Access and Modify ParametersΒΆ
Note
All modifications will be effective immediately. There is no extra plausibility check and values are not checked for limitations.
Use this functionality with care.
Some parameters are collected inside a structure in AXIS_REF, and can be accessed and modified immediately. They are the same parameters as used with function blocks MC_WriteParameter and MC_ReadParameter PLCopen.
The differences are:
- Only available with CMC_MOTION_KERNEL_REAL
- The parameter values are LREAL instead of DINT and can be used with decimals.
- The parameters will be effective immediately.
- There is no check for consistency or limits.
- The parameters for position control can be checked and modified by accessing the structure AXIS.parameter.position_control in addition.
| Parameter for position control | Description |
|---|---|
| KP | Proportional gain in positive direction. Used directly to multiply the following error and create the REFERENCE_PROP. |
| KF | Feed forward in positive direction. Used directly to multiply the speed reference and create the REFERENCE_FF. |
| KP_BACK | Proportional gain in negative direction. Used directly to multiply the following error and create the REFERENCE_PROP. |
| KF_BACK | Feed forward in negative direction. Used directly to multiply the speed reference and create the REFERENCE_FF. |
| TI | Integration time. When parameter is used the position control loop has an additional integral part. In TI cycle, the REFERENCE_ITG will reach the value of REFERENCE_PROP, when KI=100*KP. |
| KI | Proportional gain, used for integral part of position control loop. |
| KF_100 | Value for feed forward gain, if 100% would be used. |
| MAX_TIME | Delay time used for supervision of velocity. With MAX_TIME=0, no supervision is executed. |
| D_XS_MAX | Maximum possible velocity in [u/cycle]. The maximum allowed following error is part of the parameter structure, PLCopen parameter paraMaxPositionLag. |
| REF_MAX | Limit for SPEED_REFERENCE. |
Element actual of AXIS_REF
The element actual represents actual values from inside the position control loop.
| Value | Description |
|---|---|
| POSITION | Actual position in [u] to control the axis. |
| CONTROL_POSITION | Reference position in [u] which is actually used for control loop. |
| D_XS | Distance in [u] to be moved per cycle. |
| D_XSS | Following error in [u]. |
| REFERENCE_PROP | Proportional part for SPEED_REFERENCE. |
| REFERENCE_FF | Feed forward part for SPEED_REFERENCE. |
| REFERENCE_ITG | Integral part for SPEED_REFERENCE. |
Possible to use different gain for forward/backward movement , possible improvement for hydraulic axis or vertical movement
See parameter KP/KP_BACK and KF/KF_BACK.
Limitation for Velocity and Acceleration and Deceleration
From library version 3.1 on, these values are not limited to the 16-bit value range (32767). The limit for velocity is calculated by the values given at CMC_AXIS_CONTROL_PARAMETER_REAL and the acceleration is limited such that this velocity can not be reached faster then 1 cycle.