The SMC Digital Flow Switch (Integrated display type), model PF3W7##, is a device designed for measuring and controlling fluid flow in industrial applications. It features an integrated display for real-time flow monitoring, settings, and error codes.
Function Description
The primary function of the PF3W7## is to detect and display fluid flow, offering switch functions based on set flow values. It utilizes the Karman vortex principle to measure fluid flow rate, where the frequency of vortices generated by an object in the fluid stream is proportional to the fluid velocity.
The device offers various output modes for OUT1 and OUT2:
- Hysteresis mode: The switch turns ON when the flow exceeds a set value and OFF when it falls below the set value minus a hysteresis value, preventing chattering from pulsation.
- Window comparator mode: The switch output turns ON or OFF depending on whether the flow is inside or outside a range defined by two set values (P1L/n1L and P1H/n1H).
- Accumulated output mode: Generates a pulse every time a predefined accumulated flow passes, allowing for total accumulated flow calculation. This mode can be set for incrementing or decrementing accumulated flow.
- Temperature sensor output (OUT2 only): When equipped with a temperature sensor, OUT2 can be configured to output fluid temperature in either hysteresis or window comparator mode.
The device also supports an analogue output, providing a value proportional to the flow rate (1 to 5 V or 4 to 20 mA) or fluid temperature (1 to 5 V or 4 to 20 mA).
External input functionality allows for remote resetting of accumulated flow, peak values, and bottom values.
Important Technical Specifications
General Specifications (Metal attachment):
- Applicable Fluid: Water and ethylene glycol solution with a viscosity of 3mPa·s (3 cP) or less.
- Detection Method: Karman vortex.
- Rated Flow Range: Varies by model: 0.5 to 4 L/min (PF3W704) up to 50 to 250 L/min (PF3W721).
- Display Flow Range: Corresponds to rated flow range, with lower limits displaying 0.00 or 0.0.
- Switch Point Range: Corresponds to rated flow range.
- Min. Setting Unit: 0.01 L/min to 2 L/min, depending on the model.
- Conversion of Accumulated Pulse (Pulse width = 50 ms): 0.05 L/pulse to 2 L/pulse, depending on the model.
- Fluid Temperature: 0 to 90 °C (No freezing and condensation) for metal attachment, 0 to 70 °C for vinyl chloride piping.
- Display Unit: L/min for real-time flow and L for accumulated flow.
- Accuracy: ±3%F.S. max. (Display and analogue output).
- Repeatability: ±2%F.S. max (±3%F.S. when response time is 0.5 s).
- Temperature Characteristics: ±5%F.S. max. (25 °C reference).
- Operating Pressure Range & Proof Pressure: Refer to graphs for specific values based on fluid temperature.
- Accumulated Flow Range: 99999999.9 L.
- Switch Output: NPN or PNP open collector output, 80 mA max. load current, 28 VDC max. applied voltage. Internal voltage drop: NPN: 1 V max., PNP: 1.5 V max. (at 80 mA load current).
- Response Time: 0.5 s/1 s/2 s (7 s for temperature sensor output).
- Output Protection: Short circuit protection.
- External Input: Voltage free input of 0.4 V or less (reed or solid state type) for 30 ms or longer.
- Display Method: 2-screen display (Main screen: 4-digit, 7-segment, 2-colour; Sub screen: 6-digit, 11-segment, White). Display updating frequency 5 times/sec.
- Indicator Light: Output 1 and 2: Orange.
- Power Supply Voltage: 12 to 24 VDC ±10%.
- Current Consumption: 50 mA max.
- Enclosure: IP65.
- Operating Temperature Range: 0 to 50 °C (No freezing and condensation).
- Operating Humidity Range: Operation, Storage: 35 to 85%R.H. (No condensation).
- Withstand Voltage: 1000 VAC, for 1 minute between terminals and housing.
- Insulation Resistance: 50 MΩ min. (with 500 VDC) between terminals and housing.
- Standards and Regulations: CE marking, UL (CSA), RoHS.
- Material of Wetted Part: PPS, SUS304, FKM, SCS13 (Metal attachment); PPS, FKM, CPVC (Vinyl chloride piping).
- Piping Port Size: Various options from 3/8 to 1 1/2.
- Weight: Varies by model and options (flow switch only, with temperature sensor, with flow adjustment valve, with both, with lead wire).
Temperature Sensor Specifications:
- Rated Temperature Range: 0 to 100 °C.
- Setting/Display Temperature Range: -10 to 110 °C.
- Min. Setting/Display Unit: 1 °C.
- Display Unit: °C.
- Display Accuracy: ±2 °C.
- Analogue Output Accuracy: ±3%F.S.
- Response Time: 7 s.
- Ambient Temperature Characteristics: ±5%F.S.
Usage Features
- Integrated Display: The device features a 2-color main display (red/green) for instantaneous flow and a white sub-screen for accumulated flow, set values, peak/bottom values, fluid temperature, and line names. The display can be rotated for optimal viewing.
- Easy Setting: Settings are performed using three buttons (UP, SET, DOWN). The "3 step setting mode" allows for quick adjustment of set values, while the "Function selection mode" provides access to detailed settings for various functions (output mode, response time, external input, analogue output, power saving, security code, line names, output check, and reset to default).
- Display Color Customization: The display color for OUT1 can be set to change based on its ON/OFF status (e.g., Green when ON, Red when OFF).
- Power Saving Mode: Reduces power consumption by turning off the display after 30 seconds of inactivity, with decimal points flashing to indicate the mode.
- Key-lock Function: Prevents accidental changes to settings. Set values can still be viewed in key-lock mode.
- Line Name Input: Allows users to input up to 6 English characters or numbers to identify the piping line.
- Output Check Function: Enables manual ON/OFF control of the switch output (and analogue output) for wiring and circuit verification, independent of flow conditions.
Maintenance Features
- Retained Settings: All settings are retained even after a power cut or unexpected power removal, ensuring consistent operation upon restart.
- Regular Maintenance: Regular inspections are recommended to prevent unexpected malfunctions.
- Cleaning: Use a soft cloth for cleaning. For heavy stains, a cloth soaked with diluted neutral detergent and thoroughly squeezed can be used, followed by a dry cloth. Avoid solvents like benzene or thinner, as they can damage the surface and erase indications.
- Accumulated Flow Storage: The device can store accumulated flow values in permanent memory every 2 or 5 minutes, preventing data loss during power interruptions. The memory device has a writable limit of 1 million cycles.
- Reset to Default Settings: A function is available to restore all settings to their factory default values.
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