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CANopen Network Interface
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1606218 02 08/2006
"Node-Guarding" and "Life-Guarding" Monitoring Protocols
Introduction Error monitoring protocols are used to detect communication errors on the network.
The default monitoring method, "Node-Guarding", consists in the master controlling
the slaves. It is possible to add "Life-Guarding" control of the master by the slaves.
Definition of
"Life-Time"
The "Life-Time" parameter is calculated as follows:
"Life-Time"= "Guard-Time" x "Life-Time-Factor"
The object 100CH contains the ''Guard-Time'' parameter expressed in milliseconds.
The object 100DH contains the ''Life-Time-Factor" parameter.
Activation of
Monitoring
When one of the two parameters "Life-Time-Factor" or "Guard-Time" is set to "0"
(default configuration), the device does not perform monitoring (no "Life-Guarding").
To activate monitoring over time, you must enter a value (minimum 1) in the object
100DH and specify a time in ms in the object 100CH.
Common typical values for the "Guard-Time" parameter lie between 250 ms and 2 s.
Reliable
Operation
To enable reliable and secure operation, the user must enter a "Life-Time-Factor"
with a minimum value of 2.
When the value 1 is used, should a delay occur due to the processing of high priority
messages or internal processing on the "Node-Guarding" master, the device
switches back to the "Pre-Operational" default state without generating any errors.
Note: The simultaneous use of both monitoring methods, "Guarding" and
"Heartbeat", is impossible. Should both methods be activated at once, the
equipment will only use the "Heartbeat" monitoring method.
RISK OF UNINTENDED DEVICE OPERATION
Set the "Life-Time-Factor" (object 100DH) to a minimum value of 2 to prevent any
inadvertent change of state to "Pre-Operational" state. Depending on the I/O
configuration, an inadvertent change of state may result in unintended device
operation.
Failure to follow this instruction can result in death, serious injury, or
equipment damage.
WARNING