DirectLine DL425 ppb Transmitter

Honeywell’s DirectLine DL425 ppb Transmitter is used to measure dissolved oxygen. Its compact design combines advanced microelectronics and Honeywell’s unique sensing technologies, for use in a wide range of applications including boiler feedwater in power plants. ​

What Is It?

​The DL425 ppb Transmitter measures dissolved oxygen accurately in applications where low levels of dissolved oxygen are present. Intrinsically safe, its corrosion-resistant sealed composite enclosure protects it from harsh industrial environments. The remote mounting option connects the electronics module to the DO probe via a cable for submersion or special mounting applications.

Its plug-in modular design allows safe removal and easy replacement of the probe. A ½-inch NPT conduit connection increases protection and noise immunity of the output cable. The transmitter module can be mounted integrally or remotely with the DL5000 probe on a 2-inch pipe, wall or DIN rail.

Apart from air and sample calibration options that reduce calibration time, the device includes a playing card-sized guide for simple, correct and consistent calibration and configuration.

How Does It Work?

​The DL425 ppb transmitter consists of an electronics transmitter module and a sensor that can be mounted integral to the transmitter or remotely eliminating the need and additional cost of a separate analyzer or transmitter.

For fast reliable probe accuracy check, the probe must first be removed from the process and exposed to air. The soft keys on the transmitter’s front case can then be used to initiate the air calibration procedure. The LCD display provides local process ppb O2 readouts for quick processing, while electronics and probe diagnostics reduce troubleshooting times.

What Problems Does It Solve?

​Honeywell’s DirectLine DL425 ppb Transmitter enables accurate measurement of low levels of dissolved oxygen in boiler feedwater in power plants to minimize corrosion of piping and turbines. It simplifies installation design and minimizes cable and panel construction costs. The transmitter’s direct 4-20 mA output makes it easy to set up, operate and maintain, providing considerable savings over the device’s lifetime.