7 serial interface rs232 / rs485 – WIKA DI35 User Manual

Page 26

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6 Commissoning, operation

26

WIKA operating instructions digital indicator DI35-M

6.3.7 Serial interface RS232 / RS485
If the DI35-M has an serial interface, the device can be programmed via this
interface. The interface is available as an option, the basic version is without
an interface.

Operating mode:
The interface can be operated in various modes which can be parameterized
via the PN34 (interface behavior).

Parameter Description
PN34 = 0

Standard mode in which the unit only replies if called on to do
so. This mode is used only for configuration. Furthermore the
current measuring value can be recalled via commando “A

↵ “.

PN34 = 1

Transmission mode in which the measurements are
transmitted via the serial interface cyclically with the set
measuring time.


The transmission mode is interrupted on receipt of “>

↵“ and the unit changes

to standard mode. To change back to transmission mode, the display must be
restarted, either by entering the command “S

↵“ or by switching the device off

and on.

With the transmission mode, the display value is transmitted via the interface
in ASCII format. Minus signs and decimal points are also transmitted so that
the output can be displayed directly on a terminal or processed by a SPS.
Zeros at the front are suppressed during transmission. With an over or
underflow, the display transmits horizontal bars (hyphens) "- - - - -

↵".

If there is a broken wire detected at temperature measurement "Lbr

↵ " will be

sended. A choosen dimension ("°C" / "°F") will be ignored at transmission.

Examples: "0.00

↵" ; "-9.99 ↵" ; "999.99 ↵" ; "-123.45" ; "- - - - - ↵“ ; "Lbr ↵"


With the aid of this simple protocol structure, the display data can be
transferred very easily to a PC etc. and further processed there. In the
simplest case, a terminal program from the operating system is sufficient to
store the received data in a file .

Configuration of the device via interface
For configuration the set-up tool PM-Tool can be used. As the communication
is a straight point-to-point connection. The baud rate is set to 9600 baud, with
8 databits, without parity and one stopbit.
Configuration is performed by transmitting ASCII symbols.

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