HMI (Human Machine Interface) Text display OP370-B The 20 keys can be defined to be function keys (In which 12 keys can be defined to be number keys and other usage), take the place of some mechanic keys on the control tanks Choose communication format freely, RS232/RS422STN LCD display with back light, can display 24 letters*4 lines3.7 inch, monochrome LCD, 192*64 pixels, 1 MB FlashROM, 20 function keys.