I need to find a resource to interface php with modbus/TCP, Is there anybody know a resource?

 

Hi,

Could you tell if your platform is Windows or Linux? If Windows, then there is a way to interface a dll into a PHP script. You can find many implementations of MODBUS in the form of a dll from various vendors.

If Linux, I am not too sure at the moment. Thanks.

Regards,
Ganesh Okade
Sunlux Technologies Ltd.
http://www.sunlux-india.com

 

There are free modbus/TCP drivers available. I will let others recommend particular libraries, but you can perhaps use the ones from pvbrowser (http://pvbrowser.de) or MAT (http://sourceforge.net/projects/mat/).

In either case, you will end up with a C library that you need to interface to PHP. Below are some URLs which show how to do this in the general case.

http://www.php.net/manual/en/zend.creating.php

http://www.zend.com/php/internals/index.php

 

I've got a fairly generic modbus library written in C for linux at

http://www.seiner.com/ts7000/index.php/Modbus_and_Serial_Comm

It's GPL, so please read and understand the benefits and restrictions that places on the code use.

I am working on a TCP wrapper now; if anyone would like to contribute, please feel free.

Mostly it needs testing and debugging.

--Yan

 

I have a program called Modserver on Linux (Fedora, Suse). It is very reliable.

The whole system structure

PHP
|
Modservre
|
SCADA, PLC

-----------------------------
http://www.icscada.ca

 

In reply to Roy Yin: I had a look at your web site as I was curious, and noticed your mention of "XML Modbus protocol", "XML Modbus command", and "XML Modbus message". Is this just your way of describing an implementation of a set of web services, or is there actually some formal "XML Modbus" standard that I haven't heard of?

 

Modserver is a service program, just like OPC server. To control a RTU, C, PHP, or any script language connect to Modserver by using TCP socket or Unix Socket, and send XML format command to Modserver. Modserver parses the XML command, optimizes , creates a RTU acceptable Modbus command, and sends to RTU. It will format the response from RTU to readable XML format, and send back.

To write 25.4 register 40179 on slave 15
<modbus tranid="1"
unitid="15"
address="40179"
number="2"
function="16"
datatype="float"
byteorder="DCBA"
data="25.4" />
and response:
<modbus tranid="1" function="16" data="" state="0" />

-------------------------------
http://www.icscada.ca