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Siemens CIM+Logo8 cyclic modbus RTU but i want single R/W register commands
Created by: AutoGen_2602752 at: 4/17/2025 11:29 AM (1 Replies)
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| 4/17/2025 11:29 AM | |
Joined: 4/17/2025 Last visit: 4/22/2025 Posts: 1 Rating:
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Good day time dear Siemens support and engineering community. I am a student-electrical engineer in Netherlands. I am doing internship in University on the topic of industrial automation so i dont know all the abbreviations). We are currently integrating good Siemens CIM module[6ED1055-5MC08-0BA2] in pair with Siemens Logo 8 PLC in order to read multiple industrial sensor values via Modbus RTU RS-485 network for water quality measurement system. As hardware/PLC-software designer-student I want to get the variable e.g . measured value from sensor to the PLC logic, however i figured out the CIM has cyclic communication(see picture 1 as on example from [https://support.industry.siemens.com/cs/document/109806055/logo!-cim-modbus-rtu-communication-with-sinamics-v20?lc=en-de]). But my system comes with special Ultraviolet sensor where I must once per minute trigger the measurement via Modbus registers and only after a minute UVsensor will be able to "answer to" Read registers command to get the measured UV sensor values array. Alongside In the same RS-485 network another Mobus RTU sensors CIM in my project must read the value more frequently(1th per second for example). The question is: 1. Can you please explain or give example of how can i can setup Siemens CIM or Logo PLC code so CIM triggers SINGLE Read/Write Modbus register command once as per "function call" from Siemens Logo 8 PLC code please? 2. According the CIM web interface config instructions i should use CIM "Data bindings" configuration for this(see picture2 screenshot taken from CIM web interface cfg manual page 39.pdfand PLC Boolean trigger variable in PLC code via S7 network right? 3. Then my 3rd question is: if i will switch off "Customized intervals" (see picture 3) in Modbus RTU data transfer table setting of "Siemens CIM", & then by Data bindings configurator in web interface I will change CIM internal memory speially declared boolean variable(network vairable S7) by PLC logic via S7 network) will CIM be able to send Modbus RTU read/write register command to the sensor only ONCE by trigering-variable (if mentioned Modbus customized intervals in CIM are being switched off)? This is important for my internship project since my sensors have volatile flash memory that can't be overwritten every second. P.S Yes i know that i could change plc to other type and code it with codesys but it is not desired by my internship boss)) and i not guru of codesys with my short exp.) Met vriendelijke groet, Student intern.
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