ACDC - smart Communication Technology
ACDC (Analog Carrier for Digital Communication) is a patented technology for using the existing analog cabling of gas detection systems for digital data transmission. The advantage: The existing cables remain in place, transmit additional digital information in addition to the mere measured values, and can be used in the future to integrate portable detection devices into fixed systems.
The problem:
analog wiring in a digital world
By far the majority of gas detection systems installed today communicate via three-wire power lines (4-20 mA industry standard). While existing infrastructure is understandibly not being replaced cost reasons, smart sensors and transmitters today could provide far more information than can be transported to the controller via analog wiring.
The solution:
digital data transmission over existing systems
ACDC enables the use of the analog 4-20 mA lines to transmit digital information by superimposing amplitude modulation on the current signal. We use the proven Modbus protocol, which is already used in numerous digital GfG transmitters. With ACDC, transmission rates of up to 38,400 bit/s and distances of more than 1,200 metres are possible via analog cabling. ACDC is suitable for use in hazardous areas and allows retrofitting and gradual conversion to digital systems, as the existing analog cabling remains untouched. While measured values and additional information are transmitted digitally, the analog carrier signal serves as a backup in case of an error. This means safety all along the line.
The future:
integration of fixed and portable gas detection systems
The available bandwidth provides sufficient capacity to transmit more than just digital data from smart sensors and ACDC-enabled transmitters. The next logical step is the integration of portable gas detectors. Since they are equipped with radio transmitters, alarms and measured values can be conveyed to the fixed gas detection system. This creates a holistic safety concept based on analog wiring.
