Horner APG XL4 OCS HE-ETN300 - Manual (Page 41)

SUP0740-07 CH.6
11/30/2009 Page 41 of 98 # 958
6.7.2 EGD Consumed Exchange Status Words
The Status Word for an EGD Consumed Exchange can take on the following values:
0
IDLE - No new status event has occurred. The Ethernet Module initializes all Status
Words to 0, only at power-up and each time the OCS enters RUN mode. Subsequently,
the OCS application ladder program can write the value 0 to the Status Word, as an aid
in knowing when Ethernet Global Data consumption occurs (see Status Words 1 and 7).
1
OK - Data Consumed. New EGD network data has been received as expected (before
the configured Update Timeout expired). A transition to 1 (or to 7) indicates consumption
of data occurred since the last OCS ladder scan.
2
NO LINK - The Ethernet link was down when EGD data consumption was expected. This
will occur, for example, if the Ethernet cable is unplugged from the OCS.
3 NO SYNC - SNTP Error. The Ethernet Interface in the device producing the exchange is
configured for network time synchronization (Network Time Sync parameter is set to
SNTP), but is not synchronized to an SNTP server. Therefore, the timestamp associated
with this data is not synchronized to the network. Note: This error condition is considered
the least important of all the error codes in this section. If another error condition exists,
its status code will appear in the Status Word.
6 OVERDUE - Data Refresh Error. The Update Timeout has expired without receiving the
expected data. Some possible causes for this error are: (1) the Producer has stopped
producing the data, (2) the Consumed Exchange’s configured Producer IP Address
and/or Group ID do not exactly match those of the corresponding Produced Exchange,
(3) or the Consumed Exchange’s configured Update Timeout is too short (it should
normally be twice the producer’s Production Period, plus 10 milliseconds).
7
TARDY - Data Consumed Late. New EGD network data has been received, but it is later
than expected (after the configured Update Timeout expired). A transition to 7 (or to 1)
indicates consumption of data occurred since the last OCS ladder scan. The most
probable cause for this error is that the Consumed Exchange’s configured Update
Timeout is too short (it should normally be twice the producer’s Production Period, plus
10 milliseconds).
6.8 EGD Example 1
Figure 6.6 shows a simple example, in which Node 1 uses Exchange 1 to transmit 10 words of
data to Node 2 every 100 mS, and Node 2 uses Exchange 2 to transmit 5 words of data to Node
1 every 200 mS.
Figure 6.6– EGD Example 1 Exchange Interaction
Node 1
IP Address
192.168.0.1
Node 2
IP Address
192.168.0.2
Exchange 1: Produced by Node 1; Consumed by Node 2;
192.168.0.1 sends 10 words of data every 100 mS to 192.168.0.2
Exchange 2: Produced by Node 2; Consumed by Node 1;
192.168.0.2 sends 5 words of data every 200 mS to 192.168.0.1