In modern industrial processes, measurement data must be accurate, accessible and easy to integrate into automation systems. Applications such as humidity monitoring, temperature measurement, dew point control, carbon dioxide monitoring, vaporized hydrogen peroxide measurement, moisture in oil analysis and liquid concentration measurement require flexible transmitter platforms that can support different sensor technologies.
The Vaisala Indigo520 Transmitter is designed for this purpose. As part of the Indigo500 Series, it provides a robust industrial interface for Vaisala Indigo-compatible probes and selected compatible devices. With support for two detachable measurement devices, multiple analog outputs, relay outputs, Modbus TCP/IP, web interface, data logging and optional cloud connectivity, Indigo520 offers a versatile solution for demanding process and environmental measurement applications.
What Is Vaisala Indigo520?
The Vaisala Indigo520 is an industrial-grade transmitter designed for use with Vaisala Indigo-compatible measurement probes. It can accommodate one or two detachable measurement devices simultaneously, allowing users to combine different measurement parameters in one transmitter platform.
The transmitter can be used with probes for humidity, temperature, dew point, carbon dioxide, vaporized hydrogen peroxide and moisture in oil. With an optional module, it can also measure barometric pressure.
In addition, Indigo520 can be connected to selected Polaris™ PR53 process refractometers for liquid concentration measurement, making it suitable for both environmental monitoring and process instrumentation applications.
Flexible Probe Compatibility
One of the strongest advantages of the Indigo520 is its wide compatibility with Vaisala measurement devices. It supports HMP Series humidity and temperature probes, DMP Series dew point probes, GMP250 Series carbon dioxide probes, HPP270 Series vaporized hydrogen peroxide probes and the MMP8 moisture in oil probe.
The supported probe models include HMP1, HMP3, HMP4, HMP5, HMP7, HMP8 and HMP9 for humidity and temperature; TMP1 for temperature; DMP5, DMP6, DMP7 and DMP8 for dew point; GMP251 and GMP252 for carbon dioxide; HPP271 and HPP272 for vaporized hydrogen peroxide; and MMP8 for moisture in oil.
This broad compatibility allows industrial users to standardize their measurement interface while selecting the correct probe for each process condition.
Two Measurement Devices in One Transmitter
The Indigo520 can support two detachable measurement devices at the same time. This is especially useful when a process requires multiple parameters, such as humidity and temperature, dew point and pressure, or moisture in oil and another process variable.
The probes are self-contained and interchangeable measurement instruments. They can be detached from the transmitter for calibration or maintenance, helping reduce downtime and simplify service work.
Probe connection cables can be extended using standard instrumentation cable, allowing up to 30 m / 98 ft distance between the transmitter and the probe. This provides installation flexibility when the measurement point and display or control connection point are not in the same location.
Analog and Digital Interfaces
Indigo520 offers strong integration capability for automation systems. It includes four configurable galvanically isolated analog outputs. These analog channels can be configured as current or voltage outputs.
Selectable current outputs include 4–20 mA and 0–20 mA, while selectable voltage outputs include 0–1 V, 0–5 V and 0–10 V. Outputs are scalable, allowing users to adapt the signal range to the automation system.
The transmitter also includes two configurable SPDT relays, which can be assigned to output parameters from connected probes. Relay outputs can be used for alarm functions, control signals or process safety indications.
For digital integration, Indigo520 supports Modbus TCP/IP over Ethernet. This allows measurement data to be transmitted directly to industrial automation systems, SCADA platforms or data acquisition systems.
Web Interface and Remote Monitoring
The Ethernet connection provides access to a web interface. This makes configuration, monitoring and diagnostics easier for users and maintenance teams.
Indigo500 Series transmitters can also be ordered with Vaisala cloud connectivity for remote monitoring. This option allows measurement data to be accessed remotely when the transmitter is configured for cloud connection and the required network conditions are met.
For industrial facilities with distributed measurement points, this remote access capability can support predictive maintenance, centralized monitoring and faster troubleshooting.
Data Logging Capability
The Indigo520 includes integrated data logging for all measurement parameters. The device uses non-volatile memory and can provide at least 10 years of storage when logging at a 24-hour interval.
This is valuable for process documentation, quality audits, environmental monitoring and long-term trend analysis. Users can track measurement history directly from the transmitter platform instead of relying only on external data acquisition systems.
Robust Industrial Design
The Indigo520 is built for industrial environments. It has an IP66-rated corrosion-resistant metal enclosure, making it suitable for demanding field installations and wet locations.
The housing material is AlSi10Mg, and the optional touchscreen display uses strengthened IK08 glass. The overall housing classification is IK08.
The transmitter weighs approximately 1.5 kg and has compact dimensions of 142 × 182 × 67 mm. These dimensions make it practical for wall, panel, pole or pipeline installation using the appropriate accessories.
Display and User Interface Options
The Indigo520 can be supplied with a 5-inch capacitive touchscreen display or as a non-display model with LED indicator.
The display version allows measurements to be viewed directly at the installation point. The non-display version is recommended for installations exposed to direct UV light, outdoor installations and high-humidity environments.
Supported user interfaces include web interface, optional touchscreen display and optional Vaisala cloud connectivity. Supported languages include English, Chinese, French, German, Japanese and Spanish.
Powering Options
Indigo520 offers multiple powering options. It can be supplied with protective extra-low voltage, AC mains power or Power over Ethernet.
The protective extra-low voltage version supports 15–35 VDC and 24 VAC ±20%. The AC mains version supports 100–240 VAC, 50/60 Hz. The PoE version supports IEEE 802.3at Type 2 Class 4.
This flexibility allows the transmitter to be adapted to different plant standards and installation environments. It is important to note that analog outputs, analog input and relays are not available in PoE-powered transmitters.
Operating Environment
The Indigo520 is suitable for outdoor use and wet locations. Its operating humidity range is 0–100% RH.
The operating temperature depends on the model configuration. With display, the operating temperature range is -20 °C to +55 °C. Without display, the range is -40 °C to +60 °C. Without display and with the barometer module, the range is -40 °C to +55 °C.
The IP66 rating and wide environmental tolerance make the transmitter suitable for industrial process areas, environmental monitoring points and demanding field installations.
Optional Barometric Pressure Measurement
Indigo520 can be supplied with an optional Vaisala BAROCAP® barometric pressure sensor, known for high accuracy and long-term stability.
The barometric pressure module has a pressure range of 500–1100 hPa. Total accuracy over -40 °C to +60 °C is specified as ±0.15 hPa, with long-term stability of ±0.1 hPa per year.
This option is valuable in applications where pressure compensation or accurate barometric pressure monitoring is required.
Compatible Devices Beyond Standard Probes
In addition to Indigo-compatible probes, Indigo520 can connect to other Vaisala devices. It can be used with the MHT410 Moisture, Hydrogen and Temperature Transmitter, Indigo80 Handheld Indicator, MGP260 Series Multigas Probes, and selected PDT101 / PDT102 differential pressure transmitters through analog input.
It is also compatible with Polaris™ PR53 process refractometers, including models such as PR53AC, PR53AP, PR53GC, PR53GP, PR53M, PR53SD and PR53W when ordered with the appropriate software configuration for process refractometers.
This makes Indigo520 a versatile transmitter platform for both gas-phase and liquid-process measurement applications.
Accessories and Installation Flexibility
The Indigo520 can be installed with several accessories, including an adapter plate, pole or pipeline installation kit, installation kit with weather shield and spatter guard.
Probe connection cables are available in lengths of 0.3 m, 1 m, 3 m, 5 m and 10 m. These accessories help users adapt the transmitter to different mechanical layouts and process environments.
The availability of cable glands, conduit fittings and service cables also supports practical installation and maintenance.
Compliance and Approvals
The Indigo520 complies with major industrial standards and directives, including EMC, Low Voltage and RoHS requirements. It supports electromagnetic compatibility according to IEC/EN 61326-1 for industrial environments.
The transmitter carries compliance marks such as CE, China RoHS, FCC, RCM and UKCA. It is also UL Listed for the USA and Canada and has type approvals including DNV GL certificate and EU RO Mutual Recognition certificate.
These approvals support use in demanding industrial and marine-related applications.
Why Choose Vaisala Indigo520?
The Vaisala Indigo520 is a strong choice for facilities that need a robust, flexible and future-ready measurement transmitter.
It supports multiple measurement technologies, two detachable devices, configurable analog outputs, relays, Modbus TCP/IP, web interface, data logging and optional cloud connectivity. Its rugged IP66 metal enclosure and wide operating temperature range make it suitable for demanding industrial conditions.
For users who work with Vaisala Indigo-compatible probes or Polaris PR53 refractometers, Indigo520 provides a centralized and scalable interface for measurement display, signal transmission and automation integration.
Conclusion
The Vaisala Indigo520 Transmitter is a versatile industrial transmitter for Indigo-compatible probes and selected Vaisala measurement devices. With support for humidity, temperature, dew point, carbon dioxide, vaporized hydrogen peroxide, moisture in oil, barometric pressure and process refractometer applications, it offers broad measurement flexibility from one platform.
Its four configurable analog outputs, two relays, Modbus TCP/IP, Ethernet web interface, data logging, optional touchscreen and IP66-rated metal enclosure make it a reliable solution for industrial automation, process monitoring and environmental measurement.
For plants that require accurate measurement integration, robust field installation and flexible connectivity, Indigo520 provides a powerful transmitter platform for modern industrial measurement systems.