Editing Using stepping motor with IONI

Using stepping motor with [[IONI]] drive is possible in three ways:

;Mode1 - Open loop (no encoder)
:This is the traditional stepping motor drive method. Will achieve highest speed and is easily configurable but there is no feedback, so if motor stalls/loses synchronism, the absolute position will be unknown before referencing/homing.
;Mode 2 - Closed loop (with encoder feedback)
:This is open loop mode combined with encoder feedback. The advantages are that drive can detect loss of synchronism and restore to commanded position with ''clear faults'' command. May be used also with linear encoder to enhance system accuracy. 
;Mode 3 - Servo (with encoder feedback)
:In this mode, a stepping motor is used as high pole count brushless servo motor. In this mode, motor efficiency is high (no current if no load) and motor do not lose synchronism. However, motor speed is limited by back EMF of motor and typically can achieve lower top speed than the other modes.

In the modes 1 and 2 stepper is driven with constant current drive and the motion produced by adjusting phase angle (traditional stepper drive method). In the mode 1 phase angle is controlled directly by [[setpoint]] trajectory and in mode 2 it is controlled by encoder based feedback loop. In the mode 3 motor current is controlled by torque controller (from zero to peak current limit) while phase angle is synchronized to rotor angle by the help of encoder. Mode 3 is similar to servo motor control ([[Signal path of motor drive|more details]]).

==Setting up open loop mode 1==
In open loop mode (traditional stepper motor mode) uses smooth microstepping of 128 microsteps per one full step. Resolution may be optionally reduced by increasing the {{param|MUL}} value.

In this mode, drive emulates encoder internally and some tuning parameters need to be set to allow operation:
;[[MT]] Motor type
:Stepping motor
;[[FBD]] Feedback device
:None
;[[FBI]] Invert feedback direction
:Unticked
;[[FBR]] Feedback device resolution
:6400 (this is the emulated encoder resolution, 6400 PPR = 25600 steps/rev)
;[[MCC]] Motor continuous current
:This is the resting current when motor stands still. Drive will switch to this after 0.5 seconds of standing still.
;[[MMC]] Motor peak current limit
:This is the motor rated current that is used when motor is rotating.
;[[MR]] Motor coil resistance
:See motor datasheet or if not known, start with low values such as 1 ohm
;[[ML]] Motor coil inductance
:See motor datasheet or if not known, start with low values such as 1 mH
;[[CM]] Control mode
:Set to Position control (typical) or Velocity control mode
;[[KVP]] Velocity P gain
:0
;[[KVI]] Velocity I gain
:700
;[[AFF]] and [[VFF]]
:0
;[[KPP]] Position P gain
:10000
;[[PFF]] Position feed-forward gain
:100%
;[[FEV]] Over speed fault
:1000
;[[FPT]] and [[FVT]] fault limits
:1000

Other settings are not critical and can be configured as desired (such as acceleration and velocity limits). If setpoint scaling is 1:1 ([[MUL]]=[[DIV]]), then this mode yields resolution of 25600 steps/revolution. If reduction of resolution is required, then adjust scaling accordingly (if scaling is set above 4:1, then try also Setpoint smoothing [[CIS]]).
{{tip|Use Granity's ''Measure resistance & inductance'' button to automatically set MR and ML}}

{{download|To save time, you may load [[Media:IONIStepperSettingsTemplate3.drc|this template settings file]] to drive. '''Usage:''' connect to the drive with Granity, and click ''Load settings from file''. After loading the file, just set motor current limits MMC and MCC to match your motor. After saving & restarting drive, use ''Measure resistance & inductance'' button to automatically set MR and ML. }}


'''NOTE:''' these values and settings apply from '''firmware version 1.5.2''' (1096). For older firmware version settings, see:
* [http://granitedevices.com/w/index.php?title=Using_stepping_motor_with_IONI&oldid=5109 Version 1.2.1 - 1.5.1]
* [http://granitedevices.com/w/index.php?title=Using_stepping_motor_with_IONI&oldid=4026 Version 1.2.0 and earlier]

==Setting up closed loop mode 2==
In this mode, follow parametrization of open loop mode (mode 1) except:
;[[FBD]] Feedback device
:Choose your feedback device (other than None)
;[[FBI]] Invert feedback direction
:Try both settings and choose the one with stability
;[[FBR]] Feedback device resolution
:Set your feedback device resolution
;[[KVI]] and [[KPP]]
:Tune KVI, VFF, and KPP values (and possibly other gains if non-zero) to have nice response
;[[FMO]] Motion fault limit
:Set non-zero value (perhaps 100-1000) to cause a fault state when motor stalls

{{tip|In this mode it might give best response when KVI has been set very low value and Velocity feed-forward VFF tuned to non-zero value. As starting values you may try the ones mentioned in the example below.}}
{{tip|One practical system we successfully configured in Mode 2 had following equipment: a typical 200 step/rev stepper, 1 mm/rev lead screw and a 0.1 µm/count resolution linear encoder, we found following well behaving parameters: KVI 2, VFF 40, KPP 150, PFF 100. Especially VFF value should is subject to change significantly when system resolution changes (i.e. encoder or lead screw).}}
==Setting up servo mode 3==
To set-up stepper as servo motor, just follow the [[IONI & IONICUBE user guide]] and consider the stepper motor as servo motor. For a typical 1.8 degree/step two-phase stepping motor the correct motor type parameters are:
;[[MT]] Motor type
:2 Phase AC or BLDC
;[[MPC]] Pole count
:100           

== Optional: reducing motor vibration and noise ==
IONI firmware 1.5.2 and later supports reduction of stepping motor vibration and noise by the means of parameters TRF1, TRA1, TRF2, and TRA2.

[[File:Stepperlinearizeparams.png]]

=== Usage ===
For typical 2-phase (4, 6 or 8 wire) stepper it is recommended to try TRF1 of Sin(4x). 
# To adjust TRA1 to optimum value, make motor move slowly by setting up test stimulus from Granity Testing page and setting low values into acceleration and velocity limits (CAL and CVL). For example as test stimulus settings, try TSP1=10000, TSD1=0.5, TSP2=0, TSD2=0.5, CAL=1, CVL=1000. 
# While motor is running slowly back and forth, adjust TRA1 until the motor vibration and noise is minimized.
# Some motors also benefit from using third harmonic of this setting, Sin(12x) which may be enabled by setting it as TRF2 and doing same procedure for finding the optimum TRA2 value.
'''Note:''' some motors do not receive significant benefit of these settings. In such case, it's recommended to leave these settings disabled (TRF1 & TRF2 = None and TRA1 & TRA2 = 0) to avoid making the smoothness actually worse.