Level Monitoring | Pressure Sensors
Real-time level monitoring over an IP network using a standard web browser!
Monitor liquid levels with an Pressure Sensor and a ControlByWeb™ module (See recommended products below) Receive text messages or email alerts when a user-specified level is reached. Log and plot the level history, and more.
How do Pressure Sensors Work
Submersible pressure transducers work just like other pressure transducers, except they’re inside a water-tight housing, and they read in feet or inches of liquid (adjusted to specific gravity) rather than PSI.
When a pressure sensor is installed near the bottom of a tank. It uses an internal diaphragm which flexes with changes in pressure. This flexing sends an electrical signal to the attached ControlByWeb module which automatically calculates the depth. This data can then be viewed using a standard web browser over an IP network.
The PT-500 is ideal for clean liquids and can be fitted with a protective cage, making it well suited to handle dirty liquids.
Stainless Steel Enclosure
The PT-500 Series are enclosed in stainless steel, making them compatible with most chemicals.
Easily configure sensor data using the X-404 Modbus Master Controller. No voltage scaling required!
For exisiting systems that require 4-20mA, connect the sensor to one of our compatible devices (X-418, X-420, X-22s).
Tank Vents - Submersible Sensor
Thread the PT-500 Pressure Transducer through vents in a tank.
Tank must be vented to atmosphere.
Connect the pressure transducer to the head pressure to monitor tank levels.
Tank must be vented to atmosphere.
- Max Water Depth: Up to 575 ft. (175.25m)
- Pressure Range: Up to 250 psig
- Accuracy: B.F.S.L. ≤ 0.25% of span
1 year stability ≤ 0.25% of span
- Temp. Compensation Range: 32 to 122°F (o to 50°C)
- Temp. Error (reference temp 70°F):
Zero: ≤ 0.025% F.S./°F | Span: ≤ 0.025% F.S./°F
- RS-485 Modbus | 4-20mA
- Lightning Protection: Built In, Protected against reverse polarity, surge per IEC 61000-4-5
- External Power: 10-28 VDC
- Vented Urethane Cable: Tensile Strength up to 200 lbs
- Lightning Protection: Compliant with IEC 61000-4-5 Standards for electrical surges
- Intrinsically Safe: 4-20mA, Class 1, Div. 1 Groups C & D
- Single Seal
- NO CLOUD NEEDED! Remote connection available with ControlByWeb devices (see below)
- Automatic programming via ControlByWeb device
Sensor Material Options
- 316L SS Sensor | Urethane Cable | Hytrel® Cable | PVC Cable | Delrin™ Nose Cone
- Operating Temp: -40°C to 85°C
- Enclosure Protecton: Submersible to 575 ft.
- Top of tank | Head pressure | Simple to install and program
Users Manual - Modbus (PDF)
Users Manual - 4-20mA (PDF)
Data Sheet (PDF)
Control Pumps Using Pressure Transducer Data
In addition to simple remote monitoring, ControlByWeb modules are fully programmable and provide custom control capabilities as well. For example, you can connect a pump to a relay on a ControlByWeb module and remotely run the pump manually, or configure the pump to automatically run if the level gets too low.
Level Monitoring in Hazardous Environments
Warning: Use of these products to monitor tank levels of potentially explosive liquids or substances (such as gasoline), requires strict adherence to local safety laws and regulations. ControlByWeb modules (such as the X-404, X-420, etc) are NOT designed to be intrinsically safe and must be installed with both physical and electrical safety barriers. Installation should only be performed by qualified individuals and companies who understand the safety requirements. Please refer to sensor installation manuals and consult local safety regulations for more information.
Intrinsically Safe - Modbus Monitoring
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Intrinsically Safe - 4-20mA Monitoring
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Wastewater Lift Station
Ideal for a variety of chemicals, the PT-500 can monitor liquid levels in wastewater lift stations.
Tank level monitoring
Monitor tank levels for tanks with limited access points (i.e., Vents, Head Pressure).
Wastewater Leachate Tanks
Prevent Sanitary Sewer Overflows (SSOs) with the PT-500 and ControlByWeb controllers.
Frequently Asked Questions
Yes. The PT-500 series is made from 316L stainless steel, making it suitable for most caustic or corrosive chemicals.
The PT-500 series includes models that are submersible up to 300 PSI Contact us to get the right sensor and cable length for your needs.
You can adjust the zero in our PT-500 series submersibles with a simple magnet. Simply touch the magnet to the side of the housing, and move it up and down the sensor body to move the zero point up or down as needed.
Electrolysis can occur when the sensor is attached to multiple grounds. A difference in electrical potential between multiple grounds creates a flowing current between them, causing electrolysis.
To fix this problem, you'll need to ensure that your sensor is only attached to a single ground. The electrolysis is probably happening because the submersible sensor is case grounded to the liquid around it, and the current is flowing from the sensor housing to the nearest ground point. All you have to do in this situation is to disconnect the ground wire of the sensor at the wiring terminal inside the control box.
The vent tube on each submersible pressure sensor vents the chamber behind the sensor's diaphram, allowing it to reference the atmospheric pressure when measuring the tank pressure. Blocking or obstructing the vent tube can be detrimental to the sensor, and causes inaccurate readings.
The vent tube must be kept unobstructed as well as dry. Condensation can build up in the vent tube, and drip down into the sensor's electronics. To remedy this, the sensor can be bought with one of the two options: a desiccant cartridge or a hydrophobic, breathable vent cap. Make sure to install one of these to protect the sensors electronics.
Lightning strikes are a big problem for submersibles because they’re often attached to outdoor electronics and submerged below ground. Most distributors recommend buying a separate and expensive surge protector.
With the PT-500 series, lightning protection is built right into the sensor with reverse polarity and surge protection per IEC 61000-4-5.
PT-500 Submersible Pressure Transducer
Compatible ControlByWeb Controllers
X-404 Modbus Master Controller
# of Sensors:
Connect up to 32
- Daisy-Chain modbus sensors
- No voltage scaling
- BASIC Interpreter
- Email Alerts
MND Modbus Display with Aluminum Housing
Local display for up to 10 sensors as a master, slave, or power source on any Modbus network.
Output: 24 V DC±1%, 1.75 Amp
Input Voltage: 100-240V AC
Input Frequency: 45-65 Hz
Power Supply | 12VDC
Regulated, 12V DC, 1.5Amp (100-240V AC Input)