- How long would it take to update a network with 16 nodes of 256 digital I/O (4096 total points)?
16.2 MS
- What is the best and worst case repeatability of this configuration?
Because INTERBUS is a serial ring shift register, and each module is assigned to a time slot in a total frame protocol, the scan time does not vary. The network is inherently deterministic for both real time process data and for intelligent device parameter (PCP) data.
- How long would it require to update a network with 256 analog I/O points?(16 bit words)
16.2 mS
- What is the best and worst case repeatability of this device configuration?
Because INTERBUS is a serial ring shift register, and each module is assigned to a time slot in a total frame protocol, the scan time does not vary. The network is inherently deterministic for both real time process data and for intelligent device parameter (PCP) data.
- How would loss of the token change the determinism of network communications? For systems that do not use a token passing mechanism explain how a communication fault is recovered from and its impact on determinism.
INTERBUS does not use a token. The master has the capability to issue a command to switch the device causing the communications fault off, restart the bus, and communicate with all modules up to the defective one, or switch off the bus terminal branch segment, restart the bus, and communicate with all modules in the system except modules located in the switched off bus terminal branch segment.
- Can the Bus support change of state signaling?
No, it is not necessary. INTERBUS has sufficient bandwidth to transfer all I/O data to/from the master on every scan.
- How well will this implementation scale with respect to improvements in raw bit rate transmission?
Increasing baud rate will increase throughput proportionally. Lower baud rates are more immune to electrical noise, have longer transmission distances, can utilize alternate transmission media (slip rings, infrared, slotted waveguide) and do not require special low capacitance cable.
- Can portions of the network be scanned more frequently than the entire system?
No, data flows through every INTERBUS device in the serial shift register ring. If increased performance is desired, multiple masters can be inserted in the PC or PLC.
- Is message prioritization implemented?
Not necessary. Each module is allocated a time slot in the INTERBUS total frame protocol. Transmission of messages via the PCP protocol has no effect on the I/O process data update times.
- Can larger consecutive blocks of data be moved using block transfer?
Yes, via the Peripheral Communications Protocol (PCP) within INTERBUS. A single PCP message can be up to 244 bytes long. Multiple messages can be used to transfer larger data blocks. Each intelligent slave device can transfer this file 1, 3 , or 7 words at a time (plus 1 byte of overhead data) per each bus scan. This allows you to balance the amount of data to be transferred with the desired throughput.
Performance Metrics
