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Sequence number messages, Retrieve statistics message – Comtrol UP DeviceMaster User Guide User Manual

Page 61

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DeviceMaster UP Modbus/TCP User Guide: 2000447 Rev. I

Chapter 2. Programming Interface - 61

Sequence Number Messages

2.4.5. Sequence Number Messages

PLC-5/SLC typed read and typed write messages can read and modify both receive and transmit produced
data sequence numbers. These are the same sequence numbers returned to the PLC in the Receive Data
Message
and sent to the DeviceMaster UP in the Transmit Data message. Access to these sequence numbers
are provided primarily for initialization purposes at the start of the PLC program when you may want to
initialize the sequence numbers on the PLC, DeviceMaster UP or both.

PLC-5/SLC typed read and write messages can also read and modify the consumed receive sequence
number(s). The consumed receive sequence number(s) are used in the Write-to-File-Synced communication
method.

2.4.6. Retrieve Statistics Message

The data returned from the Retrieve Statistics message is identical to the data returned for the Serial Port
Statistics
Object. The Retrieve Statistics message formats the data into 32-bit integers and returns data in an
array of s just like all data sent to a PLC-5 or SLC PLC. The first contains the least significant word and the
second contains the most significant word.

The following table displays the format of the Retrieve Statistics message.

The Retrieve Statistics messages have the following characteristics.

Index

Name

Data Type

Data Value(s)

Access Rule

1

Receive Byte Count

UDINT

0=default

Read only

2

Receive Packet Count

UDINT

0=default

Read only

3

Transmit Byte Count

UDINT

0=default

Read only

4

Transmit Packet Count

UDINT

0=default

Read only

5

Dropped Packet to PLC Count

UDINT

0=default

Read only

6

Parity Error Count

UDINT

0=default

Read only

7

Framing Error Count

UDINT

0=default

Read only

8

Overrun Error Count

UDINT

0=default

Read only

9

Received Consumed Sequence Error
Count

UDINT

0=default

Read only

10

Duplicate Transmit Sequence Number
errors

UDINT

0=default

Read only

11

Unexpected Transmit Sequence
Number errors

UDINT

0=default

Read only

12

Dropped Packet to Application Count

UDINT

0=default

Get

Retrieve Statistics Message Description

Receive Byte Count

This attribute counts the number of bytes received on the serial port.

Receive Packet Count

This attribute counts the number of packets received on the serial port.

Transmit Byte Count

This attribute counts the number of bytes transmitted on the serial port.

Transmit Packet Count

This attribute counts the number of packets transmitted on the serial port.

Dropped Packet to PLC Count

This attribute counts the number of dropped receive packets on the serial
port intended for the PLC due to:

No STX byte(s) found

No ETX byte(s) found

Time-outs

Too large of packet

Receive buffer queue overflows