Publication 1747-RM001G-EN-P - November 2008
SLC Communication Channels 13-17
General Solicit rotations 30 Number of times a complete solicit successor of all stations not on the link is
completed. A solicit successor occurs during a token pass around the link. Here a station
that is currently not on the link is solicited to see if it has been added to the link. During
each token pass, a different station number is solicited; solicitation occurs sequentially.
A station can only join the link when it is solicited into it.
Data Sent
with
Acknowled-
gement
(SDA)
Received 15 Number of error-free SDA messages that the station received.
Received with error 16 Number of invalid SDA messages that the station received. Some causes are:
• bad CRC.
• the message has an invalid source address.
• the message has an unrecognizable control byte.
• the transmission was aborted.
This counter indicates noise; increase the cable’s shielding from noise.
Received
retransmissions
17 Number of times the sending station re-transmitted an SDA message, which was
ACKed or NAKed. If node sends a message but does not receive an ACK or a NAK
response, the node will re-transmit the message. If a node retransmitted a message
because the acknowledge response to the first message was lost, the node receiving
the message detects the retransmission and sends an acknowledge response. But the
receiving node discards the duplicate message. High counts of this counter indicates
noise or cable problems; check that the cable is secure and properly shielded from
noise.
Received but full 18 Number of SDA messages that the station could not receive because of lack of memory.
Received SAP off 19 Number of SDA messages that the station received but could not process because its
service access point (SAP) was off.
This counter should always be 0.
Transmit confirm 20 Number of SDA messages successfully sent to and acknowledged by the addressed
station.
Transmit NAK misc. 21 Number of incoming SDA messages that were NAKed due to reasons other than the
NAKed full and NAKed inactive counters (for example, a NAK due to a bad CRC).
Transmit time-out 22 Number of SDA messages that were sent but not ACKed or NAKed by the receiving
station. This counter increments even if the message does get through during a retry
and if the receiving station is unable to communicate. This counter indicates a noise or a
cabling problem (the receiving station is not seeing the messages).
Transmit not ACKed 23 Number of SDA messages that were sent but were not ACKed by the receiving station.
The following could have occurred.
• Message could have been NAKed
• An invalid ACK was returned
• Nothing was returned
This counter can indicate:
• a noise or a cabling problem.
• the receiving station has been removed from the link.
• the receiving station cannot communicate.
Table 13.5 SLC 5/04 Channel 1 DH+ Channel Status (Continued)
Status field Word Displays the
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