C1300 by Beckhoff

The C1300 interface card is produced by Beckhoff as part of the C1 Interface Cards series. Designed for VMEbus installations, the board links a VME host to decentralized I/O stations through the II/O Lightbus System. By presenting a shared memory window to the CPU, the card enables deterministic data exchange among motion controllers, sensors, and actuators in industrial automation environments.

Up to 254 Lightbus modules can be addressed per card, allowing extensive node expansion without additional bus couplers. The onboard dual-port RAM offers 3 Kbytes of direct process data capacity, and each cyclic transfer sends a 32-bit payload in 25 µs, making the interface suitable for high-speed motion and time-critical I/O tasks. For firmware buffers and diagnostic flags, the hardware provides a separate DPRAM segment with a capacity of 2 K × 8 bits. During every transaction, the controller exchanges a handshake field of 255 bytes per channel so the host can acknowledge receptions and schedule subsequent telegrams. Block transfer is not supported; instead, all communication relies on fixed-length telegrams to keep latency predictable.

Within the VME memory map, the card occupies a 4 Kbyte host address window that can be placed in A24 space using the selectable A24/D16 or A24/D08 slave modes. Four programmable request lines generate up to 4 vectored interrupts through the D08 VME interrupter, providing deterministic service times without polling. Serial communication between the Lightbus transceiver and the optical ring operates at a sustained rate of 2.5 MBaud and is synchronized by the bus master. All logic and optoelectronics are powered directly from the VME backplane supply. The board measures 100 mm × 160 mm, matching the Eurocard format established in VMEbus Rev. C1 and fitting standard card cages alongside motion controllers and PLC CPUs.