Otek introduces the programable logic controller and transmitter (PLCT), an independent panel with digital meter, controller and current loop transmitter. Otek manufactures measurement and control devices with more than 50 years in operation. Otek President Dr. Otto Fest notes that industry used to largely rely on analog meters, but many are now moving to digital. Otek is a small company by design, Fest says, and it has specialized in upgrading old analog meters with digital.
The transmitter can ultimately convert more than 50 types of input signals in the instrument and control (I&C) room to 4-20 mA current loop, which Otek calls the “One for All,” one transmitter for all inputs. It displays both the input, as a percentage of full scale, and the output. This can eliminate the need for duplicate meters in parts inventory, and different meters in multiple locations can all be integrated together. The full system combines other Otek meter technologies: the universal panel meter (UPM) series, new technology meter (NTM) signal and external power series and plug-and-play (PNP) digital meter series.
“I was trained that we cannot afford to take a chance, so it has to be ultra-reliable with the fewest number of components,” Fest says.
The lack of reliance on power can make an analog device more reliable than digital signals, which are susceptible to interference or dropped signal due to power issues. Additionally, very few manufacturers make analog meters anymore, Fest says, so industry often must rebuild them where they are still in use or work toward converting to digital. Otek’s new PLCT needs only 4-20 mA signal to measure it and to power the instrument. “In other words, it’s almost like an analog meter. An analog meter doesn’t require power. All it requires is a signal.”
Otek digital meters use ultra-bright white LED digits or automatic programmable tricolor LEDs. The system is designed with a colored scale plate, which can be any color, text, scale language or meter identification codes. The universal scale plate can be attached to the front of the filter on the outside of any meter.
The PNP series is 100% NEI08-09 compliant, 4.5 digits (for example, 1014.2) and powerless (loop or external power) with USB isolated output only. The NTM LED display has 3.5 digits, loop or external power, patented graphical user interface (GUI) and Class 1E and Military Standard approved. The UPM display accepts analog and digital signals, loop or external power.
The PLCT has dual display meters, which plug into a 1-inch square module to convert it from a meter to transmitter. “Again, in an emergency or at high seas or under it, you can convert any meter to transmitter or vice versa and any meter for any original signal regardless of input range,” Fest says.
The PLCT displays any input signal value on the top display, with a the 4-20 mA output signal on its bottom display. It can automatically control the process via ON/OFF with a number of relays options, such as single pole double throw (SPDT) relays up to 10 Amps, metal oxide semiconductor field effect transistor (MOSFET) alarms, octal and reed relays and also Otek’s adjustable and programmable proportional integral derivative (PID) controller. The fail-safe control is powered entirely by the current loop with a range of up to 2 miles. It fits standard 1/8 DIN panels or can be DIN-rail or custom-mounted.
It is also 100% compatible with Ethernet, RS-485 and USB serial I/O. Its 4-20 mA output enables automatic control through supervisory control and data acquisition (SCADA), distributed control system (DCS), programmable logic controller (PLC) or directly. Operators can manage it locally or remotely via PID.
The PLCT can be combined with Otek’s cabinet and panel options, the digital I&C cabinet (DICC) and desktop I&C (DTIC). Commercial-grade prototypes have demonstrated full digital replacement of up to 500 analog meters, independent and operator-controlled, via 4-20 mA signal conversion. Otek says system integrators can then route all inputs and outputs through the DICC or DTIC.
“Our main goal is reliability,“ Fest says. “We don’t use any electrolytic capacitors because they have a tendency of failing 10-20 years later.”
Feedback from the Electric Power Research Institute (EPRI) and Idaho National Laboratory (INL) helped shape the development of the PLCT, Fest says. They performed independent evaluations of Otek’s direct digital replacements for analog meters, as part of Modernization Technology Assessment (MTA) 3002020578. EPRI’s plant modernization toolbox (PMTB) is a resource to facilitate decision-making and executing modernization projects at nuclear power plants. Many of Otek’s customers are military, largely U.S. Navy and U.S. Coast Guard, nuclear and water utilities, and power plants, including coal, gas and hydro facilities.
For more information, visit www.otekcorp.com.
