Plc s7-300

dear all


since i m still newly expose too this...i have couple of question that i really need answer ,so that i can sure either the configuration of wincc 2007 (pg/pc interface)..

1) i saw 2 com port at cpu ..this cpu are (cpu-313C-2DP)..and i have 2 number of socket with 2 number of cable. 1 socket at PC and other socket at cpu which 1 of the cabel are connect other side..problem i m facing this ..the former guy who do this had dismental due to his mentality problem..and had open all the wire at socket...somehow i manage too hook 1 cable and run this system too manual..but unable to run VIA wincc (pc)..my big question..how do i connect the cable and how too set the on /off switch at the socket..there 2 set of terminal address as A1 Green B1 Red and A2 Green B2 Red...which terminal i should connect at PC side and which terminal i should connect at CPU site.

2) what is the diffrent of profibus and MPI connector ..and where can i find this catalog or manual of it ..

i m really sorry for such long post..and i really hope some1 could help me on this so i can move too next step ..please let me know if there any other information needed.

You Profibus connectors have arrows on them to show that A1 & B1 are for your incoming cable and A2 & B2 are for the outgoing cable if you have further devices on your network. The plug on the first and last device on your network should have the resistor switch set to the on position. Some devices can have selector switches or other means to do this. A HMI screen can usually either communicate to the PLC by either MPI or Profibus. The MPI port should be the left hand programming port as you look at it and the Profibus would be the right hand one.

dear sir ...is the attacthment of the socket and arrow that you mention are what you mention on ur mail.if please can you let me know how does this connection currently i made coonection at PC on A1 and B1 and the other connection i connect at CPU on A2 and B2 and the switch are set as off..and on the cpu as the same socket i connect A1 and B1 too feild other side

If you have 2 devices, a cpu & a HMI screen then you would use a single cable to connect them. The ends of the cable should be connected to A1 & B1 of both plugs and the terminating resistor should be switched on for both plugs. Its just like a simple circuit, the cables go in on A1 & B1 and if there is a cable going out somewhere else to an additional device the other cable is connected to A2 & B2 and your switch would be off. Turning on the switch isolates the connection to A2 & B2 thus terminating the loop at that plug. To program the cpu through the Profibus you should use at least 1 'piggy-back' type connector with a 9 pin D-sub plug on the back so you can connect your programming cable onto the network.

thanks ..i will try too make the connection as you recoommend and on the CPU i do have piggy back connector as you mention..i would take pic of you after connect ..and send here..