NOTE: This product has gone out of production and is replaced by the ML417.




The MLN315 family of remote telemetry units (RTUs)from YDOC (Your Data Our Care)  are powerful, flexible and remarkably easy to configure. The units are built in to an IP67 rated enclosure. An antenna is fitted to the main printed circuit board and an external antenna may be fitted if  the units are to be used in locations with poor signal strength.




The RTU offersa wide range of inputs: 3 pulse/state change inputs, multi-channel  Serial inputs (SDI-12 and MODBUS), two off 4-20 mA channels, two off analogue voltage inputs and an accessory port which may be used to connect a number of optional accessories.


DC, LI and PV


There are three primary power supply options, each of which uses a different front cover. The DC cover allows the unit to be powered from any 9 to 30 V DC power source and two variants are available: an AA model which utilises a set of three AA sized NiMH rechargeable batteries; and two LI versions which use either 1 or up to 3,  single use D sized  18 AH battery (which takes over if the power source fails). The PV model has a built in 1W solar panel which charges a set of NiMH AA cells
And if you find that the 1W panel is not enough to run your sensors, we can supply 2W and 5W solar versions.


Pulse Inputs


The RTUs carry three pulse inputs which may be used to monitor pulse flow meters, rain gauges etc. Pulse inputs can be recorded as count over a unit of time, as a totaliser or as a rate. They may also be used to detect a change in the state of an event i.e. for alarming.


Serial Inputs


The Serial input may be used to connect to SDI-12, RS232 or RS485 sensors. This opens up the RTUs to use with an extremely wide variety o f “smart sensors”.


Accessory Port




gps_rx_100 iridium_100


The Accessory Port (ADS model only) is used to connect to a variety of YDOC accessories (only 1 per RTU) :
- GPS: a compact GPS receiver designed to connect to the RTU allowing it to be used to track moving assets
- Camera: a high resolution camera with IR LEDs for night time use. Captures images and sends them to an FTP Server
- Satellite Modem: an Iridium satellite modem which allows the RTU to be deployed in areas where no mobile coverage is available. The RTUs can be configured to fall back to the satellite service is mobile comms fails. Users no longer have to buy two devices - one for satellite and one for mobile comms - as they can simply purchase the MLN315ADS and add the Iridium modem when  the unit is being used on sites without mobile coverage




By default the RTUs send data to a computer running the YDOC Insights software via a TCP-IP connection. If you want to send the readings to your own server, then install  YDOC’s TCP server module. It will collect the readings from the RTUs and also allow you to open a remote comms session for configuration and testing. The data can be downloaded in YDOC’s native format, in CSV format or in JSON format  The RTUs can also send data to an FTP server or as an attachment to an Email. These transfers can be used in isolation or in tandem.


Calculated Channels


Once you have configured the RTU, you can then create new calculated channels which are based on the values of one or more of the existing channels. The calculation module supports a range of 1, 2 and 3 variable functions and can utilise any existing sensor as an input.
There are also occasions where you will need to perform aggregation, for example when calculated average, maximum and minimum wind speeds. To this end, the RTUs also support Aggregated channels. Simply select the input channel, choose the scanning period and then decide on the calculations you wish to perform. The aggregated values then become available as saved channels.




Alarms may be set on the value of any of the internal or external sensor channel, or on the value of a calculated channel . Two levels of alarm are available for both low and high conditions. When an alarm is triggered the units may send an SMS to one or more recipients. Further alarms may be generated from within the YDOC Insights software once the data reaches it




MQTT (Message queuing telemetry transport) is an efficient, open protocol for exchanging sensor data. Clients (RTUs) which are attached to sensors, send  data to a Broker, which subscribes to the message or data stream. Similarly applications can use MQTT to read in data for presentation to end users. MQTT has quickly become the protocol of choice in the rapidly growing Internet of Things (IoT) sector. By turning on the MQTT output option in the RTU you can now send your current or logged readings to any MQTT friendly application - be it one running on a Cloud Server or on your Smart Phone.