- In some environments with relatively large interference, the digital input is also susceptible to interference, especially the photoelectric switch (including the photoelectric proximity switch), which will bring a lot of pulse signals of several milliseconds to tens of milliseconds at the HJ3200 digital input point, affecting the data. collection.
- The HJ3200 digital filter parameters are used to deal with these interference signals. If the digital input filter coefficient is set to 50, then the pulse width of the input signal is less than 50 milliseconds, the HJ3200 will ignore this signal, and the PLC will not receive this signal. Interfering signals, but normal signals can reach the PLC through the digital input filter.
- As shown in the figure above, the first three interfering signals will be discarded by the HJ3200 module because their pulse width is less than the set value of 50 milliseconds. The following normal signals start from 200 milliseconds to 250 milliseconds, and the HJ3200 module will not discard the signals. After sending it to the PLC, after 250 ms, the PLC can receive the input signal. The delay of 50 ms is brought about by the HJ3200 filtering.
- Set the digital input filter of HJ3200 device as follows:
- Digital input filtering is a newly added function. It needs to configure the software version “PROFINET-IO-Configuration Software V-1.4.2-1” and the software version of the device “HJ3200-PROFI-V3.2.N”
The software version of the device can be read by the following method.
If the software version of the device is lower than HJ3200-PROFI-V3.2.N, it is recommended to upgrade the device software.