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GEOBRICK MACRO
#1
Hi,
Trying to increase my PWM Frequency for a system that has a geobrick, ACC24M-2A, ACC65M and 2xACC85M

Everything work fine using 8Khz Servo, 16 Khz Phase, 8Khz PWM clock settings from the settings suggested in the manual for the ACC85M.

My problem is that I have a DC motor on axis 8 of the geobrick with a small time constant and need to run the PWM > 30Khz.

I used the MACRO Controller excel sheet and the PMAC2 clock calculator and use the attached settings for I6800/I7000/I7100, I6801/I7001/I7101 and I6802/I7002/I7102 and all other settings in the excel sheet.

Each time I download the settings and reset the controller X:$6 bit 7 comes on Servo/Macro IC config. error.

Any ideas?

Thanks


Attached Files Image(s)
   

.pdf   MACRO Settings.pdf (Size: 12.77 KB / Downloads: 17)
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#2
What type of Geo Brick are you using? GBL? GBD? GBC? Please post the part number.
Sina Sattari
Hardware Engineering Manager
Delta Tau Data Systems, Inc.
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#3
(10-09-2013, 02:30 PM)Sina Wrote: What type of Geo Brick are you using? GBL? GBD? GBC? Please post the part number.

GBL8-C0-882-19D00050 with TSO
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#4
Based upon the documentation GBL8-C0-882-XXXXXXX has a maximum PWM frequency of 18kHz.

Based upon this maximum PWM frequency of 18KHz, the highest theoretical frequency for your phase could be 36kHz (2x18kHz) since the PWM command will be effective twice per PWM cycle (adjustment of rising edge and falling edge per cycle).
Sina Sattari
Hardware Engineering Manager
Delta Tau Data Systems, Inc.
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#5
(10-10-2013, 09:22 AM)Sina Wrote: Based upon the documentation GBL8-C0-882-XXXXXXX has a maximum PWM frequency of 18kHz.

Based upon this maximum PWM frequency of 18KHz, the highest theoretical frequency for your phase could be 36kHz (2x18kHz) since the PWM command will be effective twice per PWM cycle (adjustment of rising edge and falling edge per cycle).

If we get a faster CPU in the GEOBrick would this allow us to operate at a higher PWM frequency? What determines this? What documentation should I be looking at?
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#6
No, if you have locally commutated axes on that ASIC you cannot set the PWM frequency higher than 18KHz.

As for the Servo/MACRO IC config error, if that is still relevant, I would like to see the exact parameters which you have downloaded. Otherwise, you may just needed to do a save and a reset.
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#7
The PWM frequency is limited by the thermal properties of the IGBT power transistors in the Brick. The higher the frequency, the more heat they dissipate.

Can you add large chokes to the leads of the DC brush motor you are driving to reduce the current ripple in that motor?
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