Structured Parameter - stPosPara
Structure of parameters related to positioning
|
Parameter |
Data type |
Description |
|---|---|---|
|
diPosDiffMax |
DINT |
Maximum allowed difference between planned and actual position. Range: 0...2147483647 Default value: 0 Scaling/Unit: inc Refer to detailed description below this table. |
|
diInPosWdow |
DINT |
Size of in-position window. Range: 0...2147483647 Default value: 50 Scaling/Unit: inc Refer to detailed description below this table. |
|
winPosTime |
WORD |
Time inside in-position window to consider positioning finished. Range: 0...65535 Default value: 200 Scaling/Unit: ms Refer to detailed description below this table. |
|
wPosFailTime |
WORD |
Time for positioning failure detection. Range: 0...65535 Default value: 2000 Scaling/Unit: ms Refer to detailed description below this table. |
|
rKpPos |
REAL |
Proportional gain of the position controller. Range: 0...3.4028e+38 Default value: 5 Refer to detailed description below this table. |
|
rKpFeedFwd |
REAL |
Feed forward gain of the position controller. Range: 0...3.4028e+38 Default value: 0 Refer to detailed description below this table. |
|
diLsPosFwdSw |
DINT |
Position of positive software limit switch. Range: -2147483648...+2147483647 Default value: 0 (limit switch inactive) Scaling/Unit: user units Refer to detailed description below this table. |
|
diLsPosRevSw |
DINT |
Position of negative software limit switch. Range: -2147483648...+2147483647 Default value: 0 (limit switch inactive) Scaling/Unit: user units Refer to detailed description below this table. |
The parameter is defined in encoder pulses. Drive running in closed loop motor control mode will allow for lower value of i_stPosPara.diPosDiffMax because it can follow the target speed more accurately. When the drive is running in open loop motor control mode, it is necessary to increase the value to help preventing alarms.
This parameter defines the required accuracy of positioning.
Positioning is considered successfully finished when the difference between the actual and target position of the axis is lower than i_stPosPara.diInPosWdow for the time defined by i_stPosPara.wInPosTime. The parameter i_stPosPara.diInPosWdow is defined in encoder pulses.
Excessively low value will cause reports of detected error on positioning.
Zero value disables the in-position window function. Target position is considered reached immediately after profile generator reaches the target position.
Positioning is considered successfully finished when the axis is inside i_stPosPara.diInPosWdow for at least the time defined by i_stPosPara.wInPosTime.
This parameter detects unsuccessfully positioning. The time starts running when the internal position/speed profile generator reaches the target position. If the positioning does not finish successfully within this time, an alarm is signaled.
The time must be long enough to allow for finishing of the positioning under normal conditions.
A higher value of this input will proportionally increase the output of the internal position controller. The parameter influences the reactivity of the axis and also the accuracy of positioning.
Start the commissioning with a low value (for example 5) and slowly increase to find the optimal setting. If the response of the axis is too slow and the position deviation is too great, the value of rKpPos is too low. If the axis starts to oscillate, the value is too high.
The value of proportional gain is internally compensated for encoder resolution (pulses per revolution). It is not necessary to change this value if an encoder with different resolution is used.
The value of applicable proportional gain depends also on the accuracy (lag) of position measurement and accuracy of the speed loop of used variable speed drive.
To allow setting considerably higher value of i_stPosPara.rKpPos and achieving a higher level of accuracy, proceed as follows:
oRun the positioning in a task without short execution period.
oTransfer information about axis position via a low-latency fieldbus communication interface.
oConfigure the variable speed drive closed loop motor control mode.
Changes of the parameter value are taken into account immediately.
This parameter defines the direct influence of internally generated speed profile on speed reference for the drive. Higher value will make the axis more reactive. Too high value will cause oscillations of the axis.
Setting of this value is optional. The default value is 0. Find an optimal setting of i_stPosPara.rKpPos before increasing i_stPosPara.rKpFeedFwd.
Changes of the parameter value are taken into account immediately.
Excessive value of proportional gain of position controller and feed forward gain of the position controller may lead to oscillations of controlled axis.
|
|
|
UNINTENDED EQUIPMENT OPERATION |
|
Always start with low values of position controller gains and increase them gradually. |
|
Failure to follow these instructions can result in death, serious injury, or equipment damage. |
This parameter defines the position of optional software limit switch in positive direction. The software limit switch function stops movement of the axis when actual position of the axis is higher than position of the software limit switch.
NOTE: This function is active in Positioning and Jog modes. It is not active in Homing mode.
The software limit switch function is active when homing has been done (q_wStat.9 is TRUE) and i_stPosPara.diLsPosFwdSw does not equal 0.
Software limit switch function is not active in Modulo mode.
This parameter defines the position of optional software limit switch in negative direction. The software limit switch function stops movement of the axis when actual position of the axis is lower than position of the software limit switch.
NOTE: This function is active in Positioning and Jog modes. It is not active in Homing mode.
The software limit switch function is active when homing has been done (q_wStat.9 is TRUE) and i_stPosPara.diLsPosRevSw does not equal 0.
Software limit switch function is not active in Modulo mode.
