Modbus Router

M

Thread Starter

ModbusChris

Dear Forum

I have a question concerning Modbus TCP IP.

There is a network with three servers, each with its own IP, that provide data via Modbus TCP as slaves. I have a Software that should read the information in that network as a Master, but it can only access one IP address.

So am looking for some sort of Modbus Router that can read as a Master via Modbus TCP data from the 3 Slaves each with its own IP address and that then can give out the read data via Modbus Slave (or Master if Slave is not possible) on a single IP address.

The idea is to bundle the information from 3 IP addresses to just 1 IP address. Then my Software can read the data properly.

Does anyone know if there is hardware (or software) available that can do this?

Thanks a lot in advance for an answer,
Chris
 
> So am looking for some sort of Modbus Router that can read as a Master via Modbus TCP data from the 3 Slaves each with its own IP address and that then can give out the read data via Modbus Slave (or Master if Slave is not possible) on a single IP address. <

Our MBRG-300 router/gateway would be able to do this. It acts as intermediate gateway exposing one single IP address and you can map other Modbus/TCP slave devices to be accessible either under different register ranges or under different slave IDs.

So you could map 192.168.1.11 registers 1000 to 1999 to be accessible as 192.168.1.1 register 11000 to 11999 and 192.168.1.12 registers 1000 to 1999 to become 192.168.1.1 register 12000 to 12999 and so forth.

http://www.proconx.com/modbus-router-gateway

Regards,
Henrik
http://www.proconx.com
 
G

Gabriele Corrieri

Hello,

have you idea how to discriminate slave 1 of first server from slave 1 of second one?

An idea could be assigning modbus addresses different: in that way could be only one slave 1 ...

Could you modify the configuration of the servers?

In that case you must write another piece of software for bringing together the three logical networks ...

I'm interesting to know how it will be resolved.

Regards
Gabriele Corrieri
 
M
That's an interesting question.

I understood that it's done via the register address range and therefore is not a problem?

Kind Regards,
Chris
 
question: > how to discriminate slave 1 of first server from slave 1 of second one?

Answer: >3 Slaves each with its own IP address

A unique IP address is used for each slave.
 
Hello Gabriele and Chris,

The proconX MBRG-300 router/gateway can re-map slave IDs and also start register ranges (and even function codes).

Using that feature, the master can see the three slave's register range using one of the two re-mapping schemes:

a) Keep start registers the same as the original slave device BUT discriminate them using the slave ID (also known as unit ID). So the 3 Modbus/TCP slaves are all accessible under one IP address but using different slave IDs. The MBRG-300 remaps a request received for 192.168.1.1 slave ID 2 and sends out a request to 192.168.1.12 using slave ID 1 and then maps back the slave ID for the reply.

b) Use a single IP address and a single slave ID but have the registers re-mapped into different register regions. The MBRG-300 remaps a request received for 192.168.1.1 register 2000 and sends out a request to 192.168.1.12 using start register 1000 and than maps back the reply into the original range.

Regards,
Henrik
http://www.proconx.com
 
Chris,

Real Time Automation offers a solution for you. It is the 460MCMS-N34-D. The gateway acts as the Client for your three Server (Slave) devices and then as the Server(Slave) for your software program. It grabs the data from the three Servers and then will present it as data from a single Server to to the Client (your software). Here is a link for more information:

http://www.rtaautomation.com/product/460mcms/

Gateway's setup is very simple. It is a web interface, where you enter in the IP Address of the gateway into a web browser (Chrome, IE,etc.). From this, you are able to set up your IP Addresses, scan lines, registers, etc. It also has a Display Data page that shows the mappings and the data being pasted through it. Also, it is priced great, which is an added bonus.

Matt
 
M
Thanks a lot for all the answers and provision of working solutions.
That's very much appreciated.

Could I ask one additional question please.

Would any of the above mentioned solutions also provide the capabilities as described above and then also offers the possibility to write (log) the read data to a text file?

The reason for this is that we have problems with the Modbus connection with our software (seems to be a float / int problem). If we could have the data as a text file, then we could read that with our software and we would have a preliminary working solution at least to start with.

I hope that makes sense,

Kind regards,
Chris
 
Modbus is responsible for packing binary bits into a specified format and transporting them from slave to Master or vice versa and for generating some basic error codes in the case when transport part doesn't happen as expected.

The interpretation of the received data is up to the application software/firmware on the receiving end. Once the binary bits are interpreted as data values (whether integer or floating point), what is done with them is up to the application.

Saving data values as ASCII numbers in text file might be an application option (depending on the resources available), but it is not a Modbus function. Modbus is only responsible for transferring the data as binary bits. Interpreting the bits into useable data and what happens with the data is up to you or the application software claiming to run the Modbus data transfer function.
 
Chris,

>Would any of the above mentioned solutions also provide the
>capabilities as described above and then also offers the
>possibility to write (log) the read data to a text file?

Within the RTA 460MCMS, there is no output of a log. However, there is internal Logging within their Diagnostics that will show the requests, successful transmitting, etc. I don't believe that is what you are looking for, but this would at least let you know what is being sent.

Matt
 
Here is a solution that I believe would work for you:

1. The ICC ETH-1000 gateway (http://www.iccdesigns.com/millennium-series/10-eth-1000.html) provides the ability to map Modbus RTU to /from Modbus TCP. The gateway includes all drivers for free: this includes all the Modbus drivers (master, slave, sniffer etc), as well as all other Ethernet-related drivers (PROFINET, BACNet/IP, EtherNet/IP etc.) All Ethernet drivers can be active simultaneously, which can be useful if you ever have a need in the future to transition to additional non-Modbus client devices or switch networks completely. Configuration is done with a free Configuration Studio software package, so you can create a complete configuration prior to owning a device. All configuration activity is accomplished via USB.

2. For logging data values, you can use the free ICC Modbus Master Tool on a PC (http://www.iccdesigns.com/software/43-icc-modbus-master-tool.html). This free software can communicate via Modbus/TCP to the ETH-1000 above (in parallel with your existing client) and log data to a CSV file. This file can then be opened in Microsoft Excel, etc. There are a series of YouTube videos (https://www.youtube.com/playlist?list=PLsV5cTr-4yCmdg67f03QtnLD7dmebDLxv&feature=plcp) that document the configuration and use of this free software.
 
Chris,

Please check out ICLinks.com. They have a simple device/PLC/RTU that should do it for you no problem.

It will master the remotes and map to registers for you master to poll it, Data log and create CSV/Excel reports. Graphics, trend and alarm, logic,etc.

Let us know if you need help
Mark
 
Hi Chris,

You can use our PMC-5151. This module can poll up to 8 different Modbus TCP devices. You will need to set up the registers to poll in the module to poll along with the IP of your slave devices. The PMC will continuously poll the slaves and store data in it's shared memory table. Then, you can poll the PM-5151's shared memory table via Modbus TCP to get data from all of your devices.

<pre>http://www.icpdas-usa.com/pmc_5151.html</pre>
 
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