0 should bring in the raw counts. Feed the output of that block to the MEAS parameter of another AIN block and set the SCI there. Regards, Alex Johnson Invensys Process Systems Invensys Systems, Inc. 10707 Haddington Houston, TX 77043 713.722.2859 (voice) 713.722.2700 (switchboard) 713.932.0222 (fax) ajohnson@xxxxxxxxxxx -----Original Message----- From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx] On Behalf Of Ken.E.Moore@xxxxxxxxxxx Sent: Wednesday, February 09, 2005 12:54 PM To: foxboro@xxxxxxxxxxxxx Subject: Re: [foxboro] Analog values from Triconex to I/A via Modbus Int 30 I know this isn't it, but I gotta ask, have you tried SCI of 0 (zero) I don't have any experience with Triconex, but I use a Mod Int 30 to communicate with an older TI plc, and I bring in data registers with the AIN block, and a SCI of zero. Works great. Ken "Gregory A Hurwitt" <hurwitg@xxxxxxxxxxxxx>@freelists.org on 02/09/2005 12:32:24 PM Please respond to foxboro@xxxxxxxxxxxxx Sent by: foxboro-bounce@xxxxxxxxxxxxx To: foxboro@xxxxxxxxxxxxx cc: (bcc: Ken E Moore/US/NSC/ICI) Subject: [foxboro] Analog values from Triconex to I/A via Modbus Int 30 Hello list, I am trying to communicate a few analog values from a Triconex system (Tricon V9.x) to I/A (V6.x) via a Modbus Integrator 30. These values are calculated in the Triconex, and stored in read-aliased real memory locations. (Alias numbers beginning at 33001.) My MDSCAN block is set up with DATYPE = 4 (read-only analog data beginning at address 30000). I am aware that only the integer portion of my value will be communicated, and this is perfectly acceptable for my application. The problem I am having is that a value of 0.0 at the Triconex is interpreted as 819 raw counts in my Mod Int 30 AIN block. This happens regardless of the setting for SCI in the AIN block. (Makes sense; signal conditioning is applied *to* raw counts to generate the measurement value.) A value of 32767.0 at Triconex is seen as 32767 counts at the AIN block. The "offset" in the raw counts is linear between these two endpoints, so I have been able to come up with KSCALE/BSCALE factors that allow me to work around the problem. IMO, this is a very ugly workaround. Of course, anyone who has worked with Triconex at all knows that 0-20 mA analog inputs are interpreted in the system as 0-4095 counts, and that 819 counts is the exact value for 4 mA. It seems like I/A is trying to "help" me by accounting for a 4mA zero signal, although it does seem backwards (819 in Triconex should be interpreted as 0 in I/A, not vice versa as is happening). However, none of this applies to my situation, since I'm not looking at an analog input in counts in Triconex, but rather a calculated value already in engineering units. I simply want to communicate the existing value with no modification. Is there an SCI setting that "reverses" the 819 count offset? I sure don't see one in the documentation. Or do I have something configured incorrectly? Or is this a known limitation of the Modbus Integrator 30? Thanks, Greg Hurwitt BASF Freeport _______________________________________________________________________ This mailing list is neither sponsored nor endorsed by Invensys Process Systems (formerly The Foxboro Company). Use the info you obtain here at your own risks. Read http://www.thecassandraproject.org/disclaimer.html foxboro mailing list: //www.freelists.org/list/foxboro to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave __ This email has been scanned for Viruses and Spam. For more information please contact your local Information Security representative. ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ _______________________________________________________________________ This mailing list is neither sponsored nor endorsed by Invensys Process Systems (formerly The Foxboro Company). Use the info you obtain here at your own risks. Read http://www.thecassandraproject.org/disclaimer.html foxboro mailing list: //www.freelists.org/list/foxboro to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave _______________________________________________________________________ This mailing list is neither sponsored nor endorsed by Invensys Process Systems (formerly The Foxboro Company). Use the info you obtain here at your own risks. Read http://www.thecassandraproject.org/disclaimer.html foxboro mailing list: //www.freelists.org/list/foxboro to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave