gefran HMF P, Instruction Manual

Page: 28 / 35

28
80636B_MAN_HMF - HWF_05-2022_ENG
Application for use relevant to the designated category
The HMF, HMF P/S, HWF and HWF P/S series transducer can be used in a pressure sensing chain in order to
stop any pressure generating system if a pressure threshold is overcome.
The threshold is only set in factory and can’t be changed by the user.
In diagram “A” (Fig. 10.2) is shown a possible application: the sensor detects the pressure and gives in output an
analog electrical value proportional to the pressure itself; SRP/CS compares the signal with its internal alarm threshold:
if the threshold is exceeded the SRP/CS will stop the pressure generation systems.
Fig� 10�2� Application diagram A - Current 2-wires output
10�1� NE21 and NE43 compatibility specifications
The HMF, HMF P/S, HWF and HWF P/S series are fully compatible with the NE21 and NE43 Namur recommendations
(refer to Tab. 10.4).
Failure HMF, HMF P/S, HWF, HWF P/S
Broken power cable Electrical output ≤ 3.6 mA
Sensor not connected Electrical output ≤ 3.6 mA
Broken power supply Electrical output ≤ 3.6 mA
Broken chip Electrical output ≥ 21 mA
Pin detachment Electrical output ≥ 21 mA
Pressure over 200% of the span vs factory zero @ RT Electrical output ≥ 21 mA
Preload loss exceeds -30 % of span vs factory zero @ RT Electrical output ≥ 21 mA
Error on primary or first amplification stage Electrical output ≥ 21 mA
Overvoltage Electrical output ≤ 3.6 mA (*)
Undervoltage Electrical output ≤ 3.6 mA (*)
Error in the program sequence Electrical output ≤ 3.6 mA (*)
Overheating of the electronics Electrical output ≤ 3.6 mA (*)
Error RAM Electrical output ≤ 3.6 mA
Error ROM Electrical output ≤ 3.6 mA
Error CPU Electrical output ≤ 3.6 mA
Analog output error Electrical output ≤ 3.6 mA
Tab� 10�4� NAMUR NE21 and NE43: Analog output value.
(*) In such conditions the Alarm Type can be programmed via HART at ≥ 21 mA.