3 Replies Latest reply on Jun 12, 2014 7:01 AM by user_14586677

    Implementing cypress Repeater Algorithm if the communication is not 100% theorically perfect.

    jhunliam.ung

      Hi everyone,

         

       I am considering implementing Cypress repeater Algorithm for PLC (AN62487). My doubt is if we have 15 slaves and the repeater reaches not just 1 node next to it but 2 or more nodes and if we don't have 100% reach ability node-to-node (less say it could take 1-3 messages before one node reads correctly a message).

         
          According to the explanation of AN62487 document on page 2-3 it seems that if a repeater message reaches 2 nodes ahead of it, the 2 node will stop repeating the message because both receive a confirmation from each other and plus the nodes ahead of these 2 have not received the message yet due to the fact we don't have 100% reach ability.   
         
              
         
          Here I try to explain the scenario trough a scheme:   
         
              
         
          A--B--C--D--E--F--G--H--I--L   
         
              
         
          A wants to communicate with L.   
         
              
         
          A has sent direct message to L, which can't see A, A sends broadcast message.   
         
          B and C receive the broadcasted message from A.   
         
          After direct message to L, both send broadcast message. Both receive a confirmation from each other so they stop repeating the message.   
         
          Now, if none of the further nodes ( D,E, ...) has received the broadcasted message from B and C (bad luck), the message is lost and never reach L.   
         
              
         
          My question is: Does the algorithm works if a node next to another does't received with 100% certainty a message.     
         
          Thank you in advance for the support.    
         
              
         
          - J