Sequence number messages, Retrieve statistics message – Comtrol UP DeviceMaster User Guide User Manual
Page 61

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