User`s guide

MBX Driver Help
Cyberlogic Technologies Inc. - 11 -
When the driver goes off-line, it will normally place the adapter card in the off-line state.
However, if the system crashes, the driver will not have an opportunity to properly
transition the adapter card’s state. In such a case, the adapter card would never respond
to the command messages, resulting in lengthy timeouts on the Modbus Plus network.
To avoid this, adapter cards that support Peer Cop have a diagnostic watchdog timer that
automatically places the adapter card in the off-line state if the host system is inactive
for a pre-configured period.
Caution!
For compatibility with older adapter cards, the watchdog timer is disabled by default.
We strongly recommend that you enable the timer and set it to 2.5 sec for adapter
cards that support it.
Global Data Communication
Each Modbus Plus node can transmit up to 32 words of global data to the rest of the
nodes on the local network. The global data is transmitted as part of each node’s token
passing message. As a result, in a single token rotation, all Modbus Plus nodes get an
opportunity to transmit their global data. This type of communication is very fast and it is
commonly used for transferring state information between controller nodes.
Peer Cop Communications
Peer Cop communications are similar to the global data communications. Like the global
data, the Peer Cop data is transmitted as part of each node’s token passing message. As
a result, in a single token rotation, all Modbus Plus nodes get an opportunity to transmit
their Peer Cop data. This type of communication is very fast and it is commonly used for
transferring state information between controller nodes and communicating with
distributed I/O nodes on the Modbus Plus network.
The MBX Driver automatically detects whether the adapter card is capable of supporting
Peer Cop communications. As a result, older and newer versions of adapter cards can be
intermixed in the same system. In addition, as more adapter cards are upgraded to
support Peer Cop, the MBX Driver will support these cards as well.
Summary of Peer Cop Communications
To fully utilize the multi-tasking nature of the Windows environment, Peer Cop support in
the MBX Driver exhibits the following characteristics:
 Concurrent Peer Cop functionality from multiple applications using a single
interface adapter card, such as a PCI-85.
 Any application can read Peer Cop data from any node on the network.
However, only one application is allowed to write specific outputs to a given
node.
 Applications can acquire and release access to Peer Cop specific outputs.
Once control over specific outputs at a given node is released by the