The messages in the following sections are logged to the BASEstar Classic history file by the DAS for AB Data Highway Protocol. These messages are logged to provide more detailed diagnostic information than what is supplied by the returned status values.

Messages logged to the history file for DAS for AB Data Highway Protocol use event class 21 and event type 25.

To view all messages logged by this DAS use the following syntax:

$ BSTAR BSTAR> SHOW HISTORY/EVENT=21.25.*

A.1 NI Logged Messages

The following messages are logged by the Network Interface (NI).

Hangup occurred on the line.
Explanation: Informational. If the port is a LAT port, then either the network connection to the terminal server has been broken or the serial line connection to the PLC has been disconnected. If the port is a TT port, then the serial connection to the PLC has been disconnected.
User Action: If the cause of the hangup was a network disconnection, then determine the cause of the network disconnection (could be physical problems with the network or the terminal server was powered down) and correct the problem. If the cause of the hangup was the port, then check for broken or missing cables and correct any problems found.

Station is being removed.
Explanation: Informational. This message logs the identity of a station being disconnected due to a hangup on the line.
User Action: None.

Did not find DLE ETX within buffer limit.
Explanation: Error. A message was received on the data highway, but no DLE ETX pair was found before the end of the buffer. Normally, a data highway message is framed by a DLE STX msg DLE ETX pair. In this case the DLE ETX is missing. The cause for this occurrance could be dropped or garbled characters on the line. If the problem persists, there is likely a problem with the cable that connects the data highway to the host.
User Action: Check for frayed wires, improper shielding, improper cable length or routing of the cable near high noise generating equipment such as welders. If using a terminal server, check the terminal server counters for errors such as overruns or parity errors.

Unexpected ETX received. Message discarded.
Explanation: Error. An ETX was received when expecting an ACK, NAK or ENQ character. An ETX should not be received at this point, so the message is discarded. The message that was received is also logged to the history file. The likely cause for this error is either a noisy cable that connects the data highway to the host or, if using a terminal server, an overloaded or faulty network that is causing unusual delays in transmitting and receiving data.
User Action: Check for frayed wires, improper shielding, improper cable length or routing of the cable near high noise generating equipment such as welders. If using a terminal server, check the terminal server counters for errors such as overruns or parity errors.

Possible DLE ACK or DLE NAK embedded in packet - !UB.
Explanation: Error. There is either a DLE ACK or DLE NAK sequence embedded in the packet received from the device. (The actual characrter (ACK or NAK) is logged.) Since the DAS does not support embedded responses other errors are likely to be generated.
User Action: Check the communications card being used to communicate to the data highway and ensure that the embedded responses switch is set to OFF.

Unmatched trans number received for station, tns # = !UW.
Explanation: Error. A response message was received from a PLC and the transaction number in the message does not match any current outstanding transactions. The transaction may have already timed out or this transaction may be a duplicate of one already received. If the transaction has already timed out, then messages are being received too late due either to data highway or, if using a terminal server, to ethernet network delays.
User Action: First determine the cause of the error. If the error is due to a transaction timing out, then the timed out transaction should also have been logged. In this case, determine the cause of the delays in the network, and correct the problem.

Discarded unsolicited message. Unsolicited read queue exhausted.
Explanation: Error. The DAS maintains a queue of buffers to receive unsolicited messages. The size of this queue defaults to a value of "5", but can be increased (or decreased) by creating and setting the parameter ILAN$ABX_UNSOL_QUEUE_SIZE. The name of the parameter is different for each PLC family. This error indicates that all buffers in the queue have been used and no more are available, so the incoming transaction has been discarded and is lost. The cause of the error is either too small a queue size or messages are being received faster than they can be processed.
User Action: Either increase the size of the queue, decrease the number of messages being transmitted, or increase the processing speed of the host.

Discarded unsolicited message. Station not configured.
Explanation: Error. An unsolicited message was received from a PLC station that has not been configured in BASEstar software. This message can also occur for a station that has been configured during startup of the system if a message is received after the line has been configured but before all the devices on the line have reached the "connected" state.
User Action: Configure a device for the station sending the messages. If the message occurs during startup only, then no action needs to be taken.

Data highway error - status code = x!XB.
Explanation: Error. An error has been returned by data highway. The status code returned is logged in the message.
User Action: Look up the error in Allen-Bradley Data Highway/Data Highway Plus Protocol and Command Set and take action based on the error found. Also, examine the log file for any extended status codes that may be logged as well.

Data highway error - extended status code = x!XB.
Explanation: Error. An error has been returned by data highway. The extended status code returned is logged in the message.
User Action: Look up the error in Allen-Bradley Data Highway/Data Highway Plus Protocol and Command Set and take action based on the error found.

NAK sent. BCC did not match, expected x!XB, received x!XB.
Explanation: Error. The checksum calculated by the DAS and the checksum received in the message did not match. The DAS responded to the message by sending a "NAK". This message is probably caused by a noisy line that is either dropping or inserting characters into the message.
User Action: Check for frayed wires, improper shielding, improper cable length or routing of the cable near high noise generating equipment such as welders. If using a terminal server, check the terminal server counters for errors such as overruns or parity errors.

Bad QIO read status,
Explanation: Error. An error occurred when reading a message from the line. The status code returned from the OpenVMS system service QIO call is logged along with this message.
User Action: Examine the error status and take action based on the error found.

Bad QIO write status,
Explanation: Error. An error occurred when writing a message to the line. The status code returned from the OpenVMS system service QIO call is logged along with this message.
User Action: Examine the error status and take action based on the error found.

Unexpected ACK received. No request pending.
Explanation: Error. An ACK was received when there is no write currently pending. The most likely cause for this error is that the write has already timed out. The timeout can be caused by a busy data highway or a loaded network, if connected via a terminal server.
User Action: The default timeout for the DAS is 3 seconds. The timeout value can be increased by modifying the /TIMEOUT parameter on the path definition. Alternatively, the response time can be shortened by decreasing the load on either the data highway network or the ethernet network, if connected via a terminal server.

Timed out waiting for transaction = !UW.
Explanation: Error. A pending transaction timed out. The timeout time is 3 times the read timeout set in the /TIMEOUT parameter on the path definition. (If the /TIMEOUT parameter is not set, then the timeout defaults to 3 seconds, and the transaction timeout is 9 seconds.) If the transaction is arriving late another message is logged stating that no matching transaction number is found. In this case, it is likely that either the communication card is having trouble processing all the transactions on the data highway or there are significant errors or retries that are slowing down the effective transaction rate.
User Action: The transaction timeout can be indirectly modified by increasing the /TIMEOUT parameter on the path definition. If the transaction is arriving late, then determine where the bottleneck in communications is occurring (either the data highway communications card, the ethernet network or the host processor) and take actions to reduce the load.

Unexpected NAK received. No request pending.
Explanation: Error. A NAK was received when there is no write currently pending. The most likely cause for this error is that the write has already timed out. The timeout can be caused by a busy data highway or a loaded network, if connected via a terminal server.
User Action: The default timeout for the DAS is 3 seconds. The timeout value can be increased by modifying the /TIMEOUT parameter on the path definition. Alternatively, the response time can be shortened by decreasing the load on either the data highway network or the ethernet network, if connected via a terminal server.

Discarded garbage data on line - message lost.
Explanation: Error. An unexpected protocol control sequence was received, so the message is discarded. The message that was received is also logged to the history file. The likely cause for this error is either a noisy cable that connects the data highway to the host or, if using a terminal server, an overloaded or faulty network that is causing unusual delays in transmitting and receiving data.
User Action: Check for frayed wires, improper shielding, improper cable length or routing of the cable near high noise generating equipment such as welders. If using a terminal server, check the terminal server counters for errors such as overruns or parity errors.

Discarded unsolicited message. Unsupported command = x!XB sent by PLC.
Explanation: Error. An unsolicited message was received from a PLC, but the command in the message is one that is not supported by the DAS. The command code that is being sent by the PLC is logged in the message. The DAS only supports command codes for PLC-2 protected and unprotected writes.
User Action: Reprogram the PLC to send one of the two command codes supported by the DAS.

Discarded unsolicited message. Unsupported function = x!XB sent by PLC.
Explanation: Error. An unsolicited message was received from a PLC, but the function in the message is one that is not supported by the DAS. The function code that is being sent by the PLC is logged in the message. The DAS only supports command codes for PLC-2 protected and unprotected writes.
User Action: Reprogram the PLC to send one of the two command codes supported by the DAS.

No license is active for this software product.
Explanation: Error. The DAS could not find a license for the product.
User Action: Register and load a valid license for this DAS.