HART E018-P, User Manual, Page: 46 / 64

User Manual E018-P
Page 46 FW_E018-P_M_v0301-01_EN
Pulse-signal PNP / PNP-LP
The unit is suitable for use with flowmeters which have a PNP output signal:
● 3.0 V is offered on terminal S3 which must be switched by the sensor to terminal S2 (SIGNAL).
● For reliable pulse detection, the signal must always be above 1.4 V or below 1.0 V.
● For less power consumption, use a sensor which is normally open and briefly closed.
● For better noise immunity and if no high sensor input frequencies are expected, select signal
setting PNP-LP (low-pass signal noise filter) which limits the maximum input frequency to avoid
pulse bounce (see
SETUP 5.1: FLOWMETER > SIGNAL [»25]
).
Power supply type PD provides a sensor supply voltage of 8.2, 12, or 24 VDC.
S1
S2
S3
P3
↓
+
J1-J2
8.2 ; 12V; 24V V
Common system ground
PNP-LP*
R
3V
↓
+
┴
MEM
Fig. 34:
Terminals S1-S3 and P3: Pulse signal input PNP
Reed switch
The unit can be used with flowmeters which have a reed switch. To avoid pulse bounce from the
reed switch, it is advised to select REED LP – low-pass noise filter, which limits the maximum input
frequency (see
SETUP 5.1: FLOWMETER > SIGNAL [»25]
). Make sure the contact resistance of the reed
switch is less than 1V@2uA=500 kOhm.
S2
Common system ground
S3
REED-LP*
┴
R
3V
S1
MEM
Fig. 35:
Terminals S1-S2: Reed switch input