ProSoft Technology MVI71-DNP - Manual (Page 132)

MVI71-DNP ♦ PLC Platform Reference
DNP 3.0 Master/Slave Communication Module
Page 132 of 172 ProSoft Technology, Inc.
August 23, 2007
5.9 Error Status Table
The program maintains an error/status table. This table of data is available to the
PLC processor automatically through block 100. Ladder logic should be
programmed to accept this block of data and place it in the module's controller
tag. You can use the error/status data to determine the "health" of the module.
The data in the block is structured as shown in the following table:
Word Block
Offset Variable Name Description
0 2 Current DNP Slave Port
status
This value represents the current value of the
error code for the port. This value will only be valid
if the port is configured as a slave. The possible
values are described in the application
documentation.
1 3 DNP Slave Port last
transmitted error code
This value represents the last error code
transmitted to the master by this slave port.
2 4 DNP Slave Port total
number of message frames
received by slave
This value represents the total number of
message frames that have matched this slaves
address on this port. This count includes message
frames which the slave may or may not be able to
parse and respond.
3 5 DNP Slave Port total
number of response
message frames sent from
slave
This value represents the number of good (non-
error) responses that the slave has sent to the
master on this port. The presumption is that if the
slave is responding, the message was good.
Note: This is a frame count.
4 6 DNP Slave Port total
number of message frames
seen by slave
This value represents the total number of
message frames received by the slave, regardless
of the slave address.
5 7 DNP Slave synchronization
error count (Physical Layer
Error)
This value counts the number of times a sync
error occurs. The error occurs when extra bytes
are received before the start bytes (0x05 and
0x64) are received.
6 8 DNP Slave overrun error
count (Physical Layer Error)
This value counts the number of times the overrun
error occurs. This error occurs when the mainline
Data Link Layer routine cannot read the data
received on the communication port before it is
overwritten.
7 9 DNP Slave length error
count (Physical Layer Error)
This value counts the number of times an invalid
length byte is received. If the length of the
message does not match the length value in the
message, this error occurs.
8 10 DNP Slave bad CRC error
(Data Link Layer Error)
This value counts the number of times a bad CRC
value is received in a message.
9 11 DNP Slave user data
overflow error (Transport
Layer Error)
This value counts the number of times the
application layer receives a message fragment
buffer which is too small.
10 12 DNP Slave sequence error
(Transport Layer Error)
This value counts the number of times the
sequence numbers of multi-frame request
fragments do not increment correctly.