Inhaltsverzeichnis
1
RS485-Bus ....................................................................... 3
1.1
1.2
1.3
1.4
Zeitverhalten .................................................................................3
1.5
2
Modbus-Protokoll ............................................................. 4
2.1
2.1.1
2.1.2
Wartezeit ......................................................................................4
2.1.3
Funktionscode ...............................................................................4
2.1.4
Daten ............................................................................................5
2.1.5
Error-Check ...................................................................................5
2.1.6
2.1.7
Fehlerbehandlung ..........................................................................8
2.2
2.2.1
Adressierung .................................................................................8
2.2.2
Format ..........................................................................................8
2.2.3
2.2.4
Parameter lesen ............................................................................9
3
3.1
Telegrammaufbau .......................................................................10
3.1.1
3.1.2
Formate ......................................................................................10
3.2
Meldungsinhalte ..........................................................................11
3.2.1
3.2.2
3.2.3
3.2.4
3.3
Beispiele .....................................................................................13
3.3.1
3.3.2
4
4.1
Allgemeines ................................................................................14
4.1.1
Anschluss ...................................................................................14
4.1.2
4.1.3
4.1.4
4.1.5
Datenaustausch ...........................................................................14
4.2
4.3
4.3.1
Funktionsfeld ...............................................................................16
4.3.2
Blocknummer ..............................................................................16
4.3.3
Checksum ...................................................................................16
4.3.4
4.3.5
4.3.6
5
Wortadressen ................................................................. 22
2
Seite
GMC-I Messtechnik GmbH