Multi-component apparatus and method for isochronous communication therein
In a method for isochronous communication of components of a multi-component apparatus, which communicate via peer-to-peer communication connections created by a switch, a periodic communication clock signal is provided by a control computer to all the components, with a communication window between two communication clock cycles of the communication clock signal, in which a communication information item of the isochronous communication is transferrable from a transferring component to at least one addressed component. A synchronization, in relation to the communication clock signal, between at least two of the components is produced by at least one synchronization message sent via the switch by one of the components to be synchronized to all the other components to be synchronized in a communication time window.
1. A method for isochronous communication among components of a multi-component magnetic resonance imaging apparatus, said components communicating via peer-to-peer communication connections produced by a switch, said method comprising:
providing a periodic communication clock signal, from a central computer, together with a higher-frequency system clock signal, to all of said components, said periodic communication clock signal comprising a plurality of successive clock cycles with a communication time window between two immediately successive communication clock cycles, in which a communication information item of the isochronous communication is transferrable from a transferring component, among said plurality of components, to at least one addressed component, among said plurality of components, wherein said communication clock cycles are coded in said system clock signal by pulse width modulation or amplitude modulation; and
producing a synchronization, relative to said communication clock signal, between at least two of said plurality of components by sending, via said switch, at least one synchronization method from one of said plurality components to be synchronized to all of the other components in said plurality of components to be synchronized, in said communication time window.
2. A method as claimed in claim 1 comprising using, as said communication connections, optical PCI Express connections.
3. A method as claimed in claim 1 comprising, with said switch, providing multicast peer-to-peer communication connections.
4. A method as claimed in claim 1 comprising, with said central computer, distributing an available bandwidth via said communication connections for the isochronous communication, via a mass communication.
5. A method as claimed in claim 4 comprising preparing said control commands in advance in said central computer, independently of the synchronization.
6. A method as claimed in claim 1 comprising, from said central computer, transferring at least one control command of a control command set to the components to be synchronized, for temporally coordinate cooperation of said components, with at least one execution time point being associated with each control command relative to said communication clock signal, and executing said control commands in the respective components dependent on the synchronization at their respective execution time points.
7. A method as claimed in claim 1 comprising, within a communication window:
transferring a time-related communication information item with at least one addressed component via at least one transferring component, as a synchronization message, to said switch;
transferring the communication information via the switch to said at least one addressed component;
receiving said communication information at said at least one addressed component; and
in said at least one addressed component, processing the communication information in a time-related manner dependent on said synchronization and on said communication clock signal.
8. A method as claimed in claim 7 comprising including, in said communication information, at least one execution information item related to said communication clock signal from a next communication clock cycle, or related to the synchronization, said execution information item describing an execution time and a control command contained within the communication information being implemented at said execution time.
9. A method as claimed in claim 1 comprising transferring said communication clock signal via a clock generator in a star configuration.
10. A method as claimed in claim 1 comprising transferring said communication clock signal via optical communication lines to said components.
11. A method as claimed in claim 1 comprising transferring the communication clock signal and said system clock signal overlaid on each other.
12. A method as claimed in claim 1 comprising, with each communication clock cycle, triggering a start of a time counter in a respective component that measures time points within said communication time window.
13. A method as claimed in claim 1 wherein the magnetic resonance imaging apparatus is a nuclear magnetic resonance imagining apparatus.
14. A multi-component magnetic resonance imaging apparatus comprising:
a plurality of components;
a switch for isochronous communication among said plurality of components via peer-to-peer communication connections produced by said switch; and
a central computer configured to provide a periodic communication clock signal, together with a higher-frequency system clock signal, to all of said components, said periodic communication clock signal comprising a plurality of successive clock cycles with a communication time window between two immediately successive communication clock cycles, in which a communication information item of the isochronous communication is transferrable from a transferring component, among said plurality of components, to at least one addressed component, among said plurality of component, wherein said communication clock cycles are coded in said system clock signal by pulse width modulation or amplitude modulation
wherein the switch is configured to produce a synchronization, relative to said communication clock signal, between at least two of said plurality of components by sending, via said switch, at least one synchronization method from one of said plurality components to be synchronized to all of the other components in said plurality of components to be synchronized, in said communication time window.
15. A multi-component magnetic resonance imaging apparatus as claimed in claim 14 wherein said multi-component apparatus is a magnetic resonance imaging apparatus and wherein said plurality of components, in combination, form respective portions of a control system for controlling imaging by said magnetic resonance imaging apparatus.
16. A multi-component magnetic resonance imaging apparatus as claimed in claim 15 wherein said components forming said control system include at least one of a gradient controller, a radio-frequency controller, a monitoring component, and a data acquisition component.
17. A multi-component magnetic resonance imaging apparatus as claimed in claim 14 wherein the multi-component magnetic resonance imaging apparatus is a nuclear magnetic resonance imagining apparatus.