A request was made to a device address that does not exist. For example, you tried to read register number 4000 when there are only 200 registers in the I/O device. Check the Variable Tags database to find the variable in error.

The server canceled the command while it was being processed by the driver. The driver may have taken too long to process the command. If a driver does not respond during the specified time limit, Citect SCADA cancels the command. The time limit is the product of the timeout period and the number of times to retry a command after each timeout. You can increase these values in the Timeout and Retry parameters for the protocol. also check the WatchTime parameter for the frequency with which the driver checks the link to the I/O device. Check also for communication errors.

A request was made that specified a data type not supported by the protocol. This error will not occur during normal operation. Restart the computer to reset every driver and hardware. If the problem persists, contact Technical Support for this product. If you have written your own protocol driver, this error is caused by a mismatch in the compiler specification and the driver's database.

A write request contains invalid data, for example you tried to write to a floating-point address with an invalid floating-point number. Check the Citect SCADA database.

The server sent a command that the driver did not recognize. This error will not occur during normal operation. Try re-booting the computer to reset drivers and hardware. If the problem persists, contact Technical Support of this product.

A problem exists with the communication channel, causing errors in the transmitted data. Inspect the setup for the communication channel hardware. For example, there may be a mismatch in parityA communications error-checking procedure. The number of 1's must be the same (even or odd) for each group of bits transmitted without error., baud rateThe number of times per second a signal changes in a communication channel. While the baud rate directly affects the speed of data transmission, the term is often erroneously used to describe the data transfer rate. The correct measure for the data rate is bits per second (bps)., stop bits, or data bits between the transmitter and receiver. Check that the setup of the I/O device and the field data in the Citect SCADA Ports and Boards forms are the same.

An I/O device is not responding to read or write requests. The driver sent a command to the I/O device and the I/O device did not respond within the timeout period. This is usually the first indication of loss of communications. Check that the I/O device is correctly connected to the server and is switched on. This error can also occur if the timeout period is too short. Try increasing the timeout period in the Timeout parameter for the protocol. You could also increase the delay time between receiving a response and sending the next command, by increasing the Delay parameter.

Citect SCADA has established communications with the I/O device; however, the I/O device has detected an error in the protocol. This error could be caused by a fault in the communications linkA connection between computers and peripheral devices, enabling data transfer. A communications link can be a network, a modem, or simply a cable., or an error in the ladder logic (in the I/O device).

Solution:

1. Check that the I/O device is operating correctly.

2. Check the communication cable is connected correctly (at both ends).

3. Use the Device Communications Wizard to check that the configuration of the I/O device (in particular, the Address and Special Options fields) matches the recommended settings and the settings on the I/O device.

4. If you are using serial communications, use the Device Communications Wizard to check that the configuration of the Port (in particular the Baud Rate, Data Bits, Stop Bits, and Parity) matches the recommended settings and the settings on the I/O device.

5. Display the hardware alarm page, and note the protocol error that is displayed.

6. Use the documentation that was supplied with your I/O device, network, and communication board to locate the error.

7. Check the ladder logic in the I/O device for errors.

8. Run the Setup Wizard.

9. Re-compile the project and start the Citect SCADA runtime.

A write operation was attempted to a location that is protected against unauthorized modification. Change the access rights to this location to permit a write operation.

A problem exists with either the communication channel, server, or I/O device hardware. Examine hardware components. The command or data request has not been processed. The server's operation may no longer operate normally.

The communication link between the server and the I/O device is functioning correctly, however the I/O device has some alert condition active, for example the I/O device is in program mode. Check that the I/O device is in the correct mode.

The I/O device is in off-line mode, preventing any external communication.

Solution:

1. Check that the I/O device is operating correctly.

2. Check the communication cable for breakage.

3. Check the communication cable is connected correctly (at both ends).

4. If you are using serial communications, check that the communication cable matches the diagram in the help system.

5. Use the Device Communications Wizard to check that the configuration of the I/O device (in particular, the Address and Special Options fields) matches the recommended settings and the settings on the I/O device.

6. If you are using serial communications, use the Device Communications Wizard to check that the configuration of the port (in particular the baud rate, data bits, stop bits, and parity) matches the recommended settings and the settings on the I/O device.

7. Run the Setup Wizard.

8. Check the Citect.ini file for the following:

[IOSERVER]

Server=1

Name=<name>

where:

<name> is the name of the server configured in the Citect SCADA project. (Use Custom Setup to check the server name.)

9. Re-compile the project and start the Citect SCADA runtime system.

Note : If you have standby I/O devices configured, this error will cause any standby I/O devices to become active. The command or data request current when the I/O device went off-line has not finished.

An internal software error has occurred in the driver. This error should not occur during normal operation. Try re-booting the computer to reset drivers and hardware. If the problem persists, contact Technical Support of this product.

An attempt has been made by an unauthorized user to access information. Check the user's access rights.

The server is out of memory and cannot continue execution. Minimize buffer and queue allocation or expand memory in the server computer. The command or data request has not been processed.

There are no communication buffers available to be allocated, or the computer is out of memory. The performance of the server may be reduced, however it can continue to run. Increase the memory.

This error may occasionally occur in periods of high transient loading, with no ill effects. If this error occurs frequently, increase the number of communication buffers.

Too many commands have been sent to the driver.

The server is not receiving any response from the driver. This error should not occur during normal operation. Try re-booting the computer to reset the drivers and hardware. If the problem persists, contact Technical Support of this product.

Each driver can only support several communication channels. You have exceeded the limit. This error may occur if you abnormally terminate from the server and then restart it. Try re-booting the computer to reset drivers and hardware. If the problem persists, contact Technical Support of this product. The command or data request has not finished.

A communication channel is currently off-line, disabling communication. Either the server cannot initialize the communication channel or the channel went off-line while running. Check the channel hardware for errors. When this error occurs, I/O devices connected to this channel are considered off-line, and standby I/O devices become active. The command or data request has not finished.

The server has attempted to communicate with a channel that is not open. Try re-booting the computer to reset drivers and hardware. If the problem persists, contact Technical Support for this product.. The command or data request has not finished.

The server is attempting to communicate with a channel that has not been initialized. This error should not occur during normal operation. Try re-booting the computer to reset drivers and hardware. If the problem persists, contact Technical support for this product. The command or data request has not finished.

A channel has too many I/O devices attached to it. This error should not occur during normal operation. The command or data request has not finished. Try re-booting the computer to reset drivers and hardware. If the problem persists, contact Contact Technical Support for this product..

The data requested is still being processed and will be returned in due course. This error only occurs with drivers that need to establish complex communication to retrieve data from the I/O device. Ignore this alert.

The server tried to cancel a command, but the driver could not find the command. This error should not occur during normal operation. Try re-booting the computer to reset drivers and hardware. If the problem persists, contact Contact Technical Support for this product..

Communication has been switched from the primary to the standby I/O device(s). The server returns this message when a "hot" changeover has occurred. Rectify the error in the primary I/O device(s).

A response was longer than the response buffer. If this error occurs on serial communication drivers, garbled characters may be received. Check the communication link and the baud rate of the driver.

There is a configuration error, for example invalid special options have been set.

There is an error in a standby I/O device. Rectify error in the standby I/O device.

One or more requests sent to the I/O Server have not finished in the timeout period. Either the I/O Server is off line or the I/O Server is taking too long to finish the requests. Check the PLC communication link, PLC timeouts, PLC retries, and network communication. This error can occur even if you have no network, i.e. if the I/O Server is the same computer as the Control ClientThe interface between the runtime system and an operator. If you are using Citect SCADA on a network, all computers (on the network) are control clients.. If the error persists, increase the [LAN] TimeOut parameter. The default timeout is 8000 milliseconds.

The remote I/O device is not connected.

An invalid argument has been passed to a Cicode function. This is a general error message and is generated when arguments passed to a function are out of range or are invalid. Check the value of arguments being passed to the function. If arguments are input directly from the operator, check that the correct arguments are being passed to the function.

The specified Citect SCADA server cannot be found. Either the server is not running or there is some communication problem with the network. Check that the network is set up correctly, and you are using the same Server Name on both the client and server.

There is no server of the necessary type configured on the server.

An RDB file contains records with the wrong size.

Unable to start a reload using the ServerReload Cicode function as a reload is already in progress for the specified server.

An RDB file was compiled using an incompatible version of the software.

The timestamp of the Cicode library in memory is different from the timestamp of the Cicode library on disk. The Cicode libraries are potentially different.

Cicode call that triggers an RPC remote call is interrupted before the expected result is returned.

A category number is out of its valid range (from 0 to 16376 inclusively).

A record was deleted during a reload of ART server.

A trend record's archive properties have changed during start-up or reload.

A category priority is out of its valid range (from 0 to 256 inclusively).