Converteam GEMTEQ I/O GEM80, Technical Manual

Page: 37 / 103

GEMTEQ I/O 4. GEMCAN I/O Scanner Configuration
4.2.10 Node Guard Period (mS)
Module 1 (Port A Px+9, Port B Px+20) / Module 2 (Port C Px+38, Port D Px+49)
Range 1 to 32000 mS 0 = Default see table below
When configured as a master, the GEMCAN I/O Scanner periodically sends Node Guard
messages on the CAN network. These are used to test which slaves devices are present on the
network and also to enforce mastership of the bus to any other connected bus maseters. By
default the interval between these messages is dependant upon the Baud Rate.
Table 4-6 Default Node Guard Period
Baud Rate Default Node Guard Period (mS)
1M 10
800k 20
500k 40
250k 80
125k 160
100k 320
50k 640
20k 1280
10k 2560
If required, the default timing can be overridden by entering a value into this parameter. This
value is the time between Node Guard events to slave devices on the network.
It is the lack of Node Guard messages that initiate a GEMTEQ I/O module detects and causes
it to go into freeze/fallback mode, and also bus master change-over
Each slave node will be node guarded according to the node guard period. The time to node
guard all nodes within a GEMTEQ network is calculated by the following:-
n x T where n= Number of nodes configured and T= Node Guard period
Therefore care must be taken to ensure that a modules freeze/fallback time is not less than
the time taken to be node guarded (see appendix C ). A change-over Master configuration
also uses the loss of node guard message to initiate a change-over, again care must be taken
to ensure that this is not less than the change-over period as detailed in section 4.2.5.
Please refer to application note Appendix C
4.2.11 Configuration of Optional Diagnostics Data
In addition to the Statistics, for each GEMCAN I/O Scanner module the user can optionally
configure three sections of additional Diagnostics Data:-
•
Node Data
GEMTEQ I/O Technical Manual (T2031En)
Rev.02 (10/10) Page 4-7
•
Input PDO Fault Data