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Each entry can be configured for one of two types of initiating a transaction: Polled and
Triggered. Polled type entries initiate a transaction with the remote device on every
transaction scan. Triggered type entries only initiate a transaction when a corresponding local
(OCS) binary trigger register is
set
. Once a triggered type transaction completes, the protocol
device driver
resets
the local (OCS) binary register to indicate completion. See
section for more details on Polled and Triggered entries.
These basic types are also subdivided into Read or Write operations. For polled operations, a
Read operation only reads from a remote device. Likewise, a Read/Write operation
continuously reads from the remote device unless the target OCS register value changes from
one ladder scan to another. In this case, the new OCS value is written to the target device. For
triggered operations, only a Read or Write action is available.
When downloaded to the OCS, the Scan List is scanned sequentially to generate data
transactions with the remote device. This transaction scanning can be on a continual basis
(automatic) or controlled from ladder logic (manual) once a complex connection is
programmatically created (i.e., dialup modem). The specific transaction-scanning mode is
selected from the Network Config menu.
The following Horner Automation websites offer OCS Protocol Software Downloads.
North America
http://hornerautomation.com/support-files/
Europe
http://horner-apg.com/en/products/software/ocs-protocols.aspx
Please refer to the Cscape Help file for more information on Downloadable Protocols
Configuration. After opening the Cscape Help file, select Contents
→
Networking and
Communications
→
Protocol Configuration.
