Method and device for intrinsically safe redundant current supply of field devices

1. A method for intrinsically safe redundant current supply of a field device including a common current-limiting resistor in a mesh of the field device, the method comprising:

providing a current supply device including at least two current supply units, each current supply unit including a power-limiting unit comprising a controllable voltage source;

connecting the field device via a connection line to one or more field-device connection terminals of the current supply device;

measuring a voltage across the one or more field-device connection terminals, to obtain a measured voltage;

comparing the measured voltage with a reference value; and

reducing an output voltage, an output current, or the output voltage and output current of each current supply unit as a function of the measured voltage if the measured voltage falls below the reference value.

2. The method of claim 1 , wherein the output current of each current supply unit is reduced as a function of the measured voltage to a test current which is lower than a supply current of the field device.

3. A device for intrinsically safe redundant current supply of a field device, the device comprising:

a current supply device including at least two current supply units, each current supply unit including a power-limiting unit comprising a controllable voltage source;

a common current-limiting resistor in a mesh of the field device; and

a connection line,

wherein the field device is connected via the connection line to field-device connection terminals of the current supply device, and

wherein each power-limiting unit is configured to be adjusted using a measuring amplifier as a function of a difference between a measured voltage across the field-device connection terminals and a reference voltage.

4. The device of claim 3 , wherein the power-limiting unit further comprises a current controller/active current limiter.