Configuring 5i20 files for lathe

[visky]

I am going to use mesa 5i20 card and 7i33T analog servo amp.interface (+/-10V) card ,7i37T io (16input and 8 output).

I need help to config default configuration files with 3 axis to two axis lathe.
X and Z axis

Encoders are 2500lines diferential. Spindle is 5mm/rev pitch.
resolution is 1000pulses/mm.

Help me modify ini file for lathe machine.

[acondit]

visky,

Do you still need help with this?

Alan

[visky]

I didn't work on it few weeks. Now i starded to finished it. I allredy connect Z axis encoder and it works

There is an enable output signal ( +5V ) , this signal i would use to enable contactors for motor amplifiers.

If i would have a problems ,i would post them.

[visky]

X and Z axes are moving. I have got a small ( big) problem with PID configurations. Because these are analog drivers when i enable them they are slowly,slowly rotor moveing (: .What i have to do and probe to hold motor and it wount rotate any more? What to do with PID, gain etc.

Another question:

I am useing only two analog output 0 and 2. Can i configure 1 ( Y axis) to be a spindle +/-10V control? I will have frequency inverter for 3 phase AC motor which accept -10 to +10 analog input .

[Ray Henry]

Originally Posted by visky X and Z axes are moving. I have got a small ( big) problem with PID configurations. Because these are analog drivers when i enable them they are slowly,slowly rotor moveing (: .What i have to do and probe to hold motor and it wount rotate any more? What to do with PID, gain etc.

There are quite a few parts to answering this. If the motors rotate slowly as soon as the amps are enabled, you probably have to tune these amps before you start with EMC2 tuning. Many drives have what they call a bias or zero adjust to allow you to stop rotation when no motion signal is applied and the position feedback loop is open. Turning this pot should let the motor sit without rotating. I tend to turn this after I've shorted between the velocity command screws or pins.

There is a brief introduction to EMC2 PID tuning in the 2.2.6 Integrator Manual about page 192. If you have the current EMC2 release on your PC there it will be available under the Applications -> CNC menu. The actual numbers for P, I, D, FF0, FF1, and FF2 will depend upon the nature of the drive amp and it's control mode.

The EMC2 wiki also has a page available at Tuning_EMC2/HAL_PID_Loops. There are several references there that will help.

There are also IRC logs chat-2004-09-26. and chat-2004-09-19

The EMC2 tools that I use for servo tuning include Halscope, Calibration, and a graphical interface. If you are using the AXIS GUI you'll find these tools under the Machine menu. You can read some about these tools in the manuals available with the release.

[visky]

I have got problems with PID configuration. In the integrator manual i notice that first i have to tune P until it starts to oscilate. Ok,I did that. Than write critical gain Kc and oscillation period Pc. Where can i see this ?

Is it possible to see a graph in halscope -PID tunnings? If so, how?

Write me yours PID tunnings parameters and i would check it on my machine.

My drivers are configured in "IR compensation mode". In this mode they have high torque at 0 speed and they can be used for open loop or closed loop mode.

[Big John T]

visky, if your using axis there is a servo configuration window where you can test your settings. It is in Machine/Configuration or something like that.

John

[Ray Henry]

In the AXIS display it is called calibration. Both TK graphical interfaces also allow access to the same servo calibration display. You may have to look around in the menus but it should be under Settings.

Servo tuning is not a trivial task and PID values that I set up for something like a Mesa 100 watt driver card will be far different from those I'd set up for a Mesa analog system. Most every setup is unique. Often the tuning parameters will be different from one motor to another on the same machine.

The tuning formula suggested on that Integrator Manual page is only one of many. Each will give different numbers. My own tendency is to tune by eye and ear rather than formula. Once the motor oscillates a bit, add a little I, start with 1 and see if it reduces the speed of the hunting. If so add a bit more. When you get it settled down, you'll find that it will be a bit slow accelerating so you'll need to add D. Eventually you'll want to add a bit of FF as well but you can see the effect of these variables better with halscope.

I start halscope, connect it's sweep to the servo thread, and watch PID.#.error and axis.#.joint-pos-fb. The feedback will sweep quite a range so I tend to command relatively short motions using MDI. By separating the position of the two sweeps I can see the relationship between error and position.

Change only one variable at a time and make a note of the old value, the new value, and the effect of the change. That servo configuration page will allow you to switch between values quickly with the Test and Cancel buttons if the motor misbehaves.

I've been known to spend hours playing with PID tuning so don't expect to find perfect numbers on a first try.