Supply Isolation Amplifier

HART-Supply Isolation Amplifier

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The HART supply isolation amplifier AD-STH 40 GVC is designed for the galvanic isolation and amplification of transmitter signals (0/4-20 mA) and standard analog signals (0/4-20 mA and 0/2-10VDC). When connecting a 2 - wire transmitter, it is powered directly through an electrically isolated and current limited power supply voltage. Because the AD-STH 40 GVC is permeable on the current path for FSK signals (Frequency Shift Keying, eg HART-protocol) also a smart HART-transmitter can be connected at the input of the supply isolation amplifier. This HART transmitter can be programmed or read out from the output of the AD-STH 40 GVC using the integrated programming resistor. The standard signals 0/4-20 mA and 0/2-10 V are freely selectable via switch or terminal on both the input and at the output. All ranges are calibrated fixed, but can be adjusted via front-trimmer. In addition, this device comes standard with a configuration interface AD-PC, with which the input and output measurement signal with the optional AD-Studio programming software in the range of max. 20 mA or 10 VDC can be freely programmed. The selected linear output signal follows the input size up to a limit independent of the connected load. Input, output and power supply voltage are galvanically isolated from each other with high insulation. An integral electronic wide range power supply with high efficiency prevents strong heating and allows high output loads.


Galvanically isolated supply of a smart HART-transmitter while separation, amplification or conversion of standard analog signals.


  Specific characteristics

  • All standard signals at the input and output are freely selectable
  • FSK transmission (e.g. HART protocol)
  • Switchable zero and span trimmer
  • Special signals can be parameterized via interface
  •   Business data

    catalog number AD-STH 40 GVC



      Technical specifications

    Input current
    Measuring range 0 ... 20 mA; 4 ... 20 mA 1)
    Input resistance ca. 75 Ohm
    Resolution 10 Bit
    Input voltage
    Measuring range 0 ... 10 V; 2 ... 10 V 1)
    Input resistance >700 kOhm
    Resolution 10 Bit
    Transmitter supply
    Open-circuit voltage ca. 24 V DC
    Full load voltage ca. 20 V DC
    Current limit ca. 30 mA
    Input filter
    Setting range (via interface) 10 ms / filter value (0 ... 30000)
    Output current
    Output range 0 ... 20 mA; 4 ... 20 mA 1)
    Max. burden 400 Ohm
    Residual ripple 50 ľAss
    Resolution 11 Bit
    Output voltage
    Output range 0 ... 10 V; 2 ... 10 V 1)
    Min. burden 10 kOhm
    Residual ripple 20 mVss
    Resolution 11 Bit
    Voltage range AC 50 ... 253 V AC, 50/60 Hz
    Nominal voltage AC 230 V AC
    Voltage range DC 20 ... 253 V DC
    Nominal voltage DC 24 V DC
    Power consumption AC / DC 3,9 VA / 1,9 W
    Trim range ca. +/- 20 %
    Transmission behaviour
    Basic accuracy < 0,3 %
    Temperature influence 100 ppm/K
    Response time ~ 70 ms
    Dimensions (WxHxD) 18x110x134 mm
    Type of protection IP 20
    Connection method detachable terminal clamp
    Terminals, wire cross section 2,5 mm˛ flex wire / 4 mm˛ one wire
    Bolting torque terminals 0,5 Nm
    Weight ~ 130 g
    Manner of fastening 35 mm DIN rail 35mm
    Environmental conditions
    Ambient temperature 0 ... 50 °C
    Storage and transport -10 ... 70 °C (no thawing)
    Product family standard EN 61326 2)
    Emitted interference EN 55011, CISPR11 Cl. B
    Electrical safety requirements
    Product family standard EN 61010-1
    Overvoltage category II
    Pollution degree 2
    Galvanic isolation, test voltages
    Input / output 2,5 kV (1 min.)
    Signal / supply unit 4 kV (1 min.)
    Protection circuits
    Input electrical surge protection
    Output electrical surge protection
    Power supply Protection against overvoltage, overcurrent and reverse polarity
    1) Special signals are configurable via the interface.
    2) During electromagnetic disturbance minor changes in output signal are possible.

      Block and wiring diagram