Elmo DSP 402 User Manual

Page of 116
CANopen DSP 402 Implementation Guide 
 
MAN-CAN402IG (Ver. 1.2) 
 
 
64 
10: Position Control Function 
6062h: Position demand value in position units 
6063h: Position actual value in increments 
6064h: Position actual value 
6065h: Following error window 
6067h: Position window 
6068h: Position window time out 
60F4h: Following error actual value 
60FAh: Position control effort 
60FCh: Position demand value in increments 
10.1   General Information 
This chapter describes all parameters required for closed-loop position control. The 
control loop is fed with the position demand value as one of the outputs of the trajectory 
generator and with the output of the position detection unit (position actual value) as input 
parameters. The behavior of the control is influenced by the control parameters. Position 
control parameters (PI/P) may be set using the Composer Wizard during setup. 
To ensure that the physical limits of a drive are not exceeded, an absolute limit function 
is implemented for the position control effort. The Elmo drive implements a cascaded 
control loop in which the position control effort is a velocity demand value for the velocity 
control loop. For further information about tuning the position loop and using the 
Composer Wizard, refer to the 
SimplIQ
 Composer User Manual and the 
SimplIQ
 Software 
Manual
The following terms are used in this chapter: 
 
Following error: 
position actual value outside the allowed range of the following error window around a 
position demand value for longer than the following error timeout results in setting bit 13, 
following error, in the statusword
  The position following error calculates each cycle of the position control. The 
position demand value must be set lower than the setup value of the drive 
following error ER[3]. When the position following error exceeds ER[3], the 
motion aborts.  
 
Position reached: 
This function provides the option of defining a position range around a position 
demand value
 to be regarded as valid. If a drive position is within this area for a 
specified time — the position window time — the related control bit 10 target reached 
in the statusword is set. Bit 10 is reset to 0 when the motor is off. 
  The position range in the Elmo servo drive is limited to ±1 * 10
9
 regardless of the 
DSP 402 maximum range.