Re: [foxboro] Word-Swaping on Modbus Interface Micro I/A

I recall a similar situation with regards to swapped order on bits through
the FMCIN and FMCOUT blocks.
This happened in 1999 so please excuse me if it seems a bit fuzzy...
My subconscious reminds me that I had solved the inversion issue by setting
the MULTWR parameter of the ECB109 to 0...(I had previously set it to 1)
Unfortunately, I do not recall the exact implication of this change other
than that it actually solved it for me.
This of course is much less defined and documented as Steve's solution.

Howard
-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx] On
Behalf Of steve.shimp@xxxxxxxxxxxxxx
Sent: Tuesday, February 14, 2006 8:21 AM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] Word-Swaping on Modbus Interface Micro I/A

Rolf,

We have done this with RIN blocks on a Modbus interface.  The "trick" is to
use 2 separate RIN blocks for each 16-bit word.  Then use a CALC block to
manipulate the two values from the RIN blocks to determine the original
value.

For example, there is a value transmitted over the Modbus interface that is
67098.2 originally.  The words are transmitted such that the first word is
the low order bits and the second word is the high order bits.  The first
word is pulled into a RIN block that has an MGAIN value of 0 (zero).  The
second word is pulled into a RIN block that has a MGAIN value of 1000
(based upon the documentation of the Modbus sending device and how the
interface is designed).  The RIN blocks are therefore "reading" 98.2 for
the low order and 67000 for the high order.  Pull these RIN blocks into a
CALC block and simply add them together.

Hope this helps.


Steve Shimp
Maintenance & Systems Engineer
ExxonMobil Paulsboro Lube Plant
phone: 856.224.5059      cell: 609.820.8501      fax: 856.224.5030
email:  steve.shimp@xxxxxxxxxxxxxx

foxboro-bounce@xxxxxxxxxxxxx wrote on 02/14/2006 08:00:55 AM:

>
> Hi List,
>
> our I/A-System is Unix V6.4 and Micro I/A V6.2.5 with 2 Modbus serial
> Interfaces attached. I would like to read/write data from/to a Modbus
> Device (Brabender weighing unit) with FRIN /FROUT blocks. But the two
16bit
> Modbus Words for a real value are in wrong order.  Example: Value 12.34
in
> the Modbus Adresses 47200 and 47201 (Value Hex 70A4 4145) will be
displayed
> on FoxView as 4017238209...................... How can I change the Order
> of the Modbus Adresses to 47201 and 407200 (Value Hex 4145 70A4) on the
> I/A-System? There is no way to change it on the Modbus Device!
>
> Thanks for helping,
>
> Regards
>
> Rolf Reber
> ____________________________________
> EMS-CHEMIE AG
> Business Unit EMS-SERVICES
> Abt. Anlagenbau / Prozessleitsysteme
> Reichenauerstrasse
> CH-7013 Domat/Ems
>
> Phone: +41 (0) 81 / 632 71 49
> Fax:      +41 (0) 81 / 632 74 04
> mailto: rolf.reber@xxxxxxxxxxxxxx
> http://www.emsservices.ch

 
 
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