Publication 1756-UM514B-EN-P - February 2003
B-4 PCCC Commands Supported by the Data Highway Plus Module
Read DH+ Diagnostic Counters
Diagnostic counters are bytes of information stored in RAM in you
1756-DHRIO module. The counters occupy a block of the module’s
internal scratch RAM. Your module’s counters wrap around to zero
when they overflow.
Counters are used to record events that can be used in debugging and
long-term reliability analysis. You must issue a diagnostic read to
check the information in your module’s counters.
CMD = 06h, FNC = 01
The definition of the data returned is:
Table B.2
DH+ Diagnostic Counters
Byte Description
0 Received ACK/NAK with bad CRC
1 Timeout expired with no ACK received
2 Transmit retries exhausted
3 Received NAK (illegal protocol operation)
4 Received NAK (bad LSAP)
5 Received NAK (no memory)
6 Received ACK/NAK too short
7 Received ACK/NAK too long
8 Received something other than ACK/NAK
9 Token pass timeout
10 Token pass retries exhausted
11 Claim token sequence entered
12 Token claimed
13 Received frame with bad CRC
14 Transmitted NAK (illegal protocol operation)
15 Transmitted NAK (bad LSAP)
16 Transmitted NAK (no memory)
17 Received frame too short
18 Received frame too long
19 Received retransmission of a frame
20 Received frame aborted
21 Message successfully sent (low byte)
22 Message successfully sent (high byte)
To Next Page
Loading...
