OPERATION
The One Series 2-Wire derives its operating power from the discrete input to which it is connected. Unlike a transmitter, it will do this on a digital channel, not a more expensive analog channel. In most applications this will be the input of a Programmable Logic Controller (PLC), a Distributed Control System (DCS) or an interposing relay. When operating in an “OPEN” condition, One Series 2-Wire draws less than 750 uA of current, which the host device interprets as an open condition. When operating in a “CLOSED” state the switch will pass enough current to be interpreted by the host as a closed condition. Whether its internal switch is open or closed, the One Series 2-Wire obtains a minute but sufficient amount of power to operate continuously - directly from the discrete input. No separate power wiring is required. The PLC/DCS input interprets the One Series 2-Wire connection as if it were mechanical contacts - JUST LIKE A SWITCH!
FEATURES
The One Series 2-Wire has a large, easy-to-read display, showing the process condition and the status of the switch. Set point, deadband and minimum/maximum process values can be easily accessed from the keypad while in operation. One Series 2-Wire also contains patented IAW® self-diagnostic software for assurance that it will switch when needed. With PLUGGED PORT detection enabled, it will watch for process conditions which are evidence of a plugged sensing port, and alert the user to potential problems, locally and remotely. Also, the switch output can be configured for manual reset, requiring the user to manually acknowledge the alarm. Field adjustments can be made to OFFSET and SPAN for calibrating to user instrument and system requirements. Transients and spurious impulses can be filtered using the One Series 2-Wire DELAY feature.
One Series 2-Wire is designed for intrinsic safety, and meets cULus, CENELEC and CE requirements. The NEMA 4X die-cast enclosure is rugged, gasketed and epoxy coated with an all-stainless steel welded sensor
- Powered from PLC/DCS discrete input
- Local LCD display of process and programming values
- All solid state; no moving parts
- No regular calibration required; extended service life
- Field adjustments for offset and span
- Set point and deadband adjustable up to 100% of
range
- Digital accuracy and 0.1% repeatability over wide
temperature range
- 3-year warranty
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ADVANCED FEATURES
• 2-Wire design (Patented)
The One Series 2-Wire innovative design allows the unit to power itself and switch using the same two wires. The electronic switch’s low power requirements allow the One Series 2-Wire to operate using residual current from the PLC discrete input, totally undetected during an open switch condition.
• Easy wiring
The One Series 2-Wire is a direct drop-in replacement for a switch that is attached to a PLC, using the same two wires. No other wiring is necessary. Power and switching signals are accommodated over the same (existing) wire pair. The terminal block wiring is effective for either new construction or field replacement.
• Intrinsically safe (with IS barrier, 24 VDC model only)
The One Series 2-Wire is approved for use in intrinsically safe applications. Galvanically-isolated barrier, part no. 62169-29, is custom-designed for use with the One Series. The One Series is also compatible with standard 28 volt diode barriers supplied from most major manufacturers including MTL 7087+ and Pepperl+Fuchs Z787.
• IAW®(I Am Working) diagnostics
One Series 2-Wire contains the patented IAW® self-diagnostics feature, giving the user peace-of-mind that the instrument is operating properly and will switch when required. Locally, a series of rotating arrows and display messages inform the operator of reliable operation. Remotely, the switch output can be configured to alert the operator to the IAW® status.
• Plugged Port detection (Patent pending Pressure Models only)
One Series 2-Wire IAW® includes an algorithm for detecting a plugged or isolated pressure sensor port, where the medium is viscous or contains particulate matter. When Plugged Port detection is enabled, the One Series 2-Wire display will alert the user locally and remotely, using its IAW® indications.
• Datalogging of minimum and maximum process readings
A very useful feature of the One Series 2-Wire is its ability to record and store the minimum and maximum process “extremes” in non-volatile memory. The values remain in memory until they are manually reset, using a key sequence on the keypad.
• Latching or automatic reset
The switch output can be field-configured for either automatic reset or latching. The latching feature provides a “manual reset” requirement, making it necessary for the operator to intervene and determine why the alarm occurred.
• Delay (nuisance trip) filtering
The One Series 2-Wire is designed to react quickly to very small process variations. Certain short-duration events (pressure spikes) can cause nuisance trips and shut down a process unnecessarily. Delay (event) filtering can be enabled by choosing the maximum time duration (1/4, 1/2, 1 or 2 seconds) within which the One Series 2-Wire will ignore (filter out) the process variation. With this feature disabled, the One Series 2-Wire reacts within 50 mS to all process variations.
• Certified to Enclosure Type 4X/IP66
Corrosion resistant enclosure is epoxy-coated aluminum with a gasketed, Lexan® faceplate to withstand harsh and dirty environments and plant wash-downs.
• Agency Certifications: cULus, CENELEC, and CE approvals
The One Series 2-Wire has been rigorously tested by independent agencies to ensure adherence to required industrial specifications, manufacturing practices and quality. Each One Series 2-Wire is backed by a limited 3-year warranty.
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