
Getting Started
2–3
Getting Started
The network is controlled by a master station that issues network commands to
individual slave stations (you cannot “broadcast” a message to all slaves). The
commands may be used to download data to the slave stations, or upload data from
the slave stations. The slave stations only respond to requests from the master
station and cannot initiate communications.
Issues Network Commands
to transfer data
Read V1400 from slave 1.....
Write X0–X15 to slave 3.....
Responds to Network Commands
Slave 1 Slave 2 Slave 3 Slave 4
Master
DirectNET uses the DirectNET communications protocol, but you don’t have to
understand the protocol to build the most common network configurations. A
description of the DirectNET protocol is included in Chapter 6 – DirectNET
Communication Programs.
Maximum Number of Slaves
90 per master (RS422 Amplifier
required for over 16 stations)
Configurations Point-to-point, multi-drop
Interface Type Serial RS232C / RS422
Half-duplex, Asynchronous operation
Transmission Rate 300 to 38.4K baud
Transmission Distance 3300 Feet (1000 meters)
Protocol DirectNET
How Does it Work?
Network Protocol
Network
Specifications
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