User`s guide

MBX Driver Help
Cyberlogic Technologies Inc. - 10 -
the controller. Such a routing might be: 15.37.0.0.0. This will route the message to the
bridge at node address 15 of the local network, and from there it will go to the controller
at node 37 on the remote network. As before, the zeros indicate that there is no further
routing.
By using all five routing array bytes, it is possible to route the message through up to
four bridges before it reaches its final destination. A routing array of 5.42.17.3.29 will
route the message to the bridge at node 5 of the local network, then from there to the
bridge at node 42 of the remote network, then to the bridge at node 17 of the next
network, then to the bridge at node 3 of the following network and finally to the
programmable controller at node 29 of the last network in the chain.
Routing to Network Adapters
When the message is sent to a network adapter such as a PCI-85, the second-last non-
zero byte is the node address of the adapter, and the last non-zero byte specifies a slave
path (DS or PS) internal to the adapter. As an example, a routing array of 5.8.0.0.0
would be used to send the message to a network adapter at node address 5 of the local
network, and instruct it to use slave path 8 within the adapter.
Solicited (Master Path) Communications
Each interface adapter, such as a PCI-85, allows a maximum of eight simultaneous data
and program solicited transactions. These transactions are called Data Master (DM) and
Program Master (PM) path transactions.
The MBX Driver overcomes these physical limitations, allowing up to 65,535 simultaneous
Data Master path transactions. The eight physical DM paths are multiplexed by the driver
among all logical DM paths currently opened by all applications. This technique is highly
efficient and greatly improves communication capabilities of applications.
This change does not affect any existing applications. New applications take advantage
of this capability by opening a large number of DM paths for better performance and
simpler message handling. The PM paths are still limited to a maximum of eight.
Unsolicited (Slave Path) Communications
Each interface adapter card allows eight simultaneous data and program unsolicited
transactions. These transactions are called Data Slave (DS) and Program Slave (PS) path
transactions.
Only one user application can receive messages over an individual DS or PS path. While a
DS or PS path is in use by an application, it is the application’s responsibility to respond
to any received command message.
If command messages are received over unused DS or PS paths while the driver is in the
on-line mode, the driver automatically sends negative response messages to the
message originator. When the driver is off-line, the negative response messages are
normally sent by the adapter card.