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Modpoll's communication setup seems to support only a single IP address for the server. So I've been unable to view two Modbus/TCP servers, each in the their own window because I cannot find a means to establish a 2nd communications setup for a 2nd server. I know at some time in the past, I...

I went to find the download link to reply to someone inquiring about Modbus RTU CRC and was quite surprised that Modbus.org has removed its published specifications/standards from their formerly open, freely accessed web page. I thought maybe it was just a simple registration to get access, but...

Report from the field: A flow meter with a Modbus RTU RS-485 port runs OK when polled by a Windows box with a USB/485 converter. But when the Modbus master is replaced with either 1 of 2 PLCs, the Modbus comms runs only 3-5 minutes, before it fails. While running, comms passes valid data...

Softing provides industrial protocol analyzers, gateways and OPC software so Softing is well versed in the intricacies of OPC DA. Microsoft's DCOM is an integral part of OPC DA, a widely used data transfer protocol in the automation and control markets. Attached is Softing's notice of the...

Does any old-timer out there have a pile of ISA Journals or InTech magazines taking up space that I could scan and OCR in order to preserve some of the history of process instrumentation and control? I'm about to hang up my hat and retire and will have time to digitize the 'lost' (paper)...

I have pdf'd dozens of threads over the years for reference. After the format change, a resulting pdf file lists latest threads but contains no thread content, no posts, so it is basically a near empty pdf file. Any fix for thread pdf's? Sample pdf attached

ISA's Modbus CAP question fails with a grade of F The ISA (formerly Instrument Society of America, more recently the International Society of Automation) web site has a sample CAP (Certified Automation Professional) program study guide question that happens to be about Modbus. It's an awful...

What kind of Modbus does ABB's Totalflow flow meter have? The explanation of the register maps is, "Totalflow G4 devices provide access to application data by numeric tags. These numeric tags consist of three values – application number, array number and register number. These three...

To the moderators, Control.com already has feedback for individual posts in the form of "Is the post helpful". I'd like to propose a 2nd feedback (green star instead of a blue star?): Did this post make you laugh? When Mr. Ingraham replied, "To the extent, we don't "need" relays any...