Relation of L6470H Speed Related Parameters

[Sandhya S]

Posted on April 07, 2017 at 08:13

Hi,

      I am using L6470H with stm32f103 for past few months in our project. I have clarified the KVAL value relation with motor through online.I worked out all the commands for motor running given in the  datasheets. It's working fine. The motor mode no is: BH57SH56-2804A 

Motor Datasheet Link: 

http://bholanath.in/certificates-files/integrated-TDS/BH57SH56-2804A-ID.pdf

      My questions here is to upgrade my project , before I need to clarify few things related to speed. I tried to find out but I couldn't find the proper answer.

My questions are:

1. In datasheet, there are different speed parameters like SPEED,MAX_SPEED,MIN_SPEED,FS_SPD,INT_SPEED. Is there any one to one relations with these parameters. I do not have complete clarification with these parameters. So, Please guide me to get clarify these parameters  
2.  Is there any relation between steps value entering in these two parameters( MaxSpd_Steps_to_Par(steps) and MinSpd_Steps_to_Par(steps)) with Speed_Steps_to_Par(steps).
3. In the Run (DIR, SPD) command, I have passed the steps values in SPD through MinSpd() and Speed() parameters motor is working fine. But , Once I entered the speed values through MaxSpd and IntSpd motor is not running.Is there any particular reason for that?
4. What is the relation of INT_SPEED and FS_SPD for motor?
5.  In the dSPIN library code, the values mentioned in the parameters like L6470H_CONF_PARAM_MAX_SPEED (991.821), L6470H_CONF_PARAM_DEC (2008.164) etc., is there any particular formula to find those values? why because is that , I have changed the values in these parameters based on the maximum value given in the datasheet but motor having trouble to run in changed values. So please someone help me out to overcome this issue.

The dSPIN library code link: 

http://www.st.com/en/embedded-software/stsw-spin004.html

[Enrico Poli]

Posted on April 19, 2017 at 14:48

1. The parameters refers to two different blocks of the system.

   MAX_SPEED,MIN_SPEED 

   are linked to the 'motion engine', i.e. the part of the device in charge of generating the speed profile. These parameters should be adjusted according to the mechanics of your application. FS_SPD allows automatic switching between microstepping and full-step, I suggest to set it to the max in order to force the device always working in microstepping mode.

   INT_SPEED 

   is a part of the Voltage Mode compensation algorithm and depends on motor characteristics.
2. These are the library functions converting values expressed in [step/s] (full-steps, no microsteps. The system takes care of the internal microstepping resolution) and the respective register value (MAX_SPEED, MIN_SPEED, etc).
3. The Voltage Mode algorithm probably is not tuned properly. Use the SPINFamily software to estimate the configuration parameters. IMPORTANT: put a small load on the motor shaft; this will help damping the resonances.
4. See points 1 and 3
5. You can use the SPINFamily tool to set all these configurations