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10/27/2008 11:37 AM | |
Posts: 2930 Rating: (432)
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Hi, I had a same case in teh past. How do you power the OP77 and what kind of communication cable do you use between the OP77 and the PLC? Background: The OP77 can be powered seperatly (using the 24V DC connector). In this case you have to use a Profbus cable to connect the OP77 to the PLC, otherwiseyou power the OP two times. If you use a cable between the OP77 and the PLC with 9-pin-SUB-D and all pins are connected, then the OP77 is powwered by the PLC interface. If youpowerthe OP77 additional with the 24V DC connector then you have two time power at the OP. This is not allowed. Use the serate 24V DC to power the OP77OR the power from the PLC interface. More information you can find in: the OP manual http://support.automation.siemens.com/WW/view/de/21084916 the S7-200 manual http://support.automation.siemens.com/WW/view/de/1109582 I hope this helps Regards Helmut |