[Coordinate systems D-variables]

Thank you very much, curtwilson.

PREAD is the exact command I was searching for.

[Coordinate systems D-variables]

Hi,

 

Is it possible to configure a global variable from communication-thread D-variables?

 

I cannot access the position readback of virtual axes individually from a PLC file, and I don't know why. I just want to map a readback position to a Q variable, but it is not that easy from a PLC file...

 

The only thing I want is the numerical response for one axis, not string for all axes like the output for "&1p" command.

 

Example:

 

&1p

X111 Y222 // string output with all axes set in D0 mask

&2p

X333 Y444

 

I can access the desired values with commands like:

 

&1D // Apply "CS1 environment" to D-variables

X111 Y222

D6 // Query CS1 axis X position

111 // this is the output I want

D7 // Query CS1 axis Y position

222 // this is the output I want

&2D;D7 // Change D-variables to CS2 environment; query for CS2 Y position

X333 Y444 // first command output (undesired)

444 //second command output (desired)

 

But these commands only work from communications threads / scripts other than PLC files.

So I tried to access from PLC file the D-variables from coordinate systems and PLCs, but these are different domains.

 

What I am missing? How can I access these values from PLC?

 

Controller: Power Brick LV

 

 

Best regards,

Marcelo Moraes

[from Turbo Pmac2 to Geo Brick]

If you can reduce the external inductance to a value of 1mH, you can achieve the highest capability of Geo Brick LV.

 

Hi Sina,

 

I am facing the same problem with PWM amplifier + low-inductance motor.

 

Motor:

Inductance line-line = 1.7 mH

Resistance (25 deg Celsius) line-line = 4.4 ohms

 

tau_sec = 1.7e-3 / 4.4 = 386.36 usec => minimum_PWM_f ~ 8 kHz

 

The PWM frequency is set to 20 kHz (maximum recomended value for my amplifier), and the open-loop noise (#1out0) is too big.

We tried to supress the noise by adding 1 mH inductance in series, which attenuated it but didn't achieved our stability spec. Then we tried bigger inductance values, but it didn't work very well.

 

How did you calculate the optimum value of series inductance?

What would be the optimal value for my scenario?

 

Controller: Power Brick LV (5 A / 15 A amplifier)

 

 

Regards,

Marcelo Moraes