Question:
If the DrivePLC is applied in order to realize a switch-off positioning, e. g. in connection with an 8200 frequency inverter, the switching from high to low speed can cause a jerk when linear ramps are applied. This has no effect on the achievable positioning accuracy, but it can be negatively noticeable and stress the mechanics extremely. Can an S-ramp function be applied in case of switch-off positioning with 8200 vector, DrivePLC and coupling of both components via systembus?
Answer:
Yes.
One possibility is activation of code C0182/000 (S-ramp) in the frequency inverter 8200 vector. This ensures a smooth (almost jerk-free) switching from high to low speed.
Disadvantage: If the S-ramp function is not inactivated from low speed to standstill (stopping of the drive) by C0182/000, the PT1 behaviour of the S-ramp function causes an inaccurate switch-off positioning. A remedy is to switch off the S-ramp function shortly before standstill by writing code C0182/000 of the 8200 vector frequency inverter by function block L_ParWrite.
Alternatively an S-ramp function of function block L_SRFG (no PT1 behaviour, but defined phases with S-smoothening) is available in the library LenzeDrive.lib. This function block can be used on the DrivePLC for the 8200 vector's setpoint generation. In this case the ramp generator of the 8200 vector is to be inactivated (C0012/000 = 0.00 s, C0013/000 = 0.00 s).
