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Electrical connections – KROHNE ALTOSONIC V12 EN User Manual

Page 28

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4

ELECTRICAL CONNECTIONS

28

ALTOSONIC V12

www.krohne.com

04/2013 - 4002643502 - MA ALTOSONIC V12 R02 en

4.4 Serial data communication (RS 485)

4.5 Power connection

Figure 4-5: Connection of serial data communication

INFORMATION!
For more information about Modbus, refer to Modbus protocol description and set-up on page
111

.

WARNING!

Use a 24 VDC power supply to power the flowmeter, which complies to NEC class 2 (max. 100
VA, 24 VDC

±

10% , see also IEC 61010-1, clause 6.3.1 and 6.3.2). The maximum power

consumption is 17 W. The power supply must be able to supply 3 A (needed during start-up).

The protective earth conductor (1...4 mm

2

, AWG 17...AWG 11) of the power supply must be

connected to the protective conductor clamp terminal size M5, which is press-fitted in the
terminal compartment.

Use a cable entry to lead the power supply cable to the electronics. The power delivered from
the power converter inside the unit is limited to a maximum of 15 W according to the

fold-

back

principle (when the admissible internal power consumption is exceeded the delivered

power is reduced to zero). Separately the current consumption is limited to appr. 1A.
Requires typically 3 x 1.5 mm

2

(AWG 15) conductors.

Connection to a flow computer, a data acquisition system or process control system by
means of digital output signals; requires as a maximum 4 pairs of wires of 0.75 mm

2

(AWG

18) copper each.

Connection by means of a RS 485 data line to a device for logging or monitoring data or
running a software service tool for performing a function check or a service jobs; requires a
shielded pair of two twisted conductors of 0.75 mm

2

(AWG 18) copper each.

Connection to a data acquisition system by means of digital signals; requires a shielded pair
of two twisted conductors of 0.75 mm

2

(AWG 18) copper each.

Connection to safety / protective ground (earthing) ; requires insulated wire, minimum copper
cross section area 4 mm

2

(AWG 11).

INFORMATION!

The protective conductor clamp or GND of the connector can be used for the shielding of the
cable.

The electronics is protected against connecting a power supply with the wrong polarity.