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Publication S130E
Issue 1.0
Pakscan IIS Technical Manual
8.4.2 Port Diagnostic Displays
These screens give detailed diagnostic information for the serial links. The
top half
displays counts of various
message types:
msg
- count of messages received with valid address
err
- count of errors, e.g. overrun errors, parity errors, Baud rate errors
xcpt
- count of Modbus exception responses generated
crc
- count of messages received with incorrect CRC's
The
bottom half
shows details of the last message received, (the address and data in decimal format):
Mod
- the Modbus address of the last request
func
- the Modbus function code of the last request
addr
- the discrete bit or register number in the last request
data
- the data field of the last request, typically the number of points or registers
Some familiarity with the protocol is needed to make use of this display. Its purpose is help in commissioning
a serial communications link to a Host computer by getting the master station to show what it thought it
received. If you then refer to the protocol specification you can check whether those messages are correct. The
display is normally 'frozen' and is only updated when a key is pressed (any key except the Menu key). This
gives you time to take note of the numbers. Most Host systems are set up to send out a short sequence of
requests for data, and by pressing a key a few times you should be able to capture all the messages. The
"Clear" key resets the counters on the top half of the screen.
Commands available:
- Zeros the message and error counts
- Or any other key except Clear or Menu updates display with the last
message
- Return to previous menu
Port number
1 msg err xcpt crc
2 msg err xcpt crc
Message counts
1 0 0 0
1 0 0 0
Mod func addr data
Mod func addr data
Last message details
1 2 1920 48
2 2 1920 48
MENU
CLEAR
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