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RUGGEDCOM ROS
User Guide
Section 5.4.2.3
Turnaround Delay
The Modbus protocol uses the concept of a turnaround delay in conjunction with broadcast messages. When the
host sends a broadcast message (that does not invoke an RTU response), it waits for a turnaround delay time. This
delay makes sure the RTU has enough time to process the broadcast message before it receives the next poll.
When polling is performed over TCP, network delays may cause the broadcast and next poll to arrive at the remote
server at the same time. Configuring a turnaround delay at the server will enforce a minimum separation time
between each message transmitted via the serial port.
Note that turnaround delays do not need to be configured at the host computer side and may be disabled there.
Section 5.4.3
DNP, Microlok, TIN and WIN Concepts
The following section describes some of the concepts related to Distributed Network Protocol (DNP), Microlok, TIN
and Wireless Intelligent Network (WIN) as they relate to the implementation of serial protocols in ROS.
CONTENTS
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Section 5.4.3.1, "DNP, Microlok, TIN and WIN Applications"
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Section 5.4.3.2, "The Concept of Links"
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Section 5.4.3.3, "Address Learning for TIN"
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Section 5.4.3.4, "Address Learning for DNP"
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Section 5.4.3.5, "Broadcast Messages"
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Section 5.4.3.6, "Transport Protocols"
Section 5.4.3.1
DNP, Microlok, TIN and WIN Applications
RMC30 supports a variety of protocols that specify source and destination addresses. A destination address
specifies which device should process the data, and the source address specifies which device sent the message.
Having both destination and source addresses satisfies at least one requirement for peer-to-peer communication
because the receiver knows where to direct responses. Each device supporting one of these protocols must have a
unique address within the collection of devices sending and receiving messages to and from each other.
Turnaround Delay
Chapter 5
Setup and Configuration
135
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