ProSoft Technology MVI71-GSC - Manual (Page 60)

MVI71-GSC ♦ PLC Platform Reference
Generic Serial Communication Module
Page 60 of 82 ProSoft Technology, Inc.
January 31, 2008
Read-Only Devices
Read-Only devices are those that only receive data from the module. An
example of this type of device is a printer. The printer will generate output or be
controlled based on the data it receives on its communication port. Ladder logic
is used to construct the write blocks to be sent to the module. When the module
receives a new write block containing data, it will transmit the data out the port.
The Block Sequence Number used in the write block should be the one received
on the last read block. The data flow diagram for a read-only device is shown
below: