G&L MMC-A2, Hardware Manual

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MMC DeviceNet
TM
Option Module
G & L Motion Control Inc. MMC Hardware Manual 133
7.4 Theory of Operation
The DeviceNet scanner module provides a memory image of the nodes
(slaves) connected to a DeviceNet network. It is this memory image that is
controlled by your LDO created in PiCPro. The module’s on-board processor
continually transfers data between this memory image and the actual
DeviceNet nodes.
Communication between the DeviceNet module and the nodes can be set at
125 Kbaud, 250 Kbaud, or 500 Kbaud. The baud rate, the relationship
between the memory image and specific data in each node, and other
parameters are established with configuration software run in an external PC.
This configuration software generates two files. One file is downloaded to
the DeviceNet module through its RS232 serial port. The other file is used by
PiCPro to establish the relationship between the memory image and the
declared variables in the LDO. To ensure that a given location in the memory
image is connected to a variable in the LDO and to the corresponding data in
the DeviceNet node, the same tag name or label must be used.
For example, when running the configuration software, PROX_SW1 could
be used as the name for the boolean bit representing a DeviceNet proximity
switch’s logic state. The name PROX_SW1 must also be used for the
corresponding variable in your LDO.
NOTE
The G&L Motion Control DeviceNet configuration software (G&L
Motion Control Part No. M.1017.4267) is required to configure the
DeviceNet scanner (within the DeviceNet module) for the devices on
the associated network.
NOTE
Additional information about DeviceNet can be obtained from
www.odva.org.