Communication driver-specific system item
- Last UpdatedAug 29, 2024
- 5 minute read
The system items described in this section refers to specific information regarding the Communication Driver, OI Server Manager, and the controllers.
The following generic system items are supported for all Allen-Bradley controllers, unless otherwise noted.
|
System Item Name |
Type/ Access Rights |
Description |
Values |
|---|---|---|---|
|
$SYS$DeviceStatus |
String/Read |
Status of the processor. |
RANGE: |
|
$SYS$Mode |
String/Read |
Current mode of the processor. |
RANGE: |
|
$SYS$PLCType |
String/Read |
Name of the process type. |
Descriptive text for the process type. |
|
$SYS$ProcessorName |
String/Read |
Name of the program running in the processor. |
Descriptive text for the corresponding processor name. |
|
$SYS$Revision |
String/Read |
Firmware of the processor. |
Descriptive text for the firmware revision. |
|
$SYS$UpdateTagInfo |
Boolean/ |
Force update of the whole controller tag database. The OI Server returns WriteComplete for $SYS$UpdateTagInfo when poked. The transaction will be completed with no timeout. Note: The value in $SYS$Update TagInfo will return to "0" from "1" after the process is finished. Note: The OI Server will implement manual and automated updates of the ControlLogix tag database in the event that you add or delete items by direct controller programming. Warning! Updating a tag database online consumes resources. During the updating process, the Communication Driver may be held up from updating the client application. |
RANGE: |
The following tag-database-specific system items are supported for all Allen-Bradley controllers, unless otherwise noted.
|
System Item Name |
Type/ Access Rights |
Description |
Values |
|---|---|---|---|
|
$SYS$BrowseTags |
Boolean/ ReadWrite |
Indicates whether the controller tags are browsable from OPC client. If a TRUE value is written to this item, the controller tags will become browsable, provided that the tag database is ready at the time. If a FALSE value is written to this item, all controller tags will not be browsable. |
RANGE: True or false |
|
$SYS$TagDBStatus |
String/ Read-Only |
Indicates the status of the tag database as follows: |
|
|
Uninitialized – The tag database is uninitialized, typically in a start state. |
Uninitialized |
||
|
Uploading – The tag database is being uploaded from the controller |
Uploading |
||
|
Uploaded – The tag database has been completely uploaded from the controller. |
Uploaded |
||
|
Error – The tag database is not uploaded because of errors encountered during the upload |
Error |
||
|
$SYS$TagDBVersion |
String/ Read-Only |
Indicates the version of the Tag database. String format: MajorVersion. MinorVersion If version information cannot be acquired (for example, due to a bad PLC connection) the value initially displays "Uninitialized" as a string. |
RANGE: Major version: 0...65535 (no padding) Minor version: 0...999 (no padding) |
|
$SYS$UpdateTagInfo |
Boolean/ ReadWrite |
Forces update of the controller tag database upon adding the next item for advise or poking any value to an existing item (On or Off). |
RANGE: True or false |
The following Logix5000 system items are supported for ControlLogix, CompactLogix, and FlexLogix processors, unless otherwise noted.
|
System Item Name |
Type/ Access Rights |
Description |
Values |
|---|---|---|---|
|
$SYS$DeviceSecurity |
Boolean/ Read-Only |
Status of controller security |
RANGE: |
|
$SYS$Optimization |
Boolean/ |
Indicates the status of ControlLogix message optimization in handle mode as enabled with the ControlLogix Optimization check box under the Logix5000 node editor in OI Server Manager (True or False). If: FALSE - no message optimization will be used. TRUE - either the ‘Optimized for read’ option or the ‘Optimized for startup’ is being used. |
RANGE: |
|
$SYS$UDTOptimization |
Boolean/ |
Indicates the status of the ControlLogix user-defined data type optimization enabled with the User Defined Data Type Optimization check box under the Logix5000 node editor in the OI Server Manager (On or Off). |
RANGE: |
|
$SYS$FreeMem |
DWord/ |
Returns the current unused memory, in number of bytes, in the Logix processor (I/O + data table + general). This item is not supported on ControlLogix L8x controllers. For L8x controllers, quality will be 0x07 (CONFIG_ERROR and LIMIT_CONSTANT). |
RANGE: |
|
$SYS$FreeMemDT |
DWord/ |
Returns the unused data table memory in number of bytes. This item is not applicable to 1756-L1, and is not supported on ControlLogix L8x controllers. For L8x controllers, quality will be 0x07 (CONFIG_ERROR and LIMIT_CONSTANT). |
RANGE: |
|
$SYS$FreeMemGM |
DWord/ |
Returns the total available general memory in number of bytes. This item is applicable to 1756-L55M16 only, and is not supported on ControlLogix L8x controllers. For L8x controllers, quality will be 0x07 (CONFIG_ERROR and LIMIT_CONSTANT). |
RANGE: |
|
$SYS$FreeMemIO |
DWord/ |
Returns the total available I/O memory in number of bytes. This item is not supported on ControlLogix L8x controllers |
RANGE: |
|
$SYS$TotalMem |
DWord/ |
Returns the total memory, in number of bytes, in the Logix processor. This item is not supported on ControlLogix L8x controllers |
RANGE: |
|
$SYS$TotalMemDT |
DWord/ |
Returns the total available data table memory in number of bytes. This item is not applicable to 1756-L1, and is not supported on ControlLogix L8x controllers. |
RANGE: |
|
$SYS$TotalMemGM |
DWord/ |
Returns the total available general memory in number of bytes. This item is applicable to 1756-L55M16 only, and is not supported on ControlLogix L8x controllers. |
RANGE: |
|
$SYS$TotalMemIO |
DWord/ |
Returns the total available I/O memory in n umber of bytes. This item is not supported on ControlLogix L8x controllers |
RANGE: |
The following system items are supported by each communications node in the ABCIP Communication Driver, unless otherwise noted.
|
System Item Name |
Type/ Access Rights |
Description |
Values |
|---|---|---|---|
|
$SYS$OpenConnections |
DWord/ |
Returns the number of open CIP connections. |
RANGE: |
|
$SYS$ConnectionsInitiated |
DWord/ |
Returns the number of CIP connections initiated by the server. |
RANGE: |
|
$SYS$ConnectionsRefused |
DWord/ |
Returns the number of CIP connections refused by the communications module. |
RANGE: |
|
$SYS$RequestSent |
DWord/ |
Returns the number of message requests originating from the communications module. |
RANGE: |
|
$SYS$ReplyReceived |
DWord/ |
Returns the number of reply packets received. |
RANGE: |
|
$SYS$UnsolReceived |
DWord/ |
Returns the number of unsolicited messages received by the communications module. |
RANGE: |
|
$SYS$Unsolreplied |
DWord/ |
Returns the number of replies sent in response to the unsolicited message. |
RANGE: |
|
$SYS$RequestErrors |
DWord/ |
Returns the number of errors for the requests sent. |
RANGE: |
|
$SYS$RequestTimeout |
DWord/ |
Returns the number of request timed out |
RANGE: |
|
$SYS$ResetStatistics |
Boolean/ |
The item $SYS$ResetStatistics is available at root hierarchy PORT_CIP and will reset statistic counters of all child nodes. |
RANGE: |
|
$SYS$TotalPacketSent |
DWord/ |
Returns the number of data packets sent. |
RANGE: |
|
$SYS$TotalPacketReceived |
DWord/ |
Returns the number of replies received. |
RANGE: |
|
$SYS$RateSent |
DWord/ |
Returns the number of packets sent per second |
RANGE: |
|
$SYS$RateReceived |
DWord/ |
Returns the number of packets received per second. |
RANGE: |
|
$SYS$ItemUpdateRate |
DWord/ |
Returns the number of read items received per second. |
RANGE: |
|
$SYS$ItemWriteRate |
DWord/ |
Returns the number of write items sent out per second. |
RANGE: |
Important: The Redundant Hierarchy, including the Device Group, is not hot-configurable, and requires a Reset on the Redundant Hierarchy to effect a configuration change.