Knick loop-powered isolators for 0 ... 20 mA signal transmission. These modules are available as hazardous-area input and hazardous-area output isolators. Due to their patented design (German patent 3526997), they are considered to be the most reliable solution for isolating standard signals without an external power supply. The IsoTrans 36 and 37 isolators are not only suitable as highly reliable isolators for normal applications, they also meet the most stringent requirements that can be set for potential isolation. There is no need for power supply wiring.

The WG 21 repeater power supply is used to supply intrinsically safe 2-wire transmitters. It supplies the transmitter with power and transmits the measurement signal to the output galvanically isolated and with high accuracy. In addition to the analog signal, the WG 21 also optionally transmits data protocols for SMART transmitters (HART). It allows for bidirectional communication between the field device from every point of the wiring.

The high supply voltage, the good hazardous-area ratings and the broad-range power supply allow for universal use. Cables up to 1400 m in length can be used without any problems. Thanks to a new transformer-based transmission technique, the WG 21 achieves an extraordinarily high transmission accuracy for hazardous-area applications. The encapsulation provides maximum operating safety, long-term stability, and disruptive strength even under extreme ambient conditions.

Facts
• SMART transmission (optional): bi-directional point-to-point transmission of digital data
  according to the HART® specification
• High supply voltage and good hazardous area specifications: universal use
• Broad-range power supply: just 2 versions for all mains voltages
• Protective separation according to EN 61140
• Protection of maintenance staff and subsequent devices against excessively high voltages
• 3-port isolation: protection against incorrect measurements or damage to the equipment
  due to parasitic voltages
• High transmission accuracy: exact transmission of measured values
• Explosion protection according to ATEX trouble-free use in hazardous areas
• Modular housing 22.5 mm: straightforward installation due to compact design
• 5 year warranty

The passive WG 25 repeater power supply is loop-powered. It is used for galvanic hazardous-area separation of a 2-wire supply line and transmits both 4 ... 20 mA and HART® signals in both directions. With a voltage drop of just 4.2 V, the WG 25 uses the supply optimally so that all common 2-wire transmitters can be connected.

Compared with active repeater power supplies, it has considerable price and reliability advantages. Multi-channel systems require only one central, safe-area power supply that does not even need protective separation.

Facts
• Low-cost due to omission of the integrated power supply
• No mains power required costs savings doe to lower wiring effort
• No mains interference
• Low power loss no unnecessary heating in the enclosure
• Protective separation according to EN 61140: protection of the maintenance staff
  and subsequent devices against excessively high voltages
• HART® transmission: bi-directional point-to-point transmission of digital data
  according to the HART® specification
• EMC tested RFI suppressed and surge proof: reliable operation even
  with electromagnetic interference
• Maximum reliability: no maintenance work so the associated costs are not incurred
• 5 year warranty