HEC-HMI Harsh Environment HMI is available as HMI only or with a PLC in the same enclosure. With extended operating temperature range of -40 to 80 °C and 8–32 Vdc input power, the backlit LCD is available in 2 line x 16 or 4 line x 20 character configurations, with nine pushbutton inputs and four programmable indicators. Network communication is via CAN port or a field-configurable serial communication port for RS-(232) 422/485.