E+H Nivotester FTW325-C1A1A Conductive Point level switch

Point level switch with intrinsically safe signal circuit for connecting to conductive sensors Application

• Two-point control also for hazardous areas

• Overfill protection for tanks

• Dry running protection for pumps

• Point level detection Your benefits

• Cable monitoring up to sensor

• Adjustable sensitivity range

• ATEX, FM and CSA approval

• Measuring range up to 200 k

• Alarm relay can also be used as a second point level relay (SPDT)

• Compact housing for easy series mounting on standard DIN rail in the cabinet

• Pluggable terminal blocks make wiring easy

• Connection to different supply voltages

Function The Nivotester supplies a small amount of alternating current to the measuring point via the signal line. The cable is connected to the ground probe or the metal vessel and the probe. The voltage drops if an electrically conductive medium touches the probe. An amplifier circuit in the Nivotester causes the relays to switch.

Signal transmission The intrinsically safe signal input of the Nivotester FTW325 is galvanically isolated from the power supply and from the output. The Nivotester supplies the conductive probe with alternating current via a two- or three-wire cable and monitors the voltage of this cable. If the medium reaches the switch point of the probe, the voltage between the probe and the Nivotester is reduced. The switching of the output relays at the Nivotester depends on which fail-safe mode has been configured.

The switching state of the relays is indicated on the front panel of the Nivotester by means of two yellow LEDs. Fail-safe mode The choice of fail-safe mode affects how the relay works in quiescent current fail-safe mode. • MAX = Maximum fail-safe mode: the relay de-energizes when the level rises above the switch point (probe covered), a fault occurs or the power fails. Used for overfill protection, for example. • MIN = Minimum fail-safe mode: the relay de-energizes when the level falls below the switch point (probe uncovered), a fault occurs or the power fails. For use with dry running protection or pump protection, for instance.