Operating Instructions for Helical Flow Meters Type SRZ
KEM
7
3.2 Electrical
Make sure that the flow meter is grounded.
Note
The housing of the SRZ* is connected to the shield of the cable. In bigger systems a separate
grounding of the meter might be required for avoiding high currents in the cable shield. In that case
the shield might be left open or grounded via a capacitance of e. g. 100nF to avoid ground loops.
Note
Inproper grounding and shielding may lead to bad EMC behaviour or danger to your health!
Connect the SRZ* via a shielded cable to the control unit. The SRZ is specified for a supply voltage of
15 V or 24 V and will operate at supply voltages from 12 V up to 30 V,
Note
Make sure that all cable and wires are connected and fixed properly before applying power to the
SRZ*!
Figure 1: Output stage of the VTE*
The output driver for the frequency output is an asymmetrical push pull output stage with the
protective resistors of R1 = 720
Ω
and R2 = 470
Ω
as shown in Note
.
Note
The output can withstand a short circuit to ground for an infinite period whereas a short circuit to
the positive supply for longer than a few seconds might destroy the output stage!
3.3 Ex
installation
The SRZ*-Ex is intrinsically save when operated with an EWS or zener barriers as described in the
technical data (see chapter 6.3)
Mount the SRZ* as described in chapter 3.1.
Connect the SRZ to the intrinsically safe power supply type EWS or to suitable the zener barriers.
Note
When used in hazardous areas the SRZ* must not be connected to any circuitry except our
intrinsically safe power supply type EWS or suitable zener barriers.
