User manual HONEYWELL FD

[. . . ] Pressure monitoring in safety technology Pressure limiters in safety technology may be used only together with a suitable switching amplifier, e. In Ex systems, the switching amplifiers must be installed outside the Ex zone ( 1). [. . . ] Pressure limiters in open-air installations Pressure limiters can be used in open-air installations, but it is necessary to protect the device by a protective cover against the direct climatic influences. Setting the shutoff pressure Remove the terminal box cover, loosen 4 M4 Allen screws for this purpose. Loosen the M3 set screw for spindie locking on the front of the switching device by approx. Set the wanted shutoff pressure with the setting spindle. The pointer on the scale serves as an approximate value, accurate adjustments must be made outside the installation with compressed air and a suitable pressure gauge. After setting tighten the locking screw again and fasten the terminal box lid (pay attention to the correct position of the sealing ring). Pressure limiters with mechanical interlock Instead of the microswitch with automatic reset, a , , bistabie" microswitch is built into the limiters. Lf the pressure reaches the value set on the scale, the microswitch switches over and remains in this position. the lock can be released by pressing in the unlocking button (identified on the scale side of the switching device by a red dot). The maximum pressure limiter cannot be unlocked until the pressure has fallen or at minimum pressure limiters the pressure has risen. The pressure limiters are precision devices which as a rule have to fulfil a safety function. they are carefully adjusted and tested in the factory. [. . . ] A switching amplifier type Ex 041 or a comparable device which correspond to the nominal conditions or DIN 19 234 and is designed additionally for wire breakage and short circuit monitoring is always required. Pressure limiters in safety technology must never be connected directely to line voltage. [. . . ]