CARLO GAVAZZI UDM 40 - PROGRAMMING Instrukcja Użytkownika Pobierz pdf (Strona 23)

CARLO GAVAZZI

CONTROLS

SERIAL COMMUNICATION PROTOCOL

UDM - USC

V1 R1

Page

not connected, faulty or having a different address. The same consideration is valid in case of

CRC errors or incomplete frames.

2. By entering the programming mode (by pressing the “S” key) the communication is interrupted.

Any data received during the programming mode are ignored.

3. To avoid reflections or couplings between the communication wires it is suggested to terminate

the last instrument of the network and of the host. If some problems persist, bias the host

transmission. It is advisable to terminate the network also in case of short point to point

connections.

4. If the connection is longer than 1000 m a signal amplifier has to be used.

5. To calculate the time required to scan all the instruments of a network, the following formulae

are to be used:

Trequest

N bit

Baud rate

Treply

N bit

Baud rate

N char=

request

response

delay

request

(

)

sinstrumentNTdelayTSTM °+= *2

N° bit 10 (no parity), 11 (even or odd parity)

N° char 5 + number of Words*2 (function 04), 8 (function 06)

N° word Number of words to be read in the same request

TS Reading execution time

Tdelay1 Minimum time for a new query on the same address

TA Instrument data acquisition time

TM Total network scanning time

N° instruments Number of instruments connected in the network

Tdelay2 Minimum time for a new query on a different address

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CARLO GAVAZZI UDM 40 - PROGRAMMING Instrukcja Użytkownika Strona 23