CANopen DSP 305 Implementation Guide
3 LSS Services
LSS services can be functionally grouped into four categories:
Switch Mode Services provide a way to logically connect the LSS Master and LSS Slave(s) for configuration purposes. They change the LSS mode attribute of the LSS Slave (see the Figure
Configuration Services perform the actual task of configuring the layer parameters of LSS Slave(s). The configuration services are only available in configuration mode.
Inquiry Services provide a way for the LSS Master to determine layer parameters. The inquiry services are available only in configuration mode.
Identification Services provide a way for the LSS Master to determine the presence of a device and to check for devices with invalid
Configuration Mode | |
Switch Mode Global | Switch Mode Global |
Operation_Mode | Operation_Mode |
parameter with Node | parameter with Node |
I.D. unchanged | I.D. unchanged |
Operation Mode | |
Switch Mode global Operation Mode parameter with Node- ID changed.
Switch Mode selective with Matching LSS- address parameter.
Power-on
Reset
Node Diagram
Figure 3-1 LSS Slave Modes and Switching Services
3.1LSS Master-Slave Synchronization & Protocol
In the LSS Protocol all slaves use the same Communications Object (COB) to send information to the LSS Master. In order to ensure that only one LSS Slave communicates with the LSS Master at a time, a switching mechanism, under the control of the LSS Master is implemented.
A slave can only communicate with the Master after it has been switched into Configuration Mode by the master. In other words, the Master must first take the initiative. Furthermore, the Slave only communicates specific information requested by the Master.
