Digital Output Flow Meters from DDM Sensors

Our portfolio of digital output flow meters offers a wide range of technologies for precise measurement and control tasks. To help you navigate, here is an overview of the available digital interfaces, each leading to detailed descriptions:

Note: Navigation tiles linking to each section: TTL Output, Hall Sensor (NPN), Reed Sensor, Namur Sensor, NPN Pulse Output, PNP Pulse Output, Transistor/Pulse Output, IO-Link, CAN Bus.

Detailed Overview of DDM Sensors Digital Output Signals

Flow Meters with TTL Output

An output signal based on Transistor-Transistor Logic (TTL) provides defined voltage levels for the logical “High” and “Low” states. This clear signal definition allows direct connection to microcontrollers, frequency counters, and digital logic circuits without needing additional signal converters.

At DDM Sensors, we offer the following flow meters with TTL output:

• VCT Series: Precision turbine flow meters (0.05 to 350 L/min)
• FLT Series: High-pressure turbine flow meters (up to 500 bar)

Also available is the ASP Smart-Pickoff, a retrofittable sensor pickup that equips existing turbines with a TTL output and integrated parameter memory. All listed models deliver a maximum output frequency of 2 kHz.

Hall Sensor (NPN)

The Hall sensor provides wear-free measurement acquisition, resulting in high durability and robustness. It outputs an NPN signal via an open-collector output switching to ground (GND).

This principle is utilized across our extensive range of oval gear flow meters:

• OG1 (available in stainless steel or PEEK)
• OG2
• OG3
• OG4
• OG5
• OG6
• OG7

These oval gear meters cover flow ranges from 0.01 L/min to 500 L/min and are rated for process pressures up to 700 bar. Furthermore, we equip our FT2 Hall radial turbine for opaque liquids and the NSF-certified NSF Beverage mini paddlewheel sensor with an NPN signal.

Reed Sensor

A Reed sensor provides a dry, potential-free contact actuated magnetically. This simple and robust technology is ideal for applications requiring volume pulse counting without an external power supply at the sensor. Due to its potential-free design, it can be used in combination with isolating switching amplifiers in explosion-proof (Ex) areas. We offer the pulse/frequency output (Reed contact) as an option for our entire line of oval gear meters, from OG1, OG2, OG3, OG4, OG5, and OG6 to OG7.

Namur Sensor

Namur sensors are two-wire proximity switches complying with the EN 60947-5-6 standard, outputting a current-controlled signal. Their primary purpose is to ensure intrinsic safety in hazardous, explosion-prone areas.

By limiting current and voltage within the signal circuit, the generation of spark energy capable of ignition is prevented. This safety-critical output variant is available for all our heavy-duty stainless steel oval gear series: OG1, OG2, OG3, OG4, OG5, OG6, and OG7.

NPN Pulse Output

The NPN pulse output is an open-collector output switching to ground, providing a frequency proportional to the flow rate. It is an established industrial standard for connecting to digital counters, data acquisition systems, and PLC frequency inputs.

This output signal is available across a broad spectrum of our flow meters, including:

• Paddlewheel Meters: Beverage Meter, FT2 Optical, 800, 900, and 1000 Series
• Ultrasonic Flow Meters: Process Atrato, Atrato, MetraFlow (2x NPN)
• All Oval Gear Meters

Additionally, our portfolio features the Pulsite Link converter, which converts standard flow meter pulse outputs into linearized analog and NPN/PNP outputs.

PNP Pulse Output

The PNP pulse output, also known as a “sourcing” output, switches the signal to the positive supply potential (+V). As with the NPN output, the emitted frequency is directly proportional to the flow rate. This output type is a widely adopted standard in European automation engineering and is natively supported by many PLC digital input cards. We provide PNP pulse outputs on the 800, 900, and 1000 turbine series, the Process Atrato, Atrato, and MetraFlow (1x PNP) ultrasonic sensors, the Pulsite Link converter, and optionally on all oval gear meters.

Transistor / Pulse Output

A flexible transistor or pulse output is characterized by its configurability, particularly regarding the pulse rate (pulses per unit volume). This adaptability makes it a versatile solution for precise batching and dosing tasks, where pulse weightings must match the downstream PLC input specifications exactly.

The battery-powered Pulsite Solo display unit features an optional scaled transistor output. The electromagnetic flow meter JUMO flowTRANS MAG H20 also includes a digital transistor/pulse output alongside modern interfaces like IO-Link.

IO-Link

IO-Link is a standardized, intelligent point-to-point communication protocol according to IEC 61131-9, enabling bidirectional data exchange between the sensor and control level. Beyond transmitting real-time process values, this interface allows remote parameterization, retrieval of detailed diagnostic data, and event reporting (e.g., threshold limit alerts).

We implement this technology in our JUMO flowTRANS MAG H20 and JUMO flowTRANS US W02 flow meters. The MAG H20 also features Bluetooth and NFC interfaces for effortless app-based configuration.

CAN Bus

The CAN bus (Controller Area Network) is a serial, real-time communication bus system compliant with ISO 11898. Differential two-wire transmission makes the signal highly immune to electromagnetic interference. Because multiple nodes communicate over a single shared line, wiring complexity is significantly reduced.

With the VCA-CAN flow computer, we provide a digital CAN bus signal conforming to the CAN 2.0B (High Speed) standard. The VCA-CAN can be combined with both our turbine flow meters and our oval gear flow meters.

Advantages of Digital Flow Meters from DDM Sensors

Digital flow meters from DDM Sensors deliver decisive advantages for modern industrial automation:

• High Noise Immunity: Digital signal processing guarantees high noise immunity and excellent signal quality, ensuring precise, loss-free data transmission from the sensor to the controller. This greatly simplifies integration into PLC and IIoT architectures.
• Diagnostics & Parameterization: Advanced interfaces like IO-Link unlock extended diagnostic and remote parameterization capabilities directly in the field or from a central control room.

Performance Features of DDM Sensors Flow Meters

Our digital output flow meters deliver high performance across three core areas:

• Media Compatibility: Utilizing wetted materials such as stainless steel (316L), PEEK, PVDF, and PPS, our sensors handle water, oils, coolants, chemically aggressive fluids, and high-purity media. Dedicated designs, such as our oval gear meters, are optimized for viscous liquids.
• Measuring Ranges: Featuring scalable measuring principles, our portfolio covers the full spectrum from micro-flows as low as 0.002 L/min (Atrato ultrasonic sensor) up to high flow rates of 1200 L/min (FLT high-pressure turbine).
• Accuracy: Offering repeatabilities down to ±0.025% (e.g., VCT series) and measuring accuracies up to ±0.5% of reading (e.g., OG4 series), our devices guarantee reliable, highly accurate data acquisition for critical industrial processes.

Application Areas for DDM Sensors Flow Meters

In machine and plant engineering, DDM Sensors flow meters monitor cooling and lubrication circuits. In water treatment and distribution, they ensure precise volumetric metering. The high chemical resistance of many models makes them the preferred choice for process engineering and the chemical industry. In dosing and filling systems, their accuracy and repeatability safeguard product quality. Furthermore, our precision sensors are widely integrated into test benches and quality assurance setups where reliable test metrics are essential.

Selecting the Right Flow Meter for Your Application

To ensure you receive the most effective and cost-efficient solution for your specific application, contact our technical specialists to discuss measuring ranges, electrical interfaces, or explore our custom flow meters to find the ideal sensor series for your project.