Modicon M580 Plc Page 3-16 Communication

3/16 Modicon M580 automation platform Ethernet Modbus/TCP network Performance Application response time (continued) I/O Scanning service response time The response time RT includes the time between taking account of information from a remote input and updating the state of a remote output. It includes the processing time in the PLC. This response time RT consists of the following parameters: v TMod In and TMod Out: Response time of the read/written device, excluding the electrical transition time at the input/output (TMod depends on the device, usually between 1 and 8 ms) v TIOS In and TIOS Out: Time between 2 read/write operations on the same device (0.3 ms x number of devices scanned), at least equivalent to the configured scan time As TIOS is executed in parallel with the PLC cycle, it can be hidden from the viewpoint of the response time (RT). v Cycle T: PLC scan cycle time v TNet: Propagation time on the network (depends on the application, but usually TNet = 0.05 ms at 10 Mbps and 0.005 ms at 100 Mbps) The response time RT can be estimated using the following 3 formulae: b RT min , minimum response time with TIOS hidden and 1 PLC scan cycle: b RT typic , typical response time with 0.5 TIOS hidden: b RT max , maximum response time with TIOS not hidden: RT min = (TMod In + 0) x TIOS In + (Tnet + N) x cycle T + (0 x TIOS Out) + Tnet + TMod Out RT typic = (TMod In + 0.5) x TIOS In + (Tnet + N) x cycle T + (0.5 x TIOS Out) + Tnet + TMod Out RT max = TMod In + TIOS In + (Tnet + N) x T cycle + TIOS Out + Tnet + TMod Out Performance (continued) I/O Scanning service response time Device 1 Device 2 Manager Hub Input Output CT RT Ethernet Modbus/TCP Response time (RT) Input Output TMod In TMod Out TIOS In TNet N x Cycle T TIOS Out TNet Processors: page 1/20 I/O architectures: page 2/2 Ruggedized Modicon M580 modules: page 4/2 2 1 3 4 5 6 7 8 9 10 2 1 3 4 5 6 7 8 9 10

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