VARAN Bus key data

By using the Manager-Client principle, collisions are avoided. The VARAN bus provides highest speed, shortest cycle time and minimum synchronicity jitter. In addition, it offers the unique possibility of asynchronous direct access.  

Data packets are repeated within the cycle until a valid acknowledgment is received. Therefore, the validity of all data is guaranteed at the end of each cycle. This permanent testing of data validity, even for bus cycle times less than 100 µs, is only possible through use of the small VARAN data frames (1 – 128 bytes).

Highlights

Hard real-time	Cycle times < 100 µs, jitter < 100 ns - each instruction is immediately confirmed by the receiver
High data reliability and error tolerance	Unacknowledged messages are repeated within the same bus cycle
Flexible network topology	Modular machine structures using star, line or tree topologies
Economic	Costs comparable to a field bus connection through the use of inexpensive FPGAs for managers and clients
Open standard	The VARAN BUS USER ORGANIZATION (VNO) manages the open VARAN bus technology

Further Advantages at a Glance

Automatic addressing	Minimal network administration costs
Speed	High data transfer rates - higher scan rates - higher performance - increasing quality
Deterministic behavior	Bus participants are accessed in each bus cycle at exactly the same time
Direct access	Fast asynchronous direct access at any time
Hot plug capability	Participants can be added or removed during operation
Protocol completely implemented in the hardware	No additional load on the CPU
Simple implementation	Also in small sensors/actuators
Synchronization over PLL	Distributed clocks according to IEEE 1588 are not required
Multi Manager capable	RT-Networking of several autonomously operating systems
Tunneling of standard Ethernet	Standard TCP/IP communication is possible even with the shortest cycle times
Bus and power supply in one cable	Simple signal and power transmission through VNO- certified connectors and cables is possible
CANopen® mapping on the VARAN bus	Simple connection to existing CANopen® devices
Analysis and service made simple	With comfortable diagnostic and service tools

Performance data

	Bus cycle times < 100 µs Jitter < 100 ns Isochronous access time 1 Byte r/w 2,18 µs 16 Byte r/w (1 drive) 5,05 µs Asynchronous direct access 128 Byte r/w < 25 µs   Portable to Gigabit Ethernet without protocol changes