Electrical and/or electronic supply circuit and method for providing a supply voltage

Abstract

An electrical and/or electronic supply circuit, which serves to provide a first or a second, essentially constant value of a supply voltage, which supply voltage serves to operate an operating electronics. The supply circuit serves to output the first value of the supply voltage when the supply voltage is derived from a first voltage source, and the supply circuit serves to output the second value of the supply voltage when the supply voltage is derived from a second voltage source.

Claims

1. An arrangement comprising: an electrical and/or electronic supply circuit that provides a supply voltage, which serves to output a first value of the supply voltage when the supply voltage is derived from a first voltage source and a second value of the supply voltage when the supply voltage is derived from a second voltage source, wherein said second voltage source is a chargeable energy storer and an operating electronics for a radio unit for a plant of process automation technology which serves for the functions of the radio unit and provides a voltage for the supply of a field device which is connectable to said radio unit; and a detection circuit in said operating electronics which measures the values of the supply voltage and sets said operating electronics to different operating modes based on the measured value; wherein, in the case in which the supply voltage is delivered from the second voltage source a radio connection via the radio unit is uninterrupted for a predetermined period of time and wherein said field device connected to the radio unit is switched off to save energy.

2. The arrangement as claimed in claim 1, wherein: the operating electronics has a first and a second mode; and said operating electronics sets said first or second operating mode as a function of the first or the second value of the supply voltage.

3. The arrangement as claimed in claim 1, wherein: the supply circuit serves to output a third value of the supply voltage, which differs from the first value and the second value of the supply voltage, when said energy storer is being charged via said first voltage source.

4. A radio unit for a plant of process automation technology comprising an arrangement as claimed in claim 1, wherein: the supply circuit Includes a power supply and an energy storer, and the supply circuit outputs the first value or second value of the supply voltage as a function of whether the voltage supply occurs via the power supply or the energy storer, wherein the radio unit includes said operating electronics, which measures the values of the supply voltage and sets said operating electronics to different operating modes based on the measured value, wherein: in the case in which the supply voltage is delivered from the energy storer a radio connection via the radio unit is uninterrupted for a predetermined period of time; and said field device connected to the radio unit is switched off.

5. The radio unit as claimed in claim 4, wherein: said operating electronics serves to set a first or second operating mode of said operating electronics as a function of the value of the supply voltage.

6. The radio unit as claimed in claim 4 wherein: said operating electronics has a communication interface and in the case, in which the supply voltage changes, from the first value to the second value, said communication interface serves to transmit a corresponding radio signal.

7. The arrangement as claimed in claim 1, wherein said first voltage source is an alternating voltage source.

8. The arrangement as claimed in claim 1, wherein said first voltage source is a grid connection.

9. The arrangement as claimed in claim 1, wherein said second voltage source is an chargeable energy storer.

10. The arrangement as claimed in claim 1, wherein said first value of the supply voltage differs from said second value of the supply voltage.

11. A method for providing a supply voltage, by means of which supply voltage an operating electronics of a radio unit for a plant of process automation technology is operated, said radio unit provides a voltage for the supply of a field device which is connected to the radio unit, comprising the steps of: a first value of a supply voltage is output when the supply voltage is derived from a first voltage source; a second value of a supply voltage is output when the supply voltage is derived from a second voltage source; and measuring the values of the supply voltage and sets said operating electronics to different operating modes based on the measured value, wherein: in the case in which the supply voltage is delivered from the second voltage source a radio connection via said radio unit is uninterrupted for a predetermined period of time; and said field device connected to the radio unit is switched off.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention will now be explained in greater detail based on the appended drawing, the sole figure of which shows as follows:

(2) FIG. 1 is a schematic representation of the construction of a supply circuit according to a form of embodiment of the proposed invention.

DETAILED DISCUSSION IN CONJUNCTION WITH THE DRAWING

(3) The supply circuit SC is connectable to a voltage source, not shown, via input terminals IT. Supply circuit SC is preferably integrated, in such case, in a radio unit RU, which is connectable to at least one field device. However, the supply circuit can also be integrated in other electrical and/or electronic devices, such as, for example, a field device, i.e. a sensor, actuator or other process-near component. The voltage source can be, for example, an alternating voltage source. The voltage source is, for example, a grid connection at 230V and 50 Hz. Furthermore a rectifier RE can be connected, for example, to the input terminals IT, in order to convert an, in given cases, applied, alternating voltage into a direct voltage.

(4) Furthermore, supply circuit SC includes two outputs 01, 02, via which a first and a second supply voltage can be tapped. The first supply voltage serves, in such case, for operating the operating electronics OC and the second supply voltage serves for operating a separate field device connectable to the radio unit or for operating a bus system such as, for example, a HART bus system. Field devices and/or fieldbus systems are connectable, in such case, for example, via connection clamps to the radio unit and supply circuit SC.

(5) It is, however, also possible to supply a field device, which is connectable to the radio unit, with electrical energy via the operating electronics, thus by means of the first supply voltage. For this purpose the operating electronics can have other outputs, not shown, to which a field device can be connected and supplied with electrical energy

(6) Via second output O2, for example, a second supply voltage of 24 V can be output, while, via the first output, a first or a second or a third value of the first supply voltage of, for example, 10 V, 11 V or 12 V can be output for operating electronics OC. The first supply voltage can thus assume different values. As a function of these different values, the operating electronics OC of the radio unit RU, for example, switches into different operating modes or sets off one or a number of radio signals.

(7) A corresponding control unit CU can serve for charging the energy storer ES. Additionally, for signaling the different states, such as, for example, energy storer ES is charging, energy storer ES is discharging or energy storer ES is full etc., a signaling system LED such as, for example, a light emitting diode, can be used; signaling system LED is, for example, likewise connected to control unit CU.

(8) In error free operation, the switch S is in the position 1, so that the first supply voltage of, for example, 12 V output by the transformer TR is directly fed to the first output O1. In the case of an interruption of the supplying by the voltage source via the terminals IT, the energy storer ES discharges and provides a voltage of, for example, 10 V. Since, for example, only limited power is available in a hazardous area, a rapid (re-)charging of energy storer ES and simultaneously supplying, in given cases, a field device connected to the radio unit is not possible. Thus, if the energy storer ES is charging, switch S switches to position 2. Then, the energy storer ES is charged and, however, for example, only 11 V is provided via first output O1. To this end, a voltage converter VC can be provided.

(9) The supply circuit SC, according to the example of an embodiment in FIG. 1, furthermore includes a galvanic isolation GI between input, primary current circuit C1 and output, secondary current circuit C2. For this purpose, supply circuit SC includes a transformer TR and an opto-coupler OPT.

(10) Energy storer ES of the supply circuit can be designed so that at least the radio network, i.e. the radio connection via the radio unit, is uninterrupted for a predetermined period of time, for example, about 30 minutes in the case of an interruption of the grid voltage. In this period of time, maintenance information or emergency signals can be transmitted.

(11) Additionally, in the case in which the supply voltage is delivered from the energy storer, the field device connected to the radio unit must, in given cases, be switched off, in order to save energy. For this purpose, the supply circuit can thus output corresponding information in the form of the provided value of the supply voltage.

(12) In such case, for example, the states supply is in order (according to specification), supply is in order and energy storer is being charged and supply is interrupted, energy storer being substituted can be signaled by means of different values of the supply voltage, for example, 10 V, 11 V, and 12 V, respectively. These values of the supply voltage can be measured, for example, by means of a detection circuit in the operating electronics. Based on the value of the supply voltage determined in such a manner, different operating modes of the operating electronics can then be set. For example, a connected field device can, in given cases, be switched off, or a warning or an all clear can be sent via the communication interface of the radio unit.