KOBOLD SEN Pressure Transmitter
The KOBOLD SEN is a compact pressure transmitter built around a piezoresistive ceramic sensing element for economical gauge pressure measurement. Rated to a 0.5 accuracy class (±0.5% of full scale), it covers spans from full vacuum at -30 inHg through 0 to 10000 PSIG (0 to 689.5 bar) and delivers a 4-20 mA or 0-10 VDC output signal.
Ceramic Sensing Element and Operating Principle
At the core of the SEN is a thick-film piezoresistive ceramic (Al2O3) element working with an internal diaphragm. Applied pressure deflects the element, which produces a proportional electrical signal. The ceramic construction is designed to deliver long cycle life with minimal calibration drift, and it responds in 1 ms or less within 10 to 90 percent of full scale.
Under reference conditions, long-term stability is rated at ±0.2% of full scale per year. The design suits systems with high, fast pressure peaks, such as hydraulics.
Measuring Ranges and Accuracy
The SEN is offered in more than twenty gauge pressure spans, from a -30 to 0 inHg vacuum range through 0 to 10000 PSIG, each chosen by an order code. The accuracy class is 0.5, characteristic deviation is within ±0.3% of full scale, and repeatability is within ±0.15% of full scale.
Overpressure capability depends on the range: units rated below 870 PSIG (60 bar) withstand twice their range, and units above 870 PSIG withstand 1.5 times their range.
Output Signals and Electrical Connection
Two output versions are available: a 4-20 mA two-wire signal or a 0-10 VDC signal. Auxiliary power is 15 to 32 VDC, and for the current output the permissible load is the supply voltage in volts minus 15, divided by 0.02 A. The sensor connects through a DIN 43650 A plug, an M12x1 plug, or a cable.
Connector poles are marked UB+ (supply positive), 0V (supply negative), S+ (signal positive), and S- (signal negative). Wiring must follow the sketch on the type plate, since incorrect wiring can damage the unit’s electronics.
Materials, Temperature, and Protection
The wetted parts are a 304 stainless steel process connection, the ceramic (Al2O3) sensing element, and an NBR O-ring (other O-ring materials on request); the housing is 303 stainless steel. The enclosure carries an IP 65 rating.
Media temperature ranges from -4 to 250°F (-20 to 121°C). Ambient and storage temperatures range from -22 to 212°F (-30 to 100°C), and the compensated range is -13 to 185°F (-25 to 85°C). Temperature drift is within ±0.02% of full scale per Kelvin at zero and ±0.01% per Kelvin on span.
Process Connections and Installation
The SEN uses a 1/4" NPT connection (model SEN-8700) or a 1/2" NPT connection (model SEN-8600). Mount the transmitter away from vibration and radiated heat, and seal the threaded port with DIN 16258 sealing discs or profile washers. After the mechanical and electrical connection is made, the sensor operates immediately.
Standard units are not intended for hazardous areas or oxygen service. The sensors are maintenance-free and contain no field-serviceable parts, so any repair is carried out at the factory.
Applications
The SEN is designed for OEM use in medium to high quantities and for measurement in chemically aggressive media and under mechanical load. Typical applications include:
- Plant engineering
- Environmental engineering
- Machine building
- Cooling circuits
- Hydraulic systems with high, fast pressure peaks
Ordering and Display Options
A model number combines the process connection, the output digit, and the range code. For example, SEN-8600N4 0 P025 specifies a 1/2" NPT connection, a 4-20 mA two-wire output (digit 0; digit 2 selects 0-10 V), and a 0 to 15 PSIG range. Range codes run from H315 (-30 to 0 inHg) through P165 (0 to 10000 PSIG).
An AUF plug-on display can be added: the AUF-1000 standard display and the AUF-1001 display with open collector, both for 4-20 mA two-wire operation.
Common Questions about SEN - Pressure Transmitter
The SEN comes in over twenty pressure ranges, spanning a -30 inHg vacuum point up to 0-10000 PSIG (0 to 689.5 bar). It reads gauge pressure. Overpressure capability is twice the range below 870 PSIG (60 bar) and 1.5 times the range above that value.
The SEN corresponds to accuracy class 0.5, equal to ±0.5% of full scale. Characteristic deviation reaches ±0.3% at most, repeatability ±0.15%, and long-term drift ±0.2% per year, each figure expressed against the measuring span.
The SEN offers two output choices: 4-20 mA on a two-wire loop, or 0-10 VDC. Supply voltage runs from 15 to 32 VDC. On the current version, allowable load is the supply minus 15 V divided by 0.02 A, and response time is 1 ms or less.
In contact with the medium are a 304 stainless steel connection, the ceramic (Al2O3) element, and an NBR seal, with other seal materials on request; the 303 stainless steel housing is non-wetted. The construction resists aggressive media and mechanical load, though standard units are not for oxygen service.
Two thread options are offered: 1/4" NPT (model SEN-8700) and 1/2" NPT (model SEN-8600). Choose a mounting point free of vibration and nearby heat, then fit DIN 16258 discs or profile washers on the threaded port. Keep within the rated data, and the sensor works once wired.
The SEN operates with media between -4 and 250°F (-20 and 121°C). Its ambient and storage window is -22 to 212°F (-30 to 100°C), while the compensated span sits at -13 to 185°F (-25 to 85°C). Drift per Kelvin is held to ±0.02% at zero and ±0.01% on span.
A SEN part number joins the connection, an output digit, and a range code. In SEN-8600N4 0 P025, the 8600 denotes 1/2" NPT, the 0 selects 4-20 mA two-wire output (a 2 would select 0-10 V), and P025 sets a 0-15 PSIG span. Range codes span H315 through P165.
Yes. The AUF plug-on display mounts directly on the transmitter. The AUF-1000 is the standard version, and the AUF-1001 adds an open collector output. Both run on a 4-20 mA two-wire loop. See the AUF product datasheet for full technical details.
The SEN is maintenance-free and has no parts that can be repaired or exchanged in the field, so any repair is handled at the factory. The ceramic sensing element is designed for minimal calibration drift across its service life, and the housing is rated to IP 65.
Product Specifications
Measuring Ranges
-30"...0" Hg Vacuum to 0...10000 PSIG
Analog Output
4-20 mA or 0-10 VDC
Wetted Materials
304 SS, Ceramic, NBR
Product Features
Sensing Ranges from -30” Hg to 10000 PSIG
Ceramic Pressure Sensing System for High Cycle Life
Sample Applications: Plant Engineering, Environmental Engineering, Machine Building, and Cooling Circuits
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