A side project to log industrial robots via their PLC (24V) interface.
The PCB consists of:
- ST32F407VGT (Cortex M4) as the MCU.
- SD card for storing detailed logs.
- DP83848 ethernet PHY hooked up to the M4 RMII interface, connecting it to the LAN, so logs can be downloaded, statistics viewed, live view, settings and more.
Using netbios names and DHCP by default, so easily accessible without pre-setting.
- Optocouplers to completely seperate the PLC signals from the board.
- Battery backup for SRAM and RTC, even poweroff’s are logged.
- Status leds for Power On, SD card OK, Ethernet OK, MCU running (flashing).
- Firmware upgradable from LAN/Internet or microSD.
The PCB was designed to fit a compact DIN rail case and using screw terminals for power and PLC signals.
For once it was a really smooth experince, only screwed up the battery polarity, which was easily fixed by using another holder.