Operation & Installation Manual V12-V6 2010-05-31.doc
31/05/2010
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5.3.4. Serial communication (USB)
NOTE!
This port is only available when electronic housing is open..
A serial port (USB 2.0) is provided for connection to a notebook PC. This is a
service/maintenance connection to be used only by the factory or technicians authorized by
Krohne. The initial parameter set-up is programmed into the flow meter by means of this
serial connection. Entering or overwriting parameters with incorrect values will cause serious
problems regarding the functioning of the flow meter.
As soon as the meter has left the factory and has been installed in the field it is
recommended to use one of the RS485 serial ports (see par.5.3.3) for monitoring the flow
meter or in order to make modifications to the parameter set-up, if required.
5.3.5. TCP/IP communication
NOTE!
This option is only available when electronic housing is open and using a signal cable with a
special interface. This is also service/maintenance connection to be used only by the factory
or technicians authorized by Krohne. When the meter is installed in the field it is
recommended to use one of the RS485 serial ports (see par.5.3.3). for monitoring the flow
meter or in order to make modifications to the parameter set-up, if required.
5.4 Cabling
For connecting power and the digital outputs as minimum one cable can be used, two
separate cables may be used as there are two cable glands available. An unused cable
gland shall be removed and replaced by an Ex-d blind plug.
We recommend to use screened cable with twisted pairs for connecting power and the status
signals. The screen may be used to connect the ground terminal.
In order to limit the voltage drop across the power wires to an acceptable value, the copper
cross section shall not be less than the value according to the table below (assuming no
other components - such as safety barriers - add any additional voltage loss):
Length of cable
between power
supply and ultrasonic
gas flow meter
Required
minimum copper
cross section
70 m
2 X 0,5 mm
2
100 m
2 X 0,75 mm
2
200 m
2 X 1,5 mm
2
400 m
2 X 4 mm
2
For connecting the serial data outputs as minimum one cable can be used, two separate
cables may be used as there are two cable glands available. An unused cable gland shall be
removed and replaced by an Ex-d blind plug.
We recommend to use screened cable with twisted pairs for connecting the serial ports. The
twisted pairs may be screened individually or both pairs may have one and the same screen.
The screen(s) may be used to connect the ground terminal(s).
