How to disable low voltage fault on GPL PWM drives with Acc24E3 (Enhanced Mode)

[kmonroe023]

What is the proper way to disable low voltage faults on a GPL PWM drive being controlled by an Acc24E3 card? The drive is being supplied with 48VDC.

 

On a PPmac with the E2 card I ran the following PLC code at start to disable the low voltage fault:

 

Gate1[5].AdcStrobe=$3FFFFF;

call timer(0.25);

Gate1[5].AdcStrobe=$c00003;

call timer(0.25);

Gate1[5].AdcStrobe=$a00023;

 

 

Running similiar code for the E3 card yielded some strange behavior, the motors did not seem to commutate correctly and/or had very little torque.

 

Gate3[1].AdcAmpStrobe=$3FFFFF;

call timer(0.25);

Gate3[1].AdcAmpStrobe=$c00003;

call timer(0.25);

Gate3[1].AdcAmpStrobe=$a00023;

 

I found that if I leave the AdcAmpStrobe at $a00023 the drives will run (the code above has been commented out of the program). However, there are occasional problems getting the motors on that card to run after a reset. What is the proper way to disable low voltage faults using the E3 card. I read through the GPL Drive manual and thought I understood the procedure when I got the motors running with the E2 card. What am I missing when applying the E3 card?

 

Thank you,

kmonroe

[Sina.Sattari]

Kmonroe023,

 

Please see the following table for proper strobe words for Geo Direct PWM drive mode settings. Please note that you have to set Gate3.AdcAmpCtrl register so the strobe word and ADC header bits are set at the same time.

 

The following table has been updated with correct settings (Jan 20, 2012. Sina Sattari)

 

Mode                    Gate1 Strobe Word (I7m06)       Gate3 Strobe Control (Gate3[i].AdcAmpCtrl)
----------------------- ------------------------------- -------------------------------------------
Default Mode            $3FFFFF                         $FFFFFC02
Enhanced Mode           $C00003                         $C0000204
Return IGBT Temp        $800003                         $80000204
Return Bus Voltage      $880003                         $88000204
Set shunt regulator
control for 120 VAC
input (3U042 only)      $A0000B                         $A0000A04
Set PWM control for
DC brush motors         $A00013                         $A0001204
Turn Line Monitor Off   $A00023                         $A0002204

[kmonroe023]

Hello Sina,

 

So, would the PLC code for the startup PLC look like this:

 

Gate3[1].AdcAmpCtrl=$FFFFFC02;

call timer(0.25);

Gate3[1].AdcAmpCtrl=$c0000304;

call timer(0.25);

Gate3[1].AdcAmpCtrl=$a0002304;

 

Setting the strobe words makes sense, but I don't understand why the ADC header bits need to change from 2 to 4. Are there delays in using the extended mode that need to be accounted for?

 

Thanks!

[Sina.Sattari]

Hi Kmonroe023

 

Yes, you are correct about the PLC.

 

The reason for change from 2 to 4 header bits relies in flexibility of Gate3 compared to Gate1. In Gate1 strobe word, setting bit 0 of the strobe word to 1 tells the Gate that there are up to 4 header bits expected on ADC data and these bits are rolled over to lower 4 bits of the ADC data such that the MSB of ADC data is placed in bit 23 of ADC feedback register. If we expect less than 4 header bits, in case of Geo Direct PWM we expect 2, we set the higher bits of ADC strobe word to 0 which delays the strobe for that many bits.

 

As you can see for default case, Gate1 strobe of $3FFFFF means expecting 2 header bits and the rest of the bits for strobe word is held high (bit0 is 1: expect up to 4 header bits; bits 23 and 22 are 0: (4-2) header bits are expected), in Gate3 we do the same by setting the strobe word to $FFFFFC (all bits high except the last two where we want the line to be held low until next strobe cycle) and header bits to 2.

 

For enhanced mode of the Geo Direct PWM drives, both bit 23 and bit 0 are set to 1, which means there are 4 header bits as expected by Gate1 so the Gate3 header bits are set based upon this principal.

 

[Sina.Sattari]

Please make sure to use the following settings in order to use enhanced mode features of the Geo Direct PWM Drives:

 

 

1. Make sure Motor[x].PhaseCtrl=4

2. Make sure Gate3.Chan[j].PackInData=0

3. Make sure Gate3.Chan[j].PackOutData=0

4. Use the following table for enhanced mode strobes and make sure to leave the unit in enhanced mode.

 

Mode                    Gate1 Strobe Word (I7m06)       Gate3 Strobe Control (Gate3[i].AdcAmpCtrl)
----------------------- ------------------------------- -------------------------------------------
Default Mode            $3FFFFF                         $FFFFFC02
Enhanced Mode           $C00003                         $C0000204
Return IGBT Temp        $800003                         $80000204
Return Bus Voltage      $880003                         $88000204
Set shunt regulator
control for 120 VAC
input (3U042 only)      $A0000B                         $A0000A04
Set PWM control for
DC brush motors         $A00013                         $A0001204
Turn Line Monitor Off   $A00023                         $A0002204