KROHNE UFM 500 EN - Manual (Page 6)

6
(Suggestions for installation continued):
1.2 Pipe flanges
Flange spacing
Refer to dimensional drawings (section 10.4 and 10.5),
in addition allow for thickness of gaskets.
Position of flanges
•
Install flowmeter in line with pipe axis.
•
Pipe flange faces must be parallel to each other, max.
permissible deviation: L
max
- L
min
≤
0.5 mm (0.02”).
1.3 Grounding
Warning
Instrument should be properly grounded to avoid
personnel shock hazard!
1.3.1 Standard grounding
The flowmeter must normally be grounded via the
protective conductor PE incorporated in the power
supply cable. Connect the protective conductor to the
separate U-clamp terminal in the terminal compartment
of the signal converter. See sect. 2.1.2 for the compact
flowmeters, and sect. 2.2.2 for the separate systems.
❶ Standard grounding of compact flowmeters UFM
400 K / 500 K
PE Protective conductor incorporated in the power
supply cable, see sect. 2.1.2.
❷ Standard grounding of separate system flowmeters
UFM 400 F / 500 F
PE Protective conductor incorporated in power
supply cable, see sect. 2.2.2
MR 02/04 Sensor cables, factory supplied, see sect.
2.2.3 for connection.
1.3.2 Grounding with measuring ground M
This type of grounding must be employed if at least one
of the two following operating conditions occurs:
A If large potential differences occur between
protective ground and electric furnaces or electrolysis
plants.
B If a protective ground conductor is not provided,
e.g. for DC voltage operation.
Observe the following when grounding with separate
measuring ground M:
Do not connect up the protective ground conductor PE in
the terminal box if measuring ground M is connected.
If the AC supply voltage exceeds 50 V
rms
, then the
measuring ground simultaneously acts as the protective
ground conductor (combined protective/functional
ground). Refer to appropriate national codes for specific
requirements for this type of installation, which may
require the addition of a ground fault detection circuit
interrupter.
❸ Grounding with measuring ground M for compact
flowmeters UFM 400 K / 500 K
Do not connect up protective conductor PE incorporated
in the power supply cable, see sect. 2.1.2!
M Measuring ground; ground conductor, cross-section
≥
4 mm 2 (AWG 10) Cu with M6 cable lugs, customer
supplied. Threaded hole in housing M4 by 6 mm.
Pump
Never install flowmeter on
pump suction side (cavitation,
Long pipeline
Always install control and shutoff
valves
Open feed or
discharge
Install meter in low
Open
discharg
Downpipe over 5 m (16 ft) length
Install air valve
downstream of
flowmeter (cavitation).
> 5 m
(16 ft)
PE
MR 02
MR 04
L
max
L
min
PE
M