Communications
Instrumentel’s products offer the ability to communicate using a magnitude of industry standard protocols and interfaces. Instrumentel has considerable experience in dealing with communications, ensuring that an appropriate communications protocols is matched to the problem in hand. Instrumentel can create and configure custom protocols upon request. As would be expected Instrumentel offer the following standards and options in all products.
Physical Interfaces
Ethernet, 10/100 BASE-T IEEE802.3, is a popular choice due to its speed and reliability. With the use of the TCP/IP protocol, Ethernet offers a resilient communication medium. Instrumentel also offers the facility to power their devices using Power over Ethernet (POE) IEE802.3af. Using POE an Industrial device can be networked using single cable for both data and power. Upon request Instrumentel can also provide system components which satisfy CAT1B safety requirements.
WIFI 802.11b/g is extensively used in industry to wirelessly connect devices. Industrialised Wi-Fi compliant equipment is readily available this enables wireless solutions to be deployed quickly and cost effectively. Wi-Fi can be used in a TCP/IP network, so offers similar communication resilience to Ethernet.
Bluetooth operated in the unlicensed 2.4 GHz band is primarily designed for low power consumption and short range (power-class-dependent: 1 meter, 10 meters, 100 meters). The features offered through Bluetooth are limited when compared with Wi-Fi, however Bluetooth does offer cost effective wireless connectivity; as it is cheaper than Wi-Fi Bluetooth can be used if a short-range wireless connection to a device is required. Connections to an Instrumentel device can be made using a Bluetooth enabled PDA or laptop. In addition to this, using suitable hardware, Bluetooth enabled Instrumentel devices can be accessed from a TCP/IP network.
ZigBee is a low-cost, low-power, wireless mesh networking proprietary standard. Designed for a similar market to Bluetooth, ZigBee is both small and low-power. It was designed primarily for Wireless Personal Area Networks (WPANs), such as wireless headphones and/or connecting with cell phones via short-range radio. The technology defined by the ZigBee specification is intended to be simpler and less expensive than other WPANs, such as Bluetooth. ZigBee is targeted at Radio-Frequency (RF) applications that require a low data rate, long battery life, and secure networking.
Instrumentel has developed and deployed a Zigbee network used to control a distributed sensor network. In this case the advantage of proved to be its ability to be configured in a mesh network, providing a network with the ability to self-heal. A flock of ZigBee equipped devices are able to re-organise themselves if a node is lost. The low power consumption and fast start up times for ZigBee devices also makes it a suitable choice for field deployment. An example of this deployment was used in the ISSB project.
The Controller–Area Network bus (CAN or CAN-bus) is a vehicle bus standard designed to allow microcontrollers and devices to communicate with each other within a vehicle without a host computer. CAN is a message based protocol, designed specifically for automotive applications but is also used in other areas such as industrial automation and medical equipment.
Instrumentel has experience of interfacing to automotive systems using the CAN bus. The company has developed a number of CAN standard protocol libraries allowing solutions to be deployed very rapidly using this interface. An example where instrumentel has used this technology is the Bloodhound SSC project.
Modbus is a serial communications protocol and is one of the most common means of connecting industrial electronic devices. Modbus allows multiple devices connected to communicate over the same network. An example where modbus is currently used is on production line test environments. Here multiple types equipment are connected to one bus and communicate to a central Personal Computer. Modbus is used extensively in the rail industries, so to provide tangible solutions for the rail industry it is necessary for Instrumentel to provide this as an option on its products.
Protocols
TCP/IP is a very resilient communication protocol, capable of handling bit shifts, lost packets, differing transmission routes, data stream re-construction to name but a few. The Internet uses this protocol and is testament to the level of data integrity offered by TCP/IP.
TCP/IP is complex, and when deployed on embedded devices utilises large amounts of a devices resources. Therefore careful consideration has to be made when deciding what devices have this level of communication structure.
The use of TCP/IP enables a device to communicate globally, using the Internet. Indeed TCP/IP can be routed over broadband, GSM, 3G, Dialup, Satellite and many other types of connection. Ethernet and WIFI generally use TCP/IP natively, with Bluetooth and Zigbee based infrastructures also being capable of using TCP/IP.
CAN based systems use a number of different standard protocols, for example J1939, OBDII. Instrumentel has the framework to develop interfaces to any CAN based protocol.
ModBus Applications include data logging on a remote Supervisory Control and Data Acquisition (SCADA) system, storing and analysing data and transmitting via another method at a predefined time. This could be used for a remote pumping station or the Heating, Ventilation and Air-Conditioning (HVAC) system on a train.
