Vaisala Indigo520 Transmitter
Overview
Vaisala Indigo520 is an industrial-grade transmitter that accommodates one or two Vaisala Indigo-compatible probes and turns their measurements into local displays, analog signals, relays and network data. The probes can measure humidity, temperature, dew point, carbon dioxide, hydrogen peroxide and moisture in oil, and an optional barometric module adds pressure. The Vaisala Indigo520 supports any combination of two detachable measurement devices simultaneously and logs all measurement parameters, so one instrument can serve a process point that previously needed two separate transmitters.
Seven Star LLC supplies the Vaisala Indigo520 together with compatible probes to industrial, laboratory and facility customers in Oman and the GCC, with engineering support in Muscat. It is the natural companion for probes such as the HMP series humidity probes and for plants that already monitor humidity with the Vaisala HMT330 humidity and temperature transmitter and want a flexible, networked platform for new measurement points.
Probe-Based Transmitter Principle
In the Indigo concept the measurement is done by the probe and the transmitter is the interface. Each Indigo-compatible probe is a self-contained, interchangeable measurement instrument holding its own sensor, calibration data and electronics. The Vaisala Indigo520 reads the digital data from up to two probes, scales it, and assigns any output parameter of any connected probe to its analog channels, relays or Modbus registers. When a probe needs calibration or maintenance it can be unplugged and replaced without recalibrating the transmitter, which shortens downtime.
The transmitter provides four analog channels that can be configured as current or voltage and two configurable relays, together with an analog 4 to 20 mA input for third-party two-wire devices. Digital integration uses Modbus TCP/IP over Ethernet, and the Ethernet connection also hosts a web interface for viewing measurement data and, with the optional cloud connectivity, remote monitoring that meets modern cybersecurity standards. Through the service port the transmitter can be configured with the free Vaisala Insight PC software or the Indigo80 handheld indicator.
Engineering Design of the Vaisala Indigo520
The Vaisala Indigo520 housing is made of AlSi10Mg aluminium with a strengthened glass display window, impact resistance of IK08 and an IP66 rating, and it is classified UL 50E Type 4 as evaluated by Eurofins. The transmitter measures 142 x 182 x 67 mm, weighs 1.5 kg and is suitable for outdoor use and wet locations, with cable glands accepting cables from 2 to 9 mm depending on the gland type. With a display it works from −20 to +55 °C, and the version without a display, using an LED indicator, covers −40 to +60 °C and is recommended for direct UV exposure, outdoor installation and high-humidity locations.
Powering options include protective extra-low voltage at 15 to 35 V DC or 24 V AC, mains power at 100 to 240 V AC, and Power over Ethernet to IEEE 802.3at Type 2 Class 4. The PoE version has no analog outputs, analog input or relays. The optional BAROCAP barometric module measures 500 to 1100 hPa with total accuracy of ±0.15 hPa from −40 to +60 °C and long-term stability of ±0.1 hPa per year. The capacitive touchscreen presents graphs and trends for both probes.
Key Features
The Vaisala Indigo520 brings flexibility and connectivity to Indigo-compatible probes:
- Supports any combination of two detachable probes at the same time, with all measurement parameters logged inside the transmitter.
- Four configurable galvanically isolated analog outputs and two relays pass measurements to PLC and DCS systems and drive alarms.
- Ethernet connection with web interface and Modbus TCP/IP, plus optional Vaisala cloud connectivity for remote monitoring.
- Two-wire current loop analog input lets third-party analog devices be shown and logged alongside Vaisala probes.
- IP66 metal enclosure with IK08 glass window withstands outdoor use, wet locations and impacts.
- Three powering options, PELV, mains and Power over Ethernet, match different site infrastructure.
- Optional non-display model with LED indicator for outdoor, UV-exposed or high-humidity installations.
- Compatible with humidity, dew point, CO2, hydrogen peroxide, multigas and moisture-in-oil probes, so one transmitter platform covers many measurements.
Industrial Applications
The Indigo500 series is the most versatile option for Indigo-compatible probes. The Indigo520 fits pharmaceutical and life science facilities, cleanrooms, warehouses and cold stores, food production, drying and test chambers, compressed air stations and any plant that needs combined humidity, temperature and CO2 or dew point monitoring with logging. The Ethernet and Modbus TCP/IP connection suits building management and SCADA integration at industrial estates in Muscat, Sohar and Salalah, where central monitoring across several sites is increasingly required.
Seven Star LLC helps customers specify the probe combination, power version, display option and cable lengths of the Vaisala Indigo520, and can quote the HMP, DMP, GMP and TMP probes that connect to it. For ceiling or duct sensing needs in building systems teams may also compare it with the Siemens QFM1660 duct humidity and temperature sensor, and for dedicated dew point work with the Michell Easidew EA2 dew point transmitter. Request the Vaisala Indigo520 datasheet to review the compatible device list and ordering options.
Technical Specifications
Specifications of the Vaisala Indigo520 below come from the manufacturer datasheet. Some features depend on the powering and display options selected.
| Parameter | Specification |
|---|---|
| Model | Vaisala Indigo520 transmitter |
| Probe inputs | 1 or 2 Indigo-compatible probes |
| Analog outputs | 4 configurable, galvanically isolated, mA or voltage |
| Relays | 2 configurable |
| Analog input | 4–20 mA, two-wire current loop, ±0.05 mA |
| Digital interface | Ethernet with web interface, Modbus TCP/IP |
| Display options | Capacitive touchscreen or no display with LED indicator |
| Power options | PELV 15–35 V DC / 24 V AC; mains 100–240 V AC; Power over Ethernet |
| Enclosure | AlSi10Mg aluminium; IP66; IK08; UL 50E Type 4 |
| Operating temperature | −20 to +55 °C with display; −40 to +60 °C without display |
| Dimensions and weight | 142 x 182 x 67 mm; 1.5 kg |
| Optional module | BAROCAP barometric pressure, 500–1100 hPa |
Request a Quote for Vaisala Indigo520
To request a quotation for the Vaisala Indigo520, tell Seven Star LLC the probes you plan to connect, the powering option, display preference and communication needs. We supply the Vaisala Indigo520 with engineering support in Muscat and can share the Vaisala Indigo520 datasheet and compatibility list with engineering and procurement teams across Oman and the GCC.
- Datasheet Vaisala Indigo520 Transmitter Datasheet (B211735EN) Download
Vaisala product families
The Indigo line separates probe and transmitter. The Indigo520 takes two Indigo-compatible probes at once and offers four analog outputs, relays and Ethernet in a metal IP66 enclosure, with or without a touchscreen. The HMP7 humidity and temperature probe is one of the probes that connect to it. The HMT330 is the earlier one-piece humidity and temperature transmitter series, and the DMT152 is a compact transmitter for low dew points in dry gases.Ordering Vaisala instruments: what we need
Vaisala builds each unit to an order code. Send the full code, or the probe type, cable length, output signals, supply voltage, display option and the certificate type required. For dew point, give the expected range and line pressure.Browse Vaisala products by category: Temperature Instrumentation.

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