In general, when the nozzles are operated with pulse width modulation systems, they always enter in the next lower drift reduction class.
The next lower class for Lechler nozzles are 90%, 75%, 50% or 0% while the use regulations/pressure remain the same.
If the PWM system is not used (switched off or duty cycle set to 100%), the registration for nozzles without a PWM system apply.
Using the example of IDKT 120-06 POM and IDTA 120-05C, the drift classifications are as follows:
| Use regulation | Operation | Drift reduction class | ||
| IDKT 120-06 POM |  | 1 bar | Normal operation „no pulsing“ | 90% |
| PWM-Pulse mode | 75% | |||
| IDTA 120-05C |  | 1 – 1.5 bar | Normal operation „no pulsing“ | 95% |
| PWM-Pulse mode | 90% |
Lechler PRE, IDTA and IDK 90 nozzles operated with PWM under same use regulations switch from 95% to 90% drift reduction class.
Overview