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bjump

S7-200 modem communcations

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Hello all, I have an S7-200 that I am trying to connect to a modem via a PPI cable. The radio attached to the modem will key its transmitter upon receiving the RTS signal from the PLC. The problem I am having is, as soon as I switch the PPI cable to DTE, which allows it to utilize the RTS signal, the radio is in continuous transmission. This leads me to believe that the PLC/PPI cable is constantly sending a RTS signal to the modem. Would there be any cause for the PLC to do so? Is this a flow control issue? Please help.

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Why not just get the modem module which goes right into the S7-200 expansion bus? There's a wizard in the software to make configuring it very easy.

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The customer is replacing over 90 of the old Modicon Micro's with S7-200's. Therefore, buying over 90 new modems is not an acceptable solution.

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Hi: May Be When You Turn Off The Switch,The Signal's Status Will Keep some times,the reason is the Modem's Scan Cycle is more short than the RTS signal Send Cycle! Problem will be familiar in Serial Port Program Design! Luck Edited by JOHN F NASH

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