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Problem with termination in Profibus

Created by: Krzychu at: 11/20/2009 12:17 PM (4 Replies)

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11/20/2009 12:17 PM	Rate (0)
Krzychu Posts: 11 Rating: (0)	Hi I have optical ring build on OLMs. To each OLM I have connected IM-151 modul and for one PLC S7-3152DP. My question is should the termination on electrical cable between IM-151 or PLC and OLM be on or off. Best regards, Krzysiek
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11/20/2009 2:46 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 12/6/2024 Posts: 12301 Rating: (2691)	Hello Krzychu; This is an extract from the Simatic Net Profibus OLM operations manual, v. 4.0, in the secction concerning the setup of the RS-485 branches on the oprtical ring: http://support.automation.siemens.com/WW/view/en/24164176 In order to minimize disturbances, keep to the following order when connecting an RS-485 bus cable to a PROFIBUS OLM when the network is active: 1. Plug the RS-485 bus connector onto the relevant device (e.g. the programming device) and secure it with the screws. 2. Insert the RS-485 bus connector in the PROFIBUS OLM with a sharp movement and without tilting the connector. Carry out the steps in the reverse order to disconnect a device from the network. 􀂾 Make sure that the bus segment connected to the RS-485 port is terminated at both ends. Only use a connecting cable that is terminated at both ends to connect a single device. 􀂾 If temperatures in excess of 70 °C can occur on the cables or their insertion points or the temperature... Hope this helps, Daniel Chartier

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11/22/2009 11:59 PM	Rate (0)
mumbles Posts: 160 Rating: (16)	Every new copper electrcial segment need to be terminated at each end. So if the OLM is at one end the termination needs to be applied here as well as the IM at the other end. Any devices configured in between do not need to be terminated. To put it simply if your PLUG has only one cable in it then you need to apply the termination.
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11/23/2009 8:36 AM	Rate (0)
how come Posts: 382 Rating: (47)	Krzychu Hi I have optical ring build on OLMs. To each OLM I have connected IM-151 modul and for one PLC S7-3152DP. My question is should the termination on electrical cable between IM-151 or PLC and OLM be on or off. Best regards, Krzysiek Hello Krzychu, I hope I can understand your question. Are you talking about the profibus connector switch position? Hope the below example are useful to you 1] Profibus connection andresistor switch position: [PLC DP port --------to-------OLM1 profibus port] a]profibus connection A1B1-------------------to--------A1B1 b]connector switch position (ON) (ON) [OML2 profibus port--------to------- IM153-1] a]profibus connection A1B1------------------------------to--------A1B1 b]connector switch position (ON) (ON) [OML3 profibus port --------to------- IM153-1] a]profibus connection A1B1------------------------------to--------A1B1 b]connector switch position (ON) (ON) 2] Ring connection from OLM1 to OLM2 to OLM3 and back to OLM1 using fiber optic:- OLM1 [ch3] --------connect to-------- [ch2]OLM2[ch3] --------connect to-------- [ch2]OLM3[ch3] --------connect back to-------- [ch2]OLM1. 3] Dip Switch Setting for Ring connection ForOLM1, OLM2 &OLM3 S1 to S6 switch to position 1 S0 And S7 remain as position 0 Hope these helps! with regards, how come
how come Posts: 382 Rating: (47)
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11/23/2009 9:07 AM	Rate (0)
Krzychu Posts: 11 Rating: (0)	Hi Everyone Thanks for help:)
Krzychu Posts: 11 Rating: (0)
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