Technical information

Controller States and Behaviors

EIO0000000638 04/2012

z The Write Outputs operation continues. The %Q output memory variable is

updated to reflect either the Keep current values configuration or the Set all

outputs to default configuration, adjusted for any output forcing, and then

written to the physical outputs.

NOTE: Commands received by Ethernet, Serial, USB, and CAN communications

can continue to write to the memory variables. Changes to the %Q output memory

variables are written to the physical outputs.

CAN Behavior When Update IO While In Stop Is Selected

The following is true for the CAN buses when the Update IO while in stop setting

is selected:

z The CAN bus remains fully operational. Devices on the CAN bus continue to

perceive the presence of a functional CAN Master.

z TPDO and RPDO continue to be exchanged.

z The optional SDO, if configured, continue to be exchanged.

z The Heartbeat and Node Guarding functions, if configured, continue to

operate.

z If the Behaviour for outputs in Stop field is set to Keep current values, the

TPDOs continue to be issued with the last actual values.

z If the Behaviour for outputs in Stop field is Set all outputs to default the

last actual values are updated to the default values and subsequent TPDOs

are issued with these default values.

Task and I/O Behavior When Update IO While In Stop Is Not Selected

When the Update IO while in stop setting is not selected, the controller sets the

I/O to either the Keep current values or Set all outputs to default condition (as

adjusted for output forcing if used). After this, the following becomes true:

z The Read Inputs operation ceases. The %I input memory variable is frozen at

its last values.

z The Task Processing operation is not executed.

z The Write Outputs operation ceases. The %Q output memory variables can be

updated via the Ethernet, Serial, and USB connections. However, the physical

outputs are unaffected and retain the state specified by the configuration

options.

CAN Behavior When Update IO While In Stop Is Not Selected

The following is true for the CAN buses when the Update IO while in stop setting

is not selected:

z The CAN Master ceases communications. Devices on the CAN bus assume

their configured fallback states.

z TPDO and RPDO exchanges cease.

z Optional SDO, if configured, exchanges cease.

z The Heartbeat and Node Guarding functions, if configured, stop.

z The current or default values, as appropriate, are written to the TPDOs and

sent once before stopping the CAN Master.