IO Systems

IO Systems are connecting to sensors via various data transport layers. If you use the ZenClient::listSensorsAsync method, all IO systems will list the sensor they were able to auto-discover and you can connect to a sensor without knowing any additional details on the IO system.

In some case you may want to connect directly to a sensor because the sensor name is known. In this case, you need to also provide the name of the IO system the sensor is connected on.

Furthermore, some IO systems don’t support auto-discovery of sensors and they can only be used with the ZenClient::obtainSensorByName method.

SiLabs USB Express

LP-Research sensors which are configured to use the USB-mode can be connected via this IO system on Windows. The advantage is that the Baudrate does not need to be configured and the sensor can be configured via string name. This name is always the same, no matter on which USB port the sensor is connected or which other peripheral devices are connected.

Name in OpenZen

SiUsb

Supported Platforms

Windows only

Supports auto-discovery

yes

Example to obtain a USB connected sensor which has the name lpmscu2000573.

auto sensorPair = client.obtainSensorByName("SiUsb", "lpmscu2000573");

Windows COM Port

LP-Research sensors which are configured to use the COM port mode can be connected via this IO system on Windows. The baudrate needs to be provided with the call to obtainSensorByName and the sensor name is the COM-port named assigned to the sensor by Windows. This name can be different on different systems, depending how much other COM-Port devices are connected.

Name in OpenZen

WindowsDevice

Supported Platforms

Windows only

Supports auto-discovery

yes

Example to obtain a COM-Port connected sensor which is connected on the Windows COM-Port COM12 using a baudrate of 115200 bits per second.

auto sensorPair = client.obtainSensorByName("WindowsDevice", "COM12", 115200);

Bluetooth

The Bluetooth IO system can be used to connect to bluetooth sensors like the LP-Research LPMS-B2 sensor. To be able to connect to any bluetooth sensor, it first needs to be paired via the operating system’s device manager. Then it can be auto-discovered by OpenZen or directly connected via the bluetooth address of the sensor.

Name in OpenZen

Bluetooth

Supported Platforms

Windows, Linux, Mac

Supports auto-discovery

yes

Example to obtain a bluetooth sensor which has the bluetooth address 00:11:22:33:FF:EE:

auto sensorPair = client.obtainSensorByName("Bluetooth", "00:11:22:33:FF:EE");

Bluetooth Low-Energy

The Bluetooth Low-Energy IO system can be used to connect to bluetooth sensors like the LP-Research LPMS-B2 sensor via the low-enery mode of Bluetooth. To be able to connect to any bluetooth sensor, it first needs to be paired via the operating system’s device manager. Then it can be auto-discovered by OpenZen or directly connected via the bluetooth address of the sensor.

Name in OpenZen

Ble

Supported Platforms

Windows, Linux, Mac

Supports auto-discovery

yes

Example to obtain a bluetooth sensor which has the bluetooth address 00:11:22:33:FF:EE:

auto sensorPair = client.obtainSensorByName("Ble", "00:11:22:33:FF:EE");

Linux Device

Allows to connect to a sensor which is connected via the USB-mode on Linux systems. It is the equivalent of the SiUsb IO system on Linux in that it needs not baud rate configuration and only the device’s name to connect.

Sensors can only be connected on Linux if the user running the OpenZen process has read and write access to the serial devices of the system. To allow this, the users needs to be added to the dialout group. This can be done with this command:

sudo adduser <username> dialout

Name in OpenZen

LinuxDevice

Supported Platforms

Linux

Supports auto-discovery

yes

Example to obtain a bluetooth sensor which has the name lpmscu2000573

auto sensorPair = client.obtainSensorByName("LinuxDevice", "lpmscu2000573");

Network Streaming with ZeroMQ

This interface system allows to receive sensor data from another OpenZen instance over the network. Therefore, it does not connect to any local sensor but opens a network connection. Still, the received events are provided via the OpenZen event loop to the user and therefore appear like regular events from a local sensor. The ZeroMQ interface has some limitations in the features its provides for the sensor access. For example it does not support to start or stop streaming of the sensor or to reconfigure any settings on the sensor. Furthermore, ZeroMQ can not be used to query the components connected to the sensor.

On the machine where the sensor is physically connected to:

auto sensorPair = client.obtainSensorByName("SiUsb", "lpmscu2000573");
auto& sensor = sensorPair.second;
// publish sensor data via TCP to all hosts on port 8877
sensor.publishEvents("tcp://*:8877");

On the machine which should receive the sensor data over the network:

// connect to the remote instance of OpenZen running on the machine with the IP address 192.168.1.34
auto sensorPair = client.obtainSensorByName("ZeroMQ", "tcp://192.168.1.34:8877");

// now events received over the network can be queried via the normal OpenZen
// waitForNextEvent() call
const auto pair = client.get().waitForNextEvent();

Name in OpenZen

ZeroMQ

Supported Platforms

Linux, Windows, Mac

Supports auto-discovery

no