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VAU_RMA

Modbus TCP client for windows

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Hello, I need a Modbus TCP Client for Windows XP. It should only be used to test the communications setup with my PLC, so it is not necessary that it looks good. Since it will be used only for testing of communication, I am looking for a free program or a program that is free with IO limitations. Do you know of a program that would fit the purpose?

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Modsim32 is free and looks OK: http://www.win-tech.com/html/modsim32.htm

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I found one that was suitable for my purpose; Modpoll by proconX Modpoll Modbus Master Simulator modpoll is a command line based Modbus master simulator and test utility. It is free software. modpoll is using the FieldTalk™ Modbus driver. Modpoll binaries are available for the following operating system platforms and architectures: Windows Linux (x86 32-bit) Solaris (SPARC) QNX Neutrino 6 (x86) It can communicate over these protocols: Modbus ASCII protocol Modbus RTU protocol (default) MODBUS/TCP protocol Encapsulated Modbus RTU over TCP There is also a similar Modbus Slave Simulator Edited by VAU_RMA

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Here is our Modbus Class http://pvbrowser.org/pvbrowser/sf/manual/r...ssrlModbus.html It supports RTU, Ascii and TCP and is portable. HMI SCADA as simple as browsing the internet http://pvbrowser.org

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Hello, I am a beginner in Modbus and I need a Modbus TCP Client. The programs you said before don't fit what i need. I want a useful tool with client and server functions to test communication and develop without hardware (at the moment), Modbus traffic monitoring. Moreover, it should be able to communicate with multiple master and slaves and work with redundant networks (I don't know if this is possible).I have found a lot of free and shareware programs on internet but none of them can work with redundant networks. Do you know of a program that would fit the purpose? or even if it is possible to do something like this? I don't mind if the program is not freeware. More details, I would like to create an scenario with several masters connected to several slaves where I am able to test the communication each other with Modbus TCP. It should be necessary work with redundant networks where every device should have 2 ethernet ports (with differents IP's) in order to availability. Do you suggest anything? Thanks. Edited by fersra

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As far as I am aware Modbus can only have 1 master! RTU certainly!

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I don't know how RTU works and maybe I am wrong but, can a master connect to more than one slave at the same time? Slave opens 502 port for listening request of Masters and if the slave is a Multithreaded server, it could manage a lot of clients or masters. The system architecture is Redundant Slave PLCs with dual NIC's connection to a layer 3 switch to the redundant Schneider Masters PLCs. The PLC servers or slaves have dual redundant communication 2 x NICs for the primary server and 2 x NICs for the secondary server. Each server is connected to redundant switches. On the other hand, The PLC clients or masters have dual redundant communication 2 x NICs for the primary client and 2 x NICs for the secondary client. Each client is connected to the respective redundant switches that are connected the servers. If the any primary PLC fails, the second PLC would take over operation. But I don't know yet how I should manage the commands in order to detect duplicate messages or commands or how I should keep refreshed every couple of PLCs (primary and secondary) Can you think of anything? Thanks Edited by fersra

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A master can connect to many slaves. For RTU I like to keep the numbers to max 4-5 as serial is very slow. As I noted I believe only 1 master per network. For redundant stuff you would have to turn the second master off and only have one polling at a time. I use this by the way - it is not expensive http://www.win-tech.com/html/modbus1.htm

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Hi, ICP DAS USA provides a free Modbus RTU/TCP scada software which is EZ Data Logger. But, the systems requires at least one ICP DAS product connected to system. It is really powerful and straightforward. You can check it out frok the below link. http://www.icpdas-usa.com/advanced_ez_data_logger.html?r=Kaan

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I have found the RSSim PLC Simulator to be very useful. It has a built in VBS engine for manipulation of registers. http://www.plcsimulator.org/

 

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you can get free Modbus TCP client as well as server from www.controlsystemtools.com. They both support almost all the flavors of Modbus & are designed to troubleshoot Modbus communications.

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You can use Indusoft SCADA software for up to 40 hours with the free trial.  It works with Modbus devices.  

There's information on it at the first link below and the software download is the second link.  If you have trouble I suggest you use a virtual machine or emulator.

http://www.icpdas-usa.com/indusoft_scada_hmi_for_desktop_server.html?r=maria

http://www.icpdas-usa.com/software/indusoft-web-studio/version-8/indusoft-web-studio-version-8.zip

Edited by Maria_Lemone

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You can try Modbus protocol tester (master) which is free for download from here:http://www.colwaysolutions.com/modbus-protocol-tester.php
 
For a slave, you can find a Modbus RTU and TCP slave implementation in 'C' source code form at http://www.colwaysolutions.com.
 
Since the implementation is in ANSI 'C' you can port it easily to any controller. 
**Slave supports following 11 function codes.
Read Coils(0x01),
Read Discrete Input(0x02),
Read Holding register(0x03),
Read Input register(0x04),
write single coil(0x05),
write multiple coils(0x0F),
write multiple registers(0x10),
write single register(0x06),
Read exception status(0x07),
Report slave ID(0x11),
Read/write multiple registers(0x17)**
 
The vendor also provides ports to a few popular microcontroller cores like 8051, ARM, Coldfire, Analog devices, Microchip, etc. 
 
Including for some RTOS kernels (OS9, MQX, UC-OS). The library is very lightweight consuming negligible RAM and ROM space.
A slave is not free but the pricing seems to be low. They also provide porting services for getting library ported to your board and working at minimal cost.
 
 
Using Modbus Protocol tester (master) and WIN32(C source code) Modbus slave, you can establish client/server Modbus communication between two different PCs.

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