CommunicationABB Control - AC 31 Page 7-131SBC 260400 R1001-b 06.992. Point to point communication with the incorporated ASCII interface2.1. Protocol descriptionASCII communication is a protocol which enables exchanging text coded in ASCII (AmericanStandard Code of Information Interchange) between two devices for example.It may be used by the 40 and 50 series central units to communicate with a printer or aterminal fitted with an ASCII interface (Figure 7-7).2.2. Configuration of the communication2.2.1. Using the black 07 SK 51 or 07 SK 53 cableThe serial interface of the 40 and 50 series central units is configured by default inprogramming and test mode with the grey 07 SK 51 or 07 SK 53 cable and in MODBUSmode with the black 07 SK 51 or 07 SK5 3 cable.Changing the programming mode to ASCII mode requires a serial interface configurationthrough the software: Click on the "Launch PLC configuration tool" icon in the AC31GRAF control windowand select "ASCII" or "Standard" from the list of the "Communication mode " line (seeFigure 7-8).ASCII mode is available when the central unit is running. Programming mode is, once again,available for test or modifications once the central unit program is stopped or when the grey07 SK 50 or 07 SK 52 cable is used.Comments:When the central unit program is running:- Choosing "ASCII" validates the communication whichever cable is being used.- Choosing "Standard" validates the ASCII mode with the black 07 SK 51 or 07 SK 53 cableand the programming mode with the grey 07 SK 50 or 07 SK 52 cable.2.2.2. Communication parametersThere isn’t a default configuration. It is therefore necessary to configure the communicationparameters (speed, stop bits, data bits, parity, end of frame) with the SINIT function in theuser program.
