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IECEx Intrinsically Safe Barriers

Intrinsically Safe Barriers and Repeater Power Supplies from Aplisens provide the necessary energy limiting connection to instruments located in a hazardous area to satisfy requirements of an Intrinsically Safe installation. They ensure dangerous power levels do not reach instruments or ignite a potentially explosive environment.

Through galvanic isolation, these barriers provide the highest degree of protection without compromising the integrity of your measurement. In addition, these devices can enhance immunity to interference.

ZS-30/1Ex
Intrinsically Safe Barrier / Repeater Power Supply / Signal Converter

The ZS-30/1Ex power supply and isolator is designed to supply power to transmitters with a 4...20 mA signal in a two-wire transmission and either repeat or convert that signal through galvanic separation into one of the standard signals used in automatic control: 4…20mA, 0…20mA; 0…5mA; 0…10V, 0…5V, 1…5V, 2…10V.

Input, Output and Supply circuits are galvanic separated from one another for maximum protection, resistance to interference and performance.

              • IECEx Ex ia approval
                [Ex ia Ma] I
                [Ex ia Ga] IIC
                [Ex ia Da] IIIC
              • Galvanic isolation
              • Universal input power: 20…253 V AC/DC
              • Nominal output voltages from 7.5 to 24 VDC
              • Digital calibration of measurement chain

              Data SheetIECEx certificate

Used as a conventional repeater power supply, the ZS-30/1Ex will safely power and transmit the 4-20 mA signal from a field instrument back to the control system or PLC. Nominal supply voltages include:

  • 24 VDC
  • 22 VDC
  • 18 VDC
  • 15 VDC
  • 7.5 VDC

The ZS-30/1Ex can also provide a signal conditioning function and provide a conversion to the one of the following outputs:

  • 4-20 mA (Standard, repeater function)
  • 0 to 20 mA
  • 0 to 5 mA
  • 0 to 5 VDC
  • 1 to 5 VDC
  • 0 to 10 VDC
  • 2 to 10 VDC

Construction

Electronic Design
The electronic structure of the ZS-30/1Ex power supply-separator consists of 3 circuits isolated from each other:

a) Power Circuit. The power supply circuit of the power supply - separator was based on a pulse converter, working on a specialized integrated driver with a built-in keying transistor, ferrite transformer and several auxiliary elements. The output winding of this converter is used to supply the output signal circuit, as well as to supply the second impulse converter, which is responsible for supplying the intrinsically safe circuit. The protection from the mains side includes a fuse and a varistor.

b) Input Circuit. The input circuit supplies voltage of one of six values from 7.5V to 24V, which supplies the transmitter installed in the hazardous area via a two-wire line. The 4…20mA signal generated in line by the converter, supplied with the above-mentioned voltage, is introduced to the analog-to-digital converter of the 16-bit microcontroller, and then, by means of 3 digital optocouplers, it is transferred to the output 16-bit digital-to analog converter. The input circuit is protected by a protection system limiting the short-circuit current and input voltage to the hazardous zone. This circuit is part of the input circuit and consists of a series current limiter consisting of a non-destructible resistor and 3 Zener diodes connected in parallel, which are designed to limit the voltage.

Nominal voltages can be 7.5; 15V; 18V; 20V; 22V and 24V. Limiting diodes are protected by a 32mA, 250V fuse according to IEC 60127.

c) Output Circuit. The output circuit converts the analog signal from the input circuit to one of the standard analog output signals. The basic element of the output circuit is a 16-bit digital-to-analog converter, equipped with a voltage output and a current output, as well as digital optocouplers. The output circuits of the digital optocouplers are protected by Zener diodes and a 32mA, 250V fuse connected in series according to IEC 60127. The power supply unit, from the output circuit side, can cooperate with devices powered by mains transformers from the 230V 50Hz mains. The output circuit is protected by a Transil diode and a 32mA, 250V fuse connected in series according to IEC 60127.

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