Device Standard Items

Overview

All protocol modules support diagnostic and counter items. These items can be helpful in solving communication problems and for other diagnostic checks. The items can reference a device, or a communication link to a device, or both.

Device Standard Items

Item	Data Type	Description	Readable or Readable and Writeable
AbortCurrentTask	Bool	Running this command on a device will abort any task currently being processed and lets the port moves on to the next device in its queue. It will not clear the queue for the device.	Both
ActualInterval<C1>	R4	This item is the actual interval at which the device on the primary/secondary connection was polled. It is updated each time all of the poll messages for the device have been sent. On Windows NT, it is accurate to 10 milliseconds.	Readable Only
Comments	String	This item displays the string entered into the Comments textbox of the object.	Readable Only
ConnectionOverride	I2	This item allows you to force the item to be polled on a specific connection. 0 = Controlled by ACM Configuration 1 = Primary Connection 2 = Secondary Connection	Both
ConnectString<C1>	R4	Some Port objects require information to connect to the specified device. Dialup and socket connections are two examples.	Readable Only
ContinuousScanSeconds	I4	The number of seconds to repeat all of the messages in the read queue until the time elapses. Set this item to the desired time and then write a 1 to the Demand item. The device will poll its advised items continuously until the time elapses.	Both
CurrentConnection	I2	A client application can use this item to determine which connection, primary or secondary, is currently being used to poll. This item is a one (1) if the primary connection is the current connection. It is a two (2) if the secondary connection is the current connection.	Readable Only
CurrentGoodConnection	I2	A client application can use this item to determine which connection, primary or secondary, was last used for a successful complete poll. This item is a one (1) if the last completed poll was on the primary connection. It is a two (2) if the last completed poll was on the secondary connection. During ACM startup, and until the device attempts its first poll, the item's value is zero (0).	Readable Only
Demand	Bool	Client (including ACM client) applications can use this item to force an immediate poll. When this item is set to one (1) the device object will perform a poll using both the primary and secondary connections just as if the poll interval had elapsed. Note: Performing a demand poll does not affect the poll interval. For example, if a poll interval is set for 10 minutes and a demand poll is performed three minutes into the elapsed time, the next interval poll will still be performed 7 minutes later. When a demand poll is triggered by a client application, the Demand item will remain a one (1) until the demand poll is complete. At that time the demand poll item will return to zero (0).	Both
DemandIntervals	I4	A bitmask of the intervals (1-15) that are queued for a demand poll. This item can be written to demand poll specific intervals. When the demand polls are done, the item’s value will return to zero.	Both
Description	String	This item displays the string entered into the Description textbox of the object.	Readable Only
DumpItemList	Bool	Write a “TRUE” to this item to make the device send its item list to the logger.	Both
Enabled	Bool	Displays whether or not the object is enabled.	Readable Only
FldAllocDif	I4	The number of history fields that have been allocated and not freed. This is a diagnostic item to monitor memory usage.	Readable Only
FootprintLevel	I4	Log tracing information between ACM and the port objects and between the device objects. The valid footprint levels are: 0 – 9 None 10 – 19 Entry and Exit of all functions that cross component boundaries 20 – 29 Entry, Exit and Parameters of all functions that cross component boundaries and their parameters and return codes.	Both
IntervalSelect<C1>	UI1	Use this item to change which interval is the default interval. Interval 1 is the default interval unless a different value is written to this item. Any items that don’t have a specific interval assigned to them use the default interval.	Both
ItemAllocDiff	I4	The number of items allocated that have not been freed. This will typically be a large number. This is a diagnostic item to monitor memory usage.	Readable Only
LastPollStatus	Bool	The value of the item will be ‘true’ when ACM starts up. The value of the item will be ‘true’ while polling and all message requests result in a good response. The value of the item will be ‘false’ if any requests did not receive a good response after all message retries were exhausted. Note: error responses do not count as a ‘good response’ since the requested data was not returned. Other conditions, such as an interrupted poll, the device becoming disabled, or the port becoming disabled, will not affect the item’s value.	Readable Only
LogActivity	Bool	Client applications can use this item to control the information that is sent to the Log Viewer in the ACM Client. When this item is set to one (1), any change to the current configuration is sent to Log Viewer. To disable this action, reset this item to zero (0).	Both
LogConfig	Bool	Client applications can use this item to control the information that is sent to the Log Viewer in the ACM Client. When this item is set to one (1), any change to the current configuration is sent to Log Viewer. To disable this action, reset this item to zero (0).	Both
LogDataFromClient	Bool	Client applications can use this item to control the information that is sent to the Log Viewer in the ACM Client. When this item is set to one (1), any change to the current configuration is sent to Log Viewer. To disable this action, reset this item to zero (0).	Both
LogDataFromDevice	Bool	Client applications can use this item to control the information that is sent to the Log Viewer in the ACM Client. When this item is set to one (1), any change to the current configuration is sent to Log Viewer. To disable this action, reset this item to zero (0).	Both
LogDataToClient	Bool	Client applications can use this item to control the information that is sent to the Log Viewer in the ACM Client. When this item is set to one (1), any change to the current configuration is sent to Log Viewer. To disable this action, reset this item to zero (0).	Both
LogDataToDevice	Bool	Client applications can use this item to control the information that is sent to the Log Viewer in the ACM Client. When this item is set to one (1), any change to the current configuration is sent to Log Viewer. To disable this action, reset this item to zero (0).	Both
LogErrors	Bool	Client applications can use this item to control the information that is sent to the Log Viewer in the ACM Client. When this item is set to one (1), any change to the current configuration is sent to Log Viewer. To disable this action, reset this item to zero (0).	Both
LogMsgItems	Bool	This log option is a bit mask consisting of all logging options. Client applications can use this item to control the information that is sent to the ACM Logger program. When this item is set to one (1), the protocol module will send a message to ACM Logger whenever it loses or regains communication with its primary or secondary connection. Note: The same result can be achieved through configuration by selecting the 'Status changes' option in the Logging setup screen.	Both
LogOptions	Bool	Client applications can use this item to control the information that is sent to the Log Viewer in the ACM Client. When this item is set to one (1), any change to the current configuration is sent to Log Viewer. To disable this action, reset this item to zero (0).	Both
LogRxData	Bool	Client applications can use this item to control the information that is sent to the Log Viewer in the ACM Client. When this item is set to one (1), any change to the current configuration is sent to Log Viewer. To disable this action, reset this item to zero (0).	Both
LogStatus	Bool	Client applications can use this item to control the information that is sent to the Log Viewer in the ACM Client. When this item is set to one (1), any change to the current configuration is sent to Log Viewer. To disable this action, reset this item to zero (0).	Both
LogUnsolicitedData	Bool	Client applications can use this item to control the information that is sent to the Log Viewer in the ACM Client. When this item is set to one (1), any change to the current configuration is sent to Log Viewer. To disable this action, reset this item to zero (0).	Both
MsgAllocDiff	I4	The number of poll messages allocated that has not been freed. This will typically be a non-zero number. This is a diagnostic item to monitor memory usage.	Readable Only
Pause	Bool	Client applications can use this item to suspend polling. When this item is set to one (1) the device object will not perform polls (including writes) on either the primary or secondary connections. When this item is set to zero (0) the device object will resume polling. Note: If polling has been suspended using the Pause item, un-Pausing will not produce an immediate poll. The next poll will occur at the next regularly scheduled interval, just as if polling had never been suspended. However, if there is a pending write messages in the write queue, the protocol module will send the write polls when it is un-Paused. If the poll interval is infrequent, the Demand item can be used to trigger a poll has been resumed.	Both
PollEnable	I2	This is a Read/Write item. A Value of 1 means the device is disabled or paused. A Value of 3 means the device is enabled and not paused. Any values other than 1 and 3 that are written to the item will be rejected. If a value of 1 is written to the item, the value of the “Pause” item will change to ‘true’ (preventing polls). If a value of 3 is written to the item and the device is enabled, the value of the “Pause” item will change to ‘false’ (allowing polls). If an OPC write is received with a value of 3 (to make the device poll) and the device is disabled, the item will echo back a value of 1 to indicate the device is disabled. This item's value will have to change when the enabled state changes and when the pause item's value is changed.	Both
PurgeWrites	Bool	Write (1) to purge all write messages that may have remained in the queue.	Both
QueuedInterrupts	I4	The number of interrupted poll sessions that are waiting to resume.	Readable Only
QueuedReads	I4	The total number of poll messages to read data that is in the queue for the primary and secondary connections. Note: There are two types of messages, Reads and Writes. Write messages have priority over Read messages - all Write messages will be processed before Read messages. Read messages are created based on the items activated by client applications, therefore, the number of Read messages in the queue generally does not change very often. Write messages are created when client applications change a value that must be sent to the device. Therefore, the number of write messages may change more often but should always decrement down to zero (0).	Readable Only
QueuedWrites	I4	The total number of poll messages to write data that is in the queue for the primary and secondary connections. Note: There are two types of messages, Reads and Writes. Write messages have priority over Read messages - all Write messages will be processed before Read messages. Read messages are created based on the items activated by client applications, therefore, the number of Read messages in the queue generally does not change very often. Write messages are created when client applications change a value that must be sent to the device. Therefore, the number of write messages may change more often but should always decrement down to zero (0).	Readable Only
RecAllocDiff	I4	The number of history or meter configuration polls allocated that has not been freed. This will typically be a non-zero number. This is a diagnostic item to monitor memory usage.	Readable Only
SingleWrite	Bool	Client applications can use this item to control the way write messages are sent to a device. Some protocols support combining multiple write messages into a single message. If this is the case, this behavior can be enabled or disabled using this item. To force the protocol module to send each write message individually to the primary and secondary connections, set this item to one (1). To allow the protocol module to combine writes set this item to zero (0).	Both
TestCommunication*	String	This item is used to test the communication to a device. To use, write a one (1) to this item and ACM will attempt to poll a known OPC item from this device. If successful, the log viewer will indicate that it was successful, and the item will display text that states: “Successful communication test at (n)” where (n) is the timestamp that the Test Communication was run. If not successful, the log viewer will indicate that it failed, and the item will display text that states: “Failed communication test at (n)” where (n) is the timestamp that the Test Communication was run. *This Item may not be present on some device protocols.	Both