qchen3

For a motion axis with limited position feedback resolution, its original position feedback needs to be explicitly corrected and smoothed out instead of using standard filters provided by Power PMAC. What is a good implementation approach at each servo sampling cycle so that this corrected position can be used for (1) Its own closed loop servo control (2) Master command for a slaved motion axis.

(1) What is the convertion factor from the value of to the voltage value? - The manual indicate is a 24-bit ADC - However, our measurment show value of ~1.5e9 (peak-to-peak). - Is for the differential signal of +/-sin or +/-cos? (2) What is the converation factor from voltage value to the value of ? - The manual indicates AdcOffset is 32-bit value - Is it for the voltage range of 1?

According to the manual: Gate3.Chan[j].AdcOffset[k] elements specify the bias-correction values that are automatically added to the 32-bit registers for the primary “encoder” ADC data values for the channel before the IC performs subsequent arctangent and sum-of-squares calculations. Question: (1) As a result, this AdcOffset is NOT used to make any correction in the zero-crossing detection of sin/cos signal, right? (2) What is the differerence between this register and EncTable[n].CosBias/EncTable[n].SinBias ?

If the sinusoidal encoder signals have some problems in term of the DC offset, phase offset, and amplitude. Is it possible to tune the signal through the axis interface board ACC-24E3 in the Power PMAC system? I have not been able to find this information in the Hardware Reference. It will be useful to have some hint. THANKS!

I am using OS: Window 7 Professional IDE: 1.3.1.46 Firmware: 1.3.0.0

The statement on Gate3.Chan[j].TimerMode in the User's Manual (page 473) is what exactly confused me: (1) " All 3 elements are unsigned 32-bit integer values, in units of 1/4096 of a count of the encoder. That is, they have 20 bits of full-count information, and 12 bits of fractional-count information." (2) "If saved setup element Gate3.Chan[j].TimerMode is set to its default value of 0, “hardware 1/T” count extension is enabled for the channel to calculate an estimated fractional-count value every SCLK cycle. The IC can then compare the combined whole-count and fractional-count value against the values in the compare registers, which have 24 bits of whole-count data and 8 bits of fractional data." Which fractional-counts is used then: 12 bits or 8 bits? Initially, I thought 12bits fractional-counts is for sinusoidal encoder, 8bits is for quadrature encoder. Since a sinusoidal encoder is used for my case (Gate3.Chan[j].AtanEna=1), I thought the setting of TimerMode does not matter.

Our usage of Power PMAC IDE constantly generates user interface error in the Position Window with the disappearance of the text content and appearance of a big red cross. What is causing this problem?

For the hardware position compare function in the Power PMAC, as stated in the manual, (1) The CompA and CompB specify the raw encoder encoder position at which a position-compare event will take place. It is in the units of 1/4096 of a count of the encoder. (2) When the instantaneous encoder position matches that of the preset CompA & CompB registers, the “EQU” compare digital output is toggled. This function is executed in hardware. The question is: If a sin/cos encoder is used, is the 1/4096 sub counts generated in hardware? If not, then the execution still has the software intervention since the instantaneous encoder feedback is generated in software. The reason to ask this question is because we have observed significant amount of “EQU” output pulse jitter at the constant velocity motion condition. The amount of position error in our motion system only accounts for small portion of this jitter. We need to find out the main contribution factor.

The reply from Sina showing the solution to start a background C application from motion program/script PLC. In a second scenario: If I need to disable such C application in the mid of execution, what is the command to be released in the script PLC?

There are two threads on preventing Background C program from being executed after a build&download by properly configuing the property. My question: How to start the program after that?