AC/DC-sensitive Differential Current Sensors (DI-Sensors) Closed loop sensors with magnetic probe for highest accuracy and reliability Differential current range typically 30 to 300 mA Full load current to 50 A Single +5 V voltage supply Voltage output for direct connection at A/D converters Automatic demagnetization of the sensor core for offset decrease Self-monitoring and test functions Measuring accuracy 1.5% Smallest temperature drift, highest long-term stability Metal screen against external fields Frequency range DC to 10 kHz Variants with passing through opening and with integrated primary conductors, with or without test winding Active sensors with integrated electronics Economical construction Applications Control devices with AC/DC-sensitive differential current sensors are used primarily in transformerless solar inverters. An important safety function of these devices is the monitoring of the leakage current of the entire system from photovoltaic - modules and inverter against earth. A defective system can become dangerous for people or release fires. Before it comes so far, the inverter must disconnect from the grid. The leakage current contains DC and AC components. Therefore an AC/DC-sensitive monitoring unit is necessary. Their heart is the VAC differential current sensor, whose output voltage is evaluated by the control system of the solar inverter. Generally protection devices with AC/DC-sensitive differential current sensors can be used everywhere, where flat or pulsating DC can develop, whose amount is permanently greater than zero. Further examples are power supplies producing high DC voltages or uninterruptable power supplies. Variants of the VAC Sensors It is both a type available with an opening for the primary conductor, as well as types with built-in primary conductors for PCB mounting. There are versions with two or four conductors for single and three phase systems. The additional functions demagnetization, error signaling and internal test power are accessible through defined levels at the inputs / outputs Vout and Vref. Allstromsensitive Differenzstromsensoren (DI-Sensoren) Seite 1 von 7 Functional description, technical data, available Types Item no. T60404-N4646- X950 X960 X975 X976 Style Dimensional diagram no. 1 2 3 4 Primary conductor style opening via PCB. Two via PCB. Two via PCB. Four conductors conductors conductors A= 6,2 mm for A= 6,2 mm for A= 4,9 mm for operating current operating current, operating current, one conductor for one conductor for external test current external test current Properties Supply voltage 5 V Supply current typ. 17 mA Maximum primary current 50 A Nominal differential current 300 mA Output voltage reference voltage (0,74 x differential current / 300 mA) Measuring range 850 mA Output voltage range 0,5 V 4,5 V Reference voltage 2,5 V reference voltage, internally generated or Vref=1.4 to 3.5 from external source Frequency range 0 10 kHz, limited by internal low pass filter. An additional external filter with e.g. 5 kHz roll off frequency is recommended. Measuring error < 1,5 % of nominal differential current at T = 25C amb Temperature drift < 0,1 mV/C -40 +85C Response time (up to 90% of nominal differential < 35 s current) Isolation strength to be maintained by acc. to EN50178 (primary- and a proper insulation of test current conductor vs. signal the primary onductor and supply voltage connections) - system voltage 600 V - working voltage 1.000 V Additional functions Error condition - indicated by - output voltage < 0,5 V - critieria - break or short circuit of the magnetic probe, supply voltage smaller 4 Volts, during the demagnetization cycle. Demagnetization of the Sensor core - triggered by - feeding the supply voltage or transition from <1 V to 2,5 V (normal voltage) at the reference voltage input, i.e. after test current cycle - duration of cycle - 120 ms Internal DC test current for self test - triggered by - setting reference voltage to 0 V (<1 V) - output signal at test current - U DC = +0,25 V at Vref = 0 V. A possibly appearing primary current is superimposed Allstromsensitive Differenzstromsensoren (DI-Sensoren) Page 2 of 7