FP201A-L31

The Yokogawa FP201A-L31 is a compact pressure transmitter in the FP Series High Accurate Pressure Sensor range. The FP201A measures absolute pressure and converts the measured pressure into a proportional 4-20 mA DC output for connection to an industrial control or monitoring system. Its exact measuring range and process connection should be verified against the complete model code and product nameplate before replacement.

Pressure Measurement and Output

The FP201A uses an absolute-pressure reference, measuring pressure relative to absolute vacuum rather than local atmospheric pressure. Its 4-20 mA DC output is proportional to the configured pressure span, allowing the receiving instrument to convert the current signal into a pressure reading.

The transmitter uses a two-wire circuit, with the supply power and measurement signal sharing the same current loop. This arrangement supports direct connection to compatible analog current-input channels.

Model Configuration

The available model-code information identifies the following configuration:

• L: 0 to 100 kPa absolute pressure measuring range.
• 31: R1/4 tapered pipe thread process connection.

The L range is designed for absolute-pressure measurement. Its maximum allowable pressure is 400 kPa, which must be considered when checking the operating pressure and possible pressure surges.

Technical Specifications

Parameter	Specification
Model	FP201A-L31
Brand	Yokogawa
Product Type	Absolute Pressure Transmitter
Series	FP Series
Measuring Range	0 to 100 kPa abs
Pressure Reference	Absolute
Output Signal	4-20 mA DC
Output Configuration	2-wire
Process Connection	R1/4 (PT1/4)
Measurement Accuracy	+/-0.25% of span
Maximum Allowable Pressure	400 kPa
Supply Voltage	12 to 28 V DC
Recommended Supply	24 V DC +/-10%
Load Resistance	0 to 600 ohm at 24 V DC
Time Constant	3 ms or less
Operating Temperature	-40 to 80 deg C
Compensation Temperature	0 to 60 deg C
Measured Fluid	Liquid or gas
Enclosure Classification	IP66 water-resistant type
Diaphragm Material	Hastelloy-C
Nipple Connector Material	SUS316
Fill Fluid	Silicone oil
Case Material	Aluminum alloy
O-ring Material	Fluoro rubber (Viton)
Weight	230 g
EMC Standard	EN 61326-1 Class A, Table 2; EN 61326-2-3

Electrical Connection and Signal Interpretation

The FP201A operates with a 4-20 mA two-wire output. At the configured zero and full-scale pressure points, the output corresponds to 4 mA and 20 mA respectively. Intermediate pressure values produce proportional current signals.

For the FP201A cable connection, the red wire is positive and the black wire is negative. The white and green wires are not used for the current signal connection. The receiver input resistance must be considered together with the supply voltage to keep the loop within its specified operating limits.

Frequently Asked Questions

Q: What is the difference between FP201A and FP201?

A: FP201A measures absolute pressure, using absolute vacuum as its reference. FP201 measures gauge pressure, using local atmospheric pressure as its reference. Both models provide a 4-20 mA DC output.

Q: What pressure range does the FP201A-L31 measure?

A: The L range identifies 0 to 100 kPa absolute pressure. Its maximum allowable pressure is 400 kPa. The pressure range and process connection should be checked against the product nameplate before installation.

Q: Is the FP201A-L31 suitable for hazardous gas environments?

A: No. The FP201A is not designed as an explosion-proof instrument. Yokogawa specifically warns against using this sensor in environments containing explosive gas.

Product Lifecycle Information

Yokogawa lists the FP Series compact pressure sensors as discontinued products. The manufacturer's discontinuation notice identifies the FP Series as a legacy product family and provides EJA530J as a recommended Yokogawa alternative. The EJA530J should not be treated as a direct drop-in replacement without checking the measuring range, process connection, output and installation requirements.

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