"The real difficulty is that 10% to 20% of a project's cost can come from late wiring changes, and this can delay a project by one or two months at the end." Supervised by Chief Strategic Officer Peter Zornio, Emerson's Duncan Schleiss, vice president, platform strategy, demonstrates how single-channel Charms make it easy to accommodate late changes in project specifications.The real difficulty is 10% to 20% of a project's cost can come from late wiring changes, and this can delay a project by one or two months at the end, said Dicaire. "Also, the typical I/O card has eight or 16 channels that are grouped together for the same type of signal, but the field wiring on the marshalling strip has a mix of analog and digital signals, and so it can be very hard to get the right signals to the right cards," he added. "As a result, the risk is overloaded or under-loaded controllers, so users always have to buy extra to make sure they have enough. The also have to cope with late changes from their customers, such as changing wiring from altered tanks or limit switches to transmitters, or finding they need to make other changes when they test the controllers."
Unfortunately, the risk of over- or under-loaded controllers meant that users didn't just have to buy too many controllers, but they also had to find added space for them and their associated I/O devices.
"Users can just land their multi-core cables in order, each signal tells what it is, and so the users can simply insert a Charm I/O card for that signal type, whether it's analog, digital, input or output," said Dicaire. "It doesn't matter what a device is because there's an appropriate Charms module that can take its signal, convert it and put in on the bus. For example, if a user already has a mix of signals, but wants to add their first RTD, then they can just wire it in, plug in the right Charm module, and they're done."
In general, Charms I/O cards mean users don't have to rewire their I/O nearly as much, don't have to buy as many I/O cards, and don't need to manually reassign I/O to different controllers. "Now, it can be just a quick point and click. Users can reassign up to 50 signals in a matter of seconds. This used to be a three- or four-day job," said Dicaire.
Another key feature of Charms I/O cards is they also have a HART channel and model that comply with the new HART 7 protocol. "This means users can pull and update their HART data in about 0.5 seconds, instead of the 5-6 seconds that it used to require," added Dicaire.
Charms I/O cards also comply with DeltaV Version 11 and will comply with its future versions. "Charms I/O cards change the game because of the huge amounts time they can save for users," said Dicaire. "For example, some users could cut their wiring time in half. The need for many wiring changes, especially late wiring changes, will effectively go away. This could enable some users to commission their applications one or two months earlier.