Meet the Axon: S505 and S515

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17/6/18 Products featuring analog I/Os are among the most popular products in our sortiment. We thus included them into Axon product line as well; not only in one, but in two variants! Meet the Axon S505/S515, featuring a combination of analog I/Os and compact S-line dimensions! 

S505/515 basic features

  Axon S505 Axon S515
Digital inputs - -
Digital outputs - -
Relay outputs - -
Analogue inputs 4 4
Analogue outputs 4 4
RS485 line 1 1
RS232 line - 1
1-Wire bus 1 -


As parts of the Axon 500 line, models S505 and 515 feature an architecture focused on analogue I/Os. Both models thus offer 4 analogue inputs and 4 analogue outputs while retaining usual communication interfaces and compact dimensions typical for the Axon S line. As with S205/215 models (featured in the previous article), S505 and S515 models also have an identical I/O architecture and differs only in communication interfaces - the S505 features a single 1-Wire bus, while the S515 exchanges the 1-Wire for a single RS232 serial line

Inputs & Outputs

Analogue inputs are designed for a reading of 0-10V voltage or 0-20mA current. Alternatively, the user can use AI for reading data from corresponding resistance sensors (such as the PT1000 thermal sensor). Specific measuring type can be set through a corresponding control software.  A typical example of practical use of analogue inputs is a connection of various analogue sensors - accelerometers, light intensity sensors, pressure meters, acoustic sensors etc.

Analogue outputs serve for controlling of external devices via 0-10V voltage. That allows the user to control and regulate various multi-state devices such as three-way valves, heat exchangers, water heaters etc. Switching between the current and voltage signal is performed via the control software. It is also possible to measure resistance (see below)

Additional functionality

Analogue inputs allow the user to perform precise voltage, current or resistance measurements

  • voltage measurement 0-10 V (16bit resolution)
  • voltage measurement 0-2.5 V (24bit resolution)
  • current measurement 0-20 mA (16bit resolution)
  • resistance measurement (from PT100, PT1000 or NTC sensors) using three-wire (0-100 Ω, 24bit resolution) or two-wire (0-1960 Ω, 24bit resolution) connection

On analogue outputs, the user can set output voltage. 

Communication interface

S205/215 are both equipped with the RS485 serial line for connecting of external devices or extension modules (i.e. the Neuron xS line). One line can be used for communication with up to 256 devices, using the Modbus RTU protocol. 

1-Wire bus featured on the S205 is used for reading data from corresponding 1-Wire sensors (humidity sensors, temperature sensors etc.). One bus can receive data from up to 15 sensors.

S215 has the 1-Wire replaced by the RS232 line. This serial line is used for asynchronous short-range communication with fixed transmission speed and is often utilized to communicate with older external devices or to connect converters for communication with other technologies.

Practical use example

S505 and S515 are suitable for smaller HVAC-focused household automation projects. Below is an illustrative use of S505/515's inputs, outputs and communication interfaces: 

Analogue inputs: a suite of analogue sensors (flow meter, resistance meter, pressure meter)

Analogue outputs: control of heat pump, heat exchanger

1-Wire bus: a set of temperature and humidity sensors, both indoor and outdoor

RS485 serial line: used for smart energy meter

RS232 serial line: used for connection of a touchscreen control panel

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