MODBUS RTU Vs MODBUS Remote

[Anthony96]

I contacted Automation Direct about the DL06 to inquire about Modbus RTU (not to familiar with it). The tech I spoke with said that as long as Fix 32 had this Modbus RTU driver I would be fine. I then researched Modbus RTU (Remote Terminal Unit) and found that it seems to be an 8-bit serial interface. I then went into my Fix 32 software to locate this driver, however the only ones similar in name to this were Modbus Ethernet, Modbus ASCII (7-bit serial), Modbus Plus and Modbus Remote.

Are Modbus RTU and Modbus Remote the same and Intellution simply left off "Terminal Unit" or not? If they aren't, what do I do to interface the DL06 with Fix 32.

Thanks.

[Jim Dungar]

For serial communications there are only two Modbus choices. So if it is serial and not Modbus ASCII it has to be Modbus RTU.

[Anthony96]

Alright, however, I wanted to know if Modbus RTU and Modbus Remote are the same thing. Or, does anyone possitively know if the DL06 will work with Fix 32 since I am going to purchase one if it does. However at $450 I want to make sure.

Thanks.

[Steve Bailey]

Have you tried contacting the person from whom you bought your Fix32? Modbus RTU is the more commonly used term. I've never heard it called Modbus Remote. If they're going to make up their own names for protocols, they ought to be able to translate those terms to the vernacular.

[akreel]

Originally posted by Anthony96
Are Modbus RTU and Modbus Remote the same and Intellution simply left off "Terminal Unit" or not? If they aren't, what do I do to interface the DL06 with Fix 32.

I think you might want to contact Intellution. But, it sure sounds like you've got the right idea. All of the other drivers you listed are definately your basic flavors of modbus.

What do you do if they aren't the same? Doesn't the DL06 support Modbus ASCII, too?

AK

[Mickey]

Yes they are different. Modbus Remote (MBR) is generally used for Radio, Dial-up or direct connection.
Modbus driver (MB1) can be ASCII or RTU mostly used for direct connection but can be used with modem.
You can download these drivers from GE web site


http://www.gefanucautomation.com/default.asp

Hope this helps

[Ken Moore]

From the Intellution web site:

[akreel]

"No FAQs for this driver"

That's funny, considering the current situation.

[Jim Dungar]

The way I read the GE info is: The GE driver MBR contains both the Modbus RTU and the Modbus ASCII protocols. The important part is that GE requires 7 bits.

Modbus RTU (from Modicon) is 9600, 8, E, 1 but all of the parameters are adjustable.
Modbus ASCII (from Modicon) is 2400, 7, E, 1 but again the parameters should be adjustable.

[Anthony96]

Thanks Ken, I have been on that site and I guess it didn't register to me that those were "TABS" up there with additional information. That answers my question. Like I said in my "Senior Design" post, I am new to this and I appreciate everyones willingness to help.

No FAQs about this subject, yeah that is funny. I have been asking questions all day about this.

Thanks.

[irfanbashir]

Hi,i want to need your kind help in my working project
i have modicon M340 and 4 SEL 751-A relays i want to communicate each other through modbus RTU.
now i want just read simple values from SEL relay and show on my SCADA screen.but problem is that i have 125 register in SEL Relay and i want to read only 14 values like power,current,voltage and frequency.i am little bit confuse in FBD coding
firstly ADDM reg in FBD here we mention the slve addres of SEL Relay and then Read variable in here how i can read specfic reg value...like in SEL relay at MODBUS reg addres is 586 for currnt value how i can get this reg value.....any one help me please?????????????????????

[boxofrelays]

Modbus RTU lends itself to reading single words (16 bits) or multiple, contiguous words from different Modbus slave nodes, in your case these slave nodes are the SEL protection relays. First thing I would do is get a free Modbus reader (http://www.chipkin.com/technical-res...odbus-scanner/ ) to see if the values you're getting from the SEL protection relays are what you want, for example if the SEL protection relay works, and if the values are 16-bit integers or floating numbers. -Chris