The Spirax Sarco PA420 boiler level capacitive probe 4-20mA preamplifier uses a 300 series austenitic stainless steel body and provides a two-wire 4-20 mA loop current output proportional to the level. The device is compatible with operating conditions with a minimum water conductivity of 5 μS/cm, supports EN175301-803 electrical connection, and has a shielded cable transmission distance of up to 100 meters. It is specifically designed to work with Spirax Sarco capacitive probes, amplifying and converting capacitance signals to achieve precise transmission and processing of boiler level signals to remote control systems.
PA420 product photo
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Spirax Sarco PA420 Boiler Level Capacitive Probe 4-20mA Preamplifier
Capacitive probe preamplifier, converts boiler level signals into two-wire 4-20mA output.
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Specifications
- Supply voltage
- 9 - 26.4 Vdc
- Loop current
- 4 - 20 mA
- Output signal
- 4-20 mA proportional to level
- Maximum load resistance
- 500 Ω
- Linearity
- 2% FSD
- Insulation voltage
- 100 Vdc (capacitive)
- Applicable sensor length
- 370 - 1500 mm
- Ambient temperature range
- 0 - 70 °C
- Pollution degree
- 3
- Minimum water conductivity
- 5 μS/cm or 5 ppm
- Maximum cable length
- 100 m (shielded)
- Electrical connection standard
- EN175301-803 (DIN 43650) / ISO4400
- Cable gland specification
- Pg11
- Body material
- 300 series austenitic stainless steel
- Seal material
- Silicone rubber, nitrile rubber
- Electromagnetic compatibility directive
- 2004/08/EG
Application scenarios
Remote transmission of level signals to control systems
The PA420, used with Spirax Sarco capacitive probes, amplifies the measured capacitance signal and converts it into a two-wire 4-20 mA signal proportional to the level, for remote monitoring or processing by Spirax Sarco controllers or converters with current input. When using shielded cable, the maximum cable length is 100 m.
FAQ
What is the function of the PA420 preamplifier?
The PA420 is used with Spirax Sarco capacitive probes to amplify the measured capacitance signal and convert it into a 4-20mA output proportional to the level, and can be used with Spirax Sarco current input controllers or converters.
What lengths of sensors is the PA420 compatible with?
The PA420 is suitable for various compatible sensors with lengths of 370-1500mm. The specific configuration must be confirmed according to the actual model and application conditions.
What are the power supply and output parameters of the PA420?
The PA420 uses two-wire 4-20mA loop power supply, with an operating voltage of 9-26.4Vdc, loop current of 4-20mA, maximum cable length of 100m, and requires the use of shielded cable.
What should be noted during installation of the PA420?
The PA420 should be screwed onto the capacitive sensor and hand-tightened. Both the preamplifier and the compatible sensor may be equipped with an O-ring; only one of them needs to be used for sealing.
Can the PA420 be installed outdoors?
Without additional environmental protection or rainproof facilities, the PA420 is not suitable for outdoor installation. The ambient temperature should be controlled within the range of 0-70 °C.