New RTD signal conditioners with USB configuration

The initial offering in Acromag’s new ST130 series of low-cost, temperature transmitters is an ASIC-driven RTD signal conditioner, Model ST131. Units combine the simplicity of a digital USB setup and calibration interface with the inherent performance advantages of analog signal conditioning. Selling for just $89 with free Windows configuration software, this DIN Form B head-mount instrument will convert the input signal from any 100 ohm Platinum RTD sensor to a highly accurate, loop-powered 4-20mA output. A ruggedized design features -40 to 80°C operation, electrical noise immunity, and surge protection. CE and UL/cUL Class 1 Division 2 Zone 2 approvals are pending.

“Our new ST131 RTD transmitter employs the best of analog and digital technologies at a very attractive price,” states Don Lupo, Acromag’s sales and marketing director. By maintaining a fully analog signal path (i.e. no digitization), the transmitter delivers optimal accuracy, noise resistance and response speed. Additionally, the unit supports digital calibration to eliminate zero/span pots, DIP switches, and pushbuttons for easy programming of ranges, over/under scale thresholds, and fail-safe settings.

Despite their tiny size and economical price tag, ST131 transmitters are full-featured. These transmitters provide sensor excitation and perform advanced signal linearization, lead-wire compensation, and sensor fault detection functions. Units can also support any 100 ohm Pt RTD sensor (alpha = 375-393) or 0-900 ohm input. Designed for harsh environments, the unit’s ASIC exhibits very low drift across wide ambient temperatures and is highly resistant to RFI, EMI, ESD, and EFT effects. Simultaneous differential sampling and auto-zero techniques yield further accuracy improvements. Another benefit, the output is non-polarized and reverse polarity protected. Factory calibration is also available.

A variety of options add greater flexibility. Programmable over/under range and fault/alarm levels enable identification of a “runaway” process or broken sensor. Selectable up/downscale failsafe modes ensure a safe, predictable shutdown with a NAMUR-compliant fault response.

For easy installation, Acromag sells a variety of mounting and wiring accessories. A USB-to-USB isolator protects equipment from ground loops, electrical noise, and surges during configuration. For convenience, a kit supplies the software, isolator, and USB interface cables. Numerous connection head enclosures are also available through Acromag. Select from stainless steel, aluminum, and cast iron housings with explosion-proof or general-purpose ratings. A DIN rail adapter adds more mounting options.

Acromag is an international corporation that has been developing and manufacturing measurement and control products for more than 50 years. They offer a complete line of industrial I/O products including process instruments, signal conditioning equipment, data acquisition boards, distributed I/O modules, and network communication devices.