Creating an application with more than 4 Sync Managers
Since Version 1.8.0 the EtherCAT library supports more than 4 Sync Managers.
This chapter describes the necessary steps that must be performed in the Industrial Communication Creator (ICC) to support more than 4 Sync Managers.
Usually the following Sync Manager Configuration is used (and recommended by the specification):
Sync Manager | Type | Description |
|---|---|---|
0 | MBoxOut | Mailbox (Master to Slave) |
1 | MBoxIn | Mailbox (Slave to Master) |
2 | Outputs | Process Data (Master to Slave) |
3 | Inputs | Process Data (Slave to Master) |
Creating additional Sync Managers
Using Sync Manager 0 and 1 as Mailboxes is mandatory. However, the other Sync Managers can be freely configured.
In order to configure Sync Managers N for process data transfer, the following steps must be executed in the ICC:
create a new Subindex N + 1 for object 0x1C00 (Sync Manager Communication Type)
choose the communication type (input/output)
configure a start address in the Process Data RAM of the ESC
(keep in mind that Process Data Sync Managers occupy a RAM area that is three times their size)Outputs must trigger the Sync Manager watchdog
create a PDO Assignment Object for the Sync Manager (0x1C10 + N)
this object defines which PDOs will be assigned to the Sync Manager
create the Sync Manager Synchronization object (0x1C30 + N)
adjust the default value of Subindex 2 (Synchronization Type)
for Outputs or Inputs that do not belong to an Output: 0x01
for Inputs that belong to an Output: 0x20 + Sync Manager Number of corresponding Output
Defining Sync Units
It is possible to restrict the usage of PDOs to a Sync Unit (pair of Output and Input) in the ICC:
select to corresponding PDO Assignment object of a Sync Manager (0x1C10 + N)
enable “Select Sync Unit“
enter a Sync Unit ID
assign another Sync Manager to the same Sync unit ID
for each desired PDO Maping object (0x1600 .. 0x17FF and 0x1A00 .. 0x1BFF):
enable “Select Sync Unit“
enter the corresponding Sync Unit ID