Archive for category siemens
The HART communication protocol has been firmly established as the standard means of configuring field instruments for some years. But talking to a field instrument needs a communicator.
There are the handheld communicators, Rosemount’s x75s and the “budget-priced” Meriam MFC 4150, but at a cost that’s more a capital appropriation than an MRO expense. Even the Meriam, with a 3-year field device description subscription starts at more than $4000.
People continue to ask me if there isn’t a more budget conscious approach to HART configuration.
When you’re making programming changes to a field device, you don’t always have time to wait. Here’s a hidden feature that helps you speed up the process between Siemens SIMATIC PDM and HART field instruments.
Normally, when you’re using PDM software, it takes a minute or so to upload or download changes to and from your HART devices. Seems like an eternity when all you need to do is change a range.
So, I’m going to let you in on a feature you might not have seen before.
RTDs are great temperature sensors – accurate and easy to install. But they are not friendly when it comes to trying to get a single RTD to go to two places, like when an RTD temperature measurement has to go to both a controller and a recorder. People call and ask, “How do I split an RTD signal?” The short answer is, “You can’t.”
An RTD cannot be wired in parallel or in series to a second device. Any RTD input supplies a known, regulated ‘excitation’ current to the RTD. Mixing RTD inputs would mix currents and that’s a Big No-No.
There’s also a lead wire compensation circuit for 3- or 4-wire RTDs that would create problems if a single RTD were connected to two different RTD inputs. There’s just no feasible means of making two RTD analog inputs play nice together.
But all is not lost. There are several ways to achieve your goal.
Part of my job as the technical specialist at Lesman is to make sense of new products and upgrades, and figure out what’s really going to matter most to our customers.
Sometimes it’s just a matter of a much-needed new functionality, or better configuration tools, easier mounting, or switching to the most current form of data storage.
In the case of Siemens’ latest ultrasonic controller, it’s all that and more.
Siemens (and Milltronics) ultrasonic controllers and transceivers, like the HydroRanger, MultiRanger, and OCM-III have been around for years with no significant improvements. Instead of updating these devices, Siemens has done a complete redesign, and introduces the SITRANS LUT400 as the first device in the new ultrasonic controller family.
Here are my initial thoughts on this new player in the ultrasonic game.