Enable Gearing, wait for synchronization
Step 2. Enable torque limiting when clamps close
Step 3. Disable torque limiting when clamps open
Step 4. Disable gearing
Step 5. Return to Start Position

You will want one real axis for your line encoder as a master and one Virtual axis to simulate the line encoder for testing.

This should be a separate topic.

Hello.

Look here:

Linear flying saw application with DCB extension

SINAMICS OA Application OALINK V1.2

KSN

Hello.

Look here:

Linear flying saw application with DCB extension

SINAMICS OA Application OALINK V1.2

 Hi KSN

I have gone through OA, from that I came to know that a connection between cu320-2 and advance CUD is possible. Hence, Im thinking of using an s7tech (317t-for PLC functionality) with cu320-2( as motion controller)  to handle the control of a flying saw application Via the OALINK from cu320-2 to the Advanced CUD of the sinamics DCM (as the carriage is being driven by a 45KW DC motor.

will this controller satisfy this application?

appreciate your help and advice.

Jeff Casagrande

If you have no experience with flying saws, get ready for a difficult time.  These applications are very difficult.

I use a D435 for mine, as I found the D425 to be too slow.  Since the D4x5's do not support DCM, you can also use a C240. If you want to interface to a DCM, try to get a PROFINET version (I have not used a DC drive in 20 years, so I do not know much about them).  Your D4x5 should be PROFINET also.  You can use the SERVO_FAST loop for communication.

There is a standard application that Siemens developed for flying saws using SIMOTION, you may want to look at that.  I wrote my own, as it did not work the way I wanted it to.  There are several strategies, one common way is to use Camming.  I use gearing.

Step 1. Enable Gearing, wait for synchronization
Step 2. Enable torque limiting when clamps close
Step 3. Disable torque limiting when clamps open
Step 4. Disable gearing
Step 5. Return to Start Position

You will want one real axis for your line encoder as a master and one Virtual axis to simulate the line encoder for testing.

This should be a separate topic.

 Mr. Jeff 

thanks for the advice, and Im really determent to get this task done through this difficult time.

Now since u mentioned that the d425 away too slow for the application, what about the cu320-2, i have used it before for a wrapper line and it worked perfectly accurate. but it was not on the fly, as the line used stop for each punch and cut.

It would dramatically change from difficult to easy  task if this would work with s7-t-cu320-2-OA-Advance CUD.

thanks for your kind advice and looking forward for more.

Mori

The critical component in cut to length is the IPO (reference generation) cycle.  This is where all of your position regulators are running.

At 90 mpm, you are going 1500 mm/sec.  My experience with D425 and I believe for TCPU (I don't know this for a fact) is the fastest IPO cycle is 2ms.  This means every IPO cycle, you are traveling 3mm.  I don't know what your cut tolerance is, but that is quite a bit.  My written spec is usually +/- 2mm and my goad is +/- 1.

Will it work with TCPU?  Yes.  Will it work well?  Depends on your performance requirement.

Couple of years ago I had to follow up a flight saw cutting pipe mill max speed 60 meter / minute and I was forced using a T-CPU (customer choose). The measuring wheel is drive CliQ hardwired and the encoder is on the same CU of the main cutting share drive.

The result is not very bad even I preferred Simotion as hardware. The new sync. position of the pipe incoming come from the real measure and the last set point. With the tech.FB this can be done internal on the servo side and the accuracy is not affected with the communication delay with the PLC.

Anyway if I have to choose the hardware I always prefer Simotion because of the fastest cycle compared with PLC even the accuracy depending very much from the mechanic side .....

pigroplc

pigroplc

Couple of years ago I had to follow up a flight saw cutting pipe mill max speed 60 meter / minute and I was forced using a T-CPU (customer choose). The measuring wheel is drive CliQ hardwired and the encoder is on the same CU of the main cutting share drive.

The result is not very bad even I preferred Simotion as hardware. The new sync. position of the pipe incoming come from the real measure and the last set point. With the tech.FB this can be done internal on the servo side and the accuracy is not affected with the communication delay with the PLC.

Anyway if I have to choose the hardware I always prefer Simotion because of the fastest cycle compared with PLC even the accuracy depending very much from the mechanic side .....

pigroplc

 Dear Pigroplc

Had you used a DC drive(SinamicDCM)  along with T-cpu and Drive CU?

as I want help figuring out whether or not this configuration would give good result with this particular  application. I mean using t-cpu(i.e 317-t with sinamics S120 technology control unit CU320-2 (technology blocks are to be used ) communicating via Profibus (12Mbit) and then using the OA application to connect this CU320-2 to the advance control unit CUD of the sinamic DCM dc drive for the DC motor that actuate the carriage  movement.

I think by you saying "not very bad" confused me a lot; as I could deduce that it could be bad but not very, Do you mean that it was not accurate enough? or it just did a good job which was acceptable? 

The accuracy or I can say the tolerance should not be above  -/+ 3 mm and the maximum speed should not be lower than 65 m/min

Appreciate you sharing your experience.

Thanks 

Mori

Mori,

I used a brushless motor 132Kw because the max cycle time considered defined an acceleration / deceleration for the back stroke up to 5,5 mt/sec2.

As you can figure out the accuracy is not depending on the brushless or not-brushless  motor because the gearing happens with a smooth dynamic. Effective the syncro point has been reached with motion start before the syncro point reach the shear. The syncro parameters for instance define that the cutting shear start the motion 200 mm before the syncro point passing and complete the synchronization within 400 mm. A good explanation is available online on the flying shear example.

Not bad for me means this: the accuracy when you are cutting pipes 6 to 12 meters long is not so easy to crosscheck. Also there is the problem to place the measuring tape in the correct way to match the length and the real result as tested in my project was more or less 1 mm compared with target.

Also takes a lot of importance any possible deviation of the pipe before the cut and possible vibration. This can be reduced only placing the measuring wheel closer as much as possible to the shear's home position.

Another point is the accuracy of the shears main drive gearing (motor-gearbox-pinion-rack) and torque reduction while is geared.

As you can see the discussion touch a lot of items and need long time to shear ....

pigroplc