Hi,

I was studying the Mobus sample project zXX21_04_PtP_Com_MODMA\Modbus Master available in STEP7 Simatic Manager .

 I came across this surprise cross reference list ( Menu Reference Data / Cross references) to 

      Input   bit  : I0.0 ,

     Output bit : Q0.0

     Memory  bit : M0.0

in the Siemens Protected FB7  P_RCV_RK. (Please refer to page#2 of 2 in the attached pdf of the print out of the cross reference list highlighting this.)

I think it is a bug. Can some expert  confirm it ,please ?. It shakes my confidence if it is really using these bits in the Proetected FBs and the user is unaware of this. 

From a Beginner 

Kamath RL

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Split from S7 Cross Reference Data.