Hello,

I have a cnc machine with a damaged control (PLC, control panel, all is damaged), but the Siemens 611 hardware looks ok and they power up.

I am looking for information to know if it is possible to control the drives (in this case they are 2 axis + spindle) with another controller.

I have experience in control drives with standard IO signals and analog +-10V for speed setpoint. With this post I am looking for information to know if it is also possible to control the 611 drives in a similar way. Any information is welcome.

Thank you

Are those 611 U or 611 D?

Please provide control card & LT module MLFB numbers.

Hello,

Yes, you can use those infeed modules & drives. These are 611A analoge type, which works on DI/DO & with 10 V analog set point. Please download the below manual which will help you to understand the commissioning of this system. But for this you need servo motors with tacho or resolver feedback & not digital encoder. 

SIMODRIVE 611 analog, Transistor PWM Inverters for AC Feed Drives and AC Main Spindle Drives.

HTH.

Those are great news!

Regarding the type of feedback devices, no problem at all as the machine where the drives are installed still have the original motors, even connected to the drives. Drives are then also tuned to the motors.

For what I understood, you are almost sure that the drives will accept a velocity set point in a form of a analog signal (-10 to 10VDC). It should also have In/Out like Enable, Drive OK, etc ... ?

I read before documentation of the drives (I think not that one that you recommended) and I saw that the drives use communication of type profibus. If Profibus is mandatory for using the drives then I cannot use them (no hardware available to generate the profibus commands), but if the drives accept the analog signals and have IO for controlling the drives then I will certainly have a working system.

Thank you once again,

John 

Hello,

Its nice to hear original motors are with machine. But the main worry is spares & service support of drive & motors. However, please go thru attached manuals, you will have detail idea. Profibus is optional. Basically it works with DI/DO & Analog set point.

 Can you take pictures of your drive--I don't think they can use profibus, as your post parts# showing they are 611A , on drive side there is no possible insert any profibus option control element

if profibus control in the original PLC rack . it will be no affect to you to change it to what you like +/-10V analoge control , the enabling signals are on the terminal --they are 63,64 on E/R module ;

663,65 on VSH (feed module); and 663,65,81 on spindle control check the manual PISCEAN2010 post here. 

AutoGen_7380581

Those are great news!

Regarding the type of feedback devices, no problem at all as the machine where the drives are installed still have the original motors, even connected to the drives. Drives are then also tuned to the motors.

For what I understood, you are almost sure that the drives will accept a velocity set point in a form of a analog signal (-10 to 10VDC). It should also have In/Out like Enable, Drive OK, etc ... ?

I read before documentation of the drives (I think not that one that you recommended) and I saw that the drives use communication of type profibus. If Profibus is mandatory for using the drives then I cannot use them (no hardware available to generate the profibus commands), but if the drives accept the analog signals and have IO for controlling the drives then I will certainly have a working system.

Thank you once again,

John 

Thank you for the reply (both)

We will try to fix the machine in the next month so we will read as best we can the manual and report back as the retrofit evolves.

In this case we have a CNC lathe with C axis, spindle, 2 axis and a live tooling. Let's see how this will turn out.

John

You are welcome for any questions in your m/c recovery work. and if you need some help --SW or HW

I think I can help for most of them. Google "AUTOMATION_U_TRUST" --you will find they have a same Logo with my logo here. --it has been more than 25 years Siemens Automation experences --special for CNC and drives.

After many days of work I was able to make all axis work, including spindle. Spindle worked good for about a week, and with analog voltage at 10V I could get about 3000rpm that is the max speed of the original manufacturer.

Now I have a big problem: the spindle does not pass of 560-580 rpm. I checked the analog voltage and it is correct, but the spindle does not respond to it. It does respond to it only until about the max speed that the spindle reaches. This is: If I ask 100rpm on the controller the spindle rotates at that speed, 400 is rotates at 400, but for example if I ask 1000, it only rotates at 480. The controller outputs 10V on the analog output to try to make the voltage higher to increase speed, but even with 10V it does not reach the desired output.

I have sure that the drive is not set up for C axis mode.

Looking at the parameters on the drive, I can see that for all asked speeds larger than 580rpm the parameter parameter P-004 is at 100 (drive utilization) - maybe this is 100% load? For all less than 580 I get much lower values in P-004, like 8 or 10 that seams correct if the parameter is for load.

I also checked the main motor, and I measured the resistance in the terminals, I get about 0.1-0.3 ohms. This is low, but the motor is large. The values are correct?

After so much work making the machine live again, this... very disappointing.

I also took a picture of the P-000 (status), with the drive running at about 100 rpm. For a larger speed the status is the same, but the parameters P-001 and P-002 (requested speed and actual speed) do not match, that means that the asked speed is correct and also means that the measurement of the actual speed is also correct (but speed is not !)

Any recommendations are welcome.

Thank you and have a good Christmas.