The value of I.S. relays for thesimplification and enhancement of control and indication loops has not been fullyappreciated hitherto, possibly because ofthe limited range of models which have been available to the system designer. The series comprises of models for interfacing from safe to hazardous area and forhazardous to safe area, and furtherincludes types which may be located in the hazardous area for interconnection between two or three I.S. circuits. Options of different voltages and variations of single- and double-pole contacts are included in the range.All units are constructed on RS chassis foruniversal DIN rail mounting, and include simple apparatus status for all intrinsically safe terminals. I.S. Relays Series RLSHI.S. Relays Series RLHS I.S. Relays Series RLHH >

The series RLSH relays are intrinsicallysafe interfaces which present voltfree contacts to the hazardous area in response to energisation of the safe area coils. The two sets of contacts on RLSH2A and RLSH2C are mutually isolated and may be connected into different IS field circuits, without the need to consider the combined safety of the two field loops. The most common applications include control and reset signals to field IS counters, signals to IS alarm/annunciator panels, calibration offsets on hazardous area load cells, second stage tone command on sounders, etc. > Supply Voltage, Vs nom....

The series RLHS relays are intrinsicallysafe interfaces which present voltfree contacts to the safe area in response to energisation of hazardous area coils. The certified parameters of the hazardous area coil terminals are such that they may be used in any IS field loop without further certification. The most common applications include digital input signals to the safe area arising from IS outputs given by self- powered field apparatus, or from an IS output delivered by a remote safe area into the intervening hazardous area. > Coil Voltage, Vs nom. 12 Volts Voltage Range 8 - 25 Volts Dropout...

WIStec 101 "The basics of Intrinsic Safety" This note is written to give the reader a broad understanding of the principles and practice of intrinsic safety without getting too involved in details.WIStec 102 "The earthing of Zener Barrier installations" Earthing is a requirement when installing zener barriers, and it often is perceived as being difficult to provide. In fact, theopposite is usually the case, and this note explains how satisfactory earthing is easily carried out.WIStec 103 "Zener Barriers or Isolation Interfaces?" Both isolators and traditional zener barriers have their particular...