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How to read cFP-1804 AI channel with modbus I/O server

How to read cFP-1804 AI channel with modbus I/O server

I recently purchased a cFP-1804 with cFP-AI-100, cFP-AI-110, cFP-TC-120 modules for data acquisition with the understanding that it will communicate via modbusTCP. 

I am using a Wonderware HMI and Historian with Universal I/O Server and would like to set up to monitor and store the values.  I need the 6 digit Modbus address from the cFP to set up the tags in the HMI and the Historian.

Is the cFP configuration stored in the cFP unit once it has been configured in MAX?
How do I find the modbus addresses for the channels in the cFP?


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Re: How to read cFP-1804 AI channel with modbus I/O server

The scheme for mapping your FieldPoint I/O channels to a Modbus address is described in a help file installed with your FieldPoint software.  Look in your "<National Instruments directory>\FieldPoint\documentation\Online Help\", and there should be a help file called FPModbus.chm.  It is fairly straitforward to do the mapping if you are famiar with the Modbus protocol.  If that document doesn't explain it, then let us know what channel on which module you are trying to read/write and someone will be able to help you with the address mapping.

-Tommy
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Re: How to read cFP-1804 AI channel with modbus I/O server

I see the addressing method in the help file.  I set up the circuit and device and can see that it is making transactions but I am not able to display actual values.

I haven't been able to determine if the address is incorrect or if I don't have a correct setting in the modbus functions.

I tried address for an cFP-AI-100 in slot 1 of 31000 to 310016 for the scaled values (0-30000 psi) and 1000 to 1009 for the pre-scaled values (0.0035-0.024 amps).  I end up with 0.00 in my HMI display.

The I/O server has multiple settings.  According to the help file, addresses in the 30001 to 39999 should be 32 bit, 2 address.  It doesn't give further detail to say if it is integer signed, unsigned or real float value.

Is there more information for the modbus function settings?

Thanks
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Re: How to read cFP-1804 AI channel with modbus I/O server

Hello all,

I'm not quite sure I understand the error you are receiving but I did find this other discussion forum that discusses the fact that addresses are fixed, 5-digit addresses and also references some different modbus functions.

Also, I believe the addresses you are looking for an cFP-AI-100 in slot 1 are 31000 to 31016 for the scaled values (0-30000 psi) and 01000 to 01009 for the pre-scaled values (0.0035-0.024 amps).

Let us know if this isn't what you are looking for.

Happy Holidays!

Janell R | Applications Engineer

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Re: How to read cFP-1804 AI channel with modbus I/O server

All right.  I finally figured it out.

In Wonderware, for an input module in slot 1, I reference 331000 IEEE to 3310014 IEEE in increments of 2 for channels 0 to 8.
Wonderware sees the value as 0.004 to 0.020 amps and is scaled in Wonderware for the range of the transducer.

The raw values are referenced as 3031000 to 3031007.  For a range of 0 to 24 mA, Wonderware sees the value range from 0 to 65536.  This can also be scaled in Wonderware for the range of the transducer.

Hope this helps someone else.

Smiley Happy
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Re: How to read cFP-1804 AI channel with modbus I/O server

Greetings Tommy ,Chrsitens and all:  My english isn't very good, but i will try to explain my problem.  I have a cfp18xx (04 and 08) with a cFP AI 110 (with a signal in the chanel 0 of the slot 2)   and a cFP-DI-330 (with eight signals in its eight chanels)  So i want to connect for modbus/tcp in a system with labview or lookout.  I've installed the modbus help of labview but i dont understand very good the addresses.  I know that cFP18xx can be used like modbus slave and i should give a address to which port.    If some one has an example or some paper more detailed over it, please send me. 
Thanks
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Re: How to read cFP-1804 AI channel with modbus I/O server

Hello Paul,
 
By looking at your email address, I believe you may be better with spanish than english.  Therefore, I have linked the documents in spanish where I can. 
 
Have you looked at the FieldPoint Modbus help files?
 
I also found another discussion forum about Modbus in spanish.  My spanish isn't quite good enough to determine exactly what is going on, but I do know that the last reply points to many other support documents.
 
Good luck!
 
Janell R | applications engineer
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