The devices are designated to measure and monitor line-to-line and phase voltages, currents, active and reactive powers, true power factor, THD for both voltage and current one- and three phase LV, HV and VHV networks and sense the temperature inside a switchboard. Devices can be optionally assembled with communication line (RS232, RS485) and support communication over ethernet or with modem with external convertors. SML 33 / SMM 33 / SMN 33 instruments can be set to use the Modbus-RTU protocol where the address, baud rate and parity bit (even / odd / no parity) are specified. The instrument sends back a reply within 600 ms from receiving a command. A gap between bytes corresponding to maximum 1.5 characters (bytes) is allowed while receiving a command or transmitting a reply.

Characteristics

• true root-mean-square values of voltage and current (TRMS)
• active and reactive power, four quadrant presentation in compliance with IEC375
• both true power factor (PF) and power factor of fundamental harmonics (cos fi)
• Total Harmonic Distortion and harmonics of voltage and current up to the 20. order
• built-in temperature sensor
• single-phase, two-phase, three-phase or Aron connection
• direct & undirect voltage connection
• optional remote RS-485 communication link
• panel mounted (SML) or DIN-bar mounted (SMM) version