subscribeValues Function
In order to be notified of any changes of value in properties, the subscribeValues
method allows subscribing to one or multiple properties in a Desigo CC system and executing a method when the values change.
It is possible to specify a fixed list of objects to which subscribe to, but it is also possible to provide a filter and the subscription will be dynamically applied to all the objects that match the filter. When a property changes its value, the callback method provided as parameter will be invoked. The script runs until at least one subscription is active and keeps the script alive. When the script is stopped, all the subscriptions are removed.
Syntax
It is possible to subscribe to the change of value in properties of one system object. See the following syntax:
(one instruction)
subscribeValues(<objectReference>, <propertyNames>, <callback>, <initialValue>, <singleValues>);
(two instructions with variable)
var obj = new BrowserObject(<objectReference>);
var result = subscribeValues(obj, <propertyNames>, <callback>, <initialValue>, <singleValues>);
It is possible to subscribe to the change of value in properties of many system objects. See the following syntax:
(one instruction)
subscribeValues(<BrowserObjects array>, <propertyNames>,
<callback>, <initialValue>, <singleValues>);
(multiple instructions with variables)
var obj1 = new BrowserObject(<objectReference1>);
var obj2 = new BrowserObject(<objectReference2>);
...
var objN = new BrowserObject(<objectReferenceN>);
var result = subscribeValues([obj1, obj2, ..., objN], [<propertyNames>], <callback>, <initialValue>, <singleValues>);
It is also possible to create a dynamic subscription providing a filter by designation, object model, or alias. See the following syntax:
var result = subscribeValues(<filter>, <propertyNames>, <callback>, <initialValue>)
For example:
var filter = new Filter();
filter.designation= "System1.ApplicationView:ApplicationView.Logics.Scripts";
subscribeValues(filter, "Notes", callback);
Parameters Usage
Parameter | Type | Default | Use | Annotation |
objectReference
objectReferences | String String Array BrowserObject Array Point Array | - | Mandatory | CNS full path (reference to the system object location). For example: |
filter | - | Mandatory | Filter for the dynamic subscription. For further reference about this object, see Supported Filters below. | |
propertyNames | String String Array | - | Mandatory | Names of the properties for the subscription, or constants with values. For further reference about this parameter, see the notes below. |
callback | - | - | Reference to the method that will be executed when changes of value occur. The format is | |
initialValue | Boolean | True | Optional | If True, the callback method is called with the initial values of the concerned properties. In a If False, the callback method is called after the values change for the concerned properties. |
singleValues | Boolean | False | Optional | If True, the callback method is called for any changed property (in addition to any fixed properties). If False, the callback method is called for all the properties of the concerned system object. Note that the |
Supported Filters
filter.designation:
system object path, from root to object. For example, Scripts designation is:"System1.ApplicationView:ApplicationView.Logics.Scripts"
.
It is possible to specify the designation with a specific wildcard character (*), at the end of the designation. By specifying this filter, the subscription will be applied to all the child nodes of the specified object. For example, if the designation of Scripts node is specified, the subscription will be applied to all its child nodes.
It is also possible to specify the designation of a node that does not exist, but in this case it is necessary to provide the full designation (System.View:path). The subscription will be accepted, and it will be applied to all the child nodes that belong to this node when it is created, without restarting the script.
A filter by designation can be used in conjunction with the other conditions (alias and object model). For example:var filter = new Filter();
or
filter.designation= "System1.ApplicationView:ApplicationView.Logics.Scripts";
filter.alias = "alias";
subscribeValues(filter, "Notes", callback);var filter = new Filter();
filter.designation= "System1.ApplicationView:ApplicationView.Logics.Scripts";
filter.alias = "alias";
filter.objectModel = "GMS_Script";
subscribeValues(filter, "Notes", callback);
filter.objectModel
: filter condition in dynamic subscriptions where the filter will be applied to a set of points that is not fixed, but that can change over time in case of creation/deletion of points. For example, consider executing a subscription with a filter object for ObjectModel="GMS_Virtual_Analog":
- When the subscription is executed in the script, it will be applied to all the objects that have "GMS_Virtual_Analog" as object model.
- While the subscription is running, if a new instance with object model="GMS_Virtual_Analog" is created, the subscription will start monitoring the properties of this instance. Therefore, if the subscribed property of such object changes value, the callback method will be invoked.filter.alias:
filter condition in dynamic subscriptions where the alias is a string that can be used to identify a single data point. It is set using the Object Configurator application and it is not possible to assign the same alias to more than one data point. A dynamic subscription with alias as filter condition will monitor the alias attribute of objects. If a matching alias is set for an object, such object will be included in the subscription. It is possible to specify the alias condition with wildcards, but case sensitive is always True (system limit).
It is also possible to combine the alias filter and the objectModel filter. In this case, the subscription will be applied to all the data points that match both the filter conditions.
Additional Notes for the <propertyNames> object
- When an individual property is concerned, it is possible to directly specify the name of the property as string. For example: "
Present_Value"
. - When many properties are concerned, it is necessary to create an array containing the names of all the desired properties. For example,
["Value", "Priority"]
. - It is possible to specify properties with fixed values, such as constants that are notified in the callback along with the other concerned properties. For example:
["Value", "MyConstantValue=3"]
. - The system objects can be of different types (different object models), as long as the subscription is done on properties having the same name. For example, you can subscribe to a BACnet Analog Input and a BACnet Binary Input at the same time, as long as the
<propertyNames>
object contains properties defined in both the object models (for example,Present_Value
is correct, whilePolarity
will result in a subscription failure, because it is defined only for BACnet Binary Input.)
Callback
Function
The callback method is called when any concerned property of a system object changes.
Syntax
The callback function must be declared as follows:
function myCallback(<changedObject>, <changedPropertiesAndValues>) {
//... Do callback stuff here ...
}
Where:
<changedObject>
is the system object to which it is subscribed and whose properties changed. It is possible to access its attributes via theAttributes
property of the system object. This object can be used afterwards in other operations taking an object as input such as, read, getCommandList, executePropertyCommand, and so on.
It is possible to print the designation of this object in one of the following ways:console("object = {0}", object);
console("object.ToString = {0}", object.ToString());
console("object.Designation = {0}", object.Designation);
<changedPropertiesAndValues>
is a dictionary (key-value pairs) that contains the changed properties (as keys) and the new property values. In particular, the names of the properties notified are the keys and the new (or fixed) values are the dictionary values.
Possible operations on<changedPropertiesAndValues>
(let's call it "values") are the following:- The
Count
field allows counting the changed properties.
//Get the count of the notified elements
var count = ChangedPropertiesAndValues.Count; - Use the JavaScript dot notation or bracket notation to access the dictionary property name.
//Get a specific property by name with dot notation
Once the property is accessed, it is possible to obtain its value using
var presentValueProperty = ChangedPropertiesAndValues.Present Value;
//Get a specific property by name with bracket notation
var presentValueProperty = ChangedPropertiesAndValues["Present_Value"];.Value
. - Access the value of the property
//Access the value of the property
var value = presentValueProperty.Value;
When calling the subscribeValues method, the callback function can be specified as string, object (including the function itself), inline (anonymous), or variable (which must be defined before use). Consequently, assuming to have the object object1 to which to subscribe to monitor the Value1 property, after declaring the function "MyCallback”
, the following calls of subscribeValues
can be executed:
var result = subscribeValues(object1, "Value1", "myCallback");
...
function myCallback (object, values) {
console("Callback called. Changed object: {0}", object);
}
var result = subscribeValues(object1, "Value1", myCallback);
...
function myCallback (object, values) {
console("Callback called. Changed object: {0}", object);
}
Alternatively, a callback can be defined as inline function (anonymous) as follows:
var result = subscribeValues(object1, "Value1", (function (object, values) {console("Inline callback called. Changed object: {0}", object); }));
Another option is to define a variable containing the callback function. For example:
var myF = function (object, values) {
console("myF callback called. Changed object = {0}", object);
}
...
var result = subscribeValues(object1, "Value1", myF);
When executing a script that includes a subscription and an instruction while(true)
in the callback, for example:
var result =
subscribeValues("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight",
"Value", onOrganizationModeChanged);
function onOrganizationModeChanged(object, values)
{
console("New value = {0}", values.Value.Value);
while(true) {}
}
- If the script timeout is not set (such as, Timeout = 00:00:00 hh:mm:ss), the script remains in Activity Status=
Running
until it is manually stopped; as soon as the first invocation of the callback arrives, no other value change is received, because the callback remains stuck during the execution of the instructionwhile(true)
. - If the script timeout is set, the script ends when the timeout expires (Last Execution Status is
Timed out
).
Result
- If the subscribe operation is successful, the result object contains the result of the
subscribeValues
method. - If any errors occurred during the subscribe operation, the
subscribeValues
method returns the SubscribeValuesResult object with the error that indicates the reason why the operation failed.
Error Handling
Errors can occur in case:
<objectReference>
is null or empty.result.error: "The designation is empty"/"Object is null"
<propertyNames>
is null, empty, or invalid (for example, they are not string values; or the property type is invalid; or the property names are duplicated; or have fixed values.result.error: "Invalid property."
- When subscribing to various properties of a system object but the system object does not have a property with the specified name.
result.error: "Property not found"
- The object type is invalid; null; or an empty string is passed among the subscription objects.
result.error: "Invalid object"
- The system object is invalid.
result.error: "Node not found (System1.MyObject)"
<callback>
:- Is null or empty
result.error: "Invalid callback"
- Is undefined. One of the following may happen:
- The script generates the exception"xyz is not defined"
and ends with an error.
- If the callback was specified as a string, the Script Manager cannot detect the missing callback before trying to execute it,result.error
:"Subscription succeeded"
while the script will continue running. Anyway, when a change of value comes in, the exception"Can only invoke functions"
is traced because the callback with the given name is undefined. - Wrong access to callback data. If a property is not among the property/value pairs returned in values, the instruction
values.MyProperty
generates an exception and the script ends. <filter>
:- Invalid filter object (such as the filter condition is different from designation, object model, or alias). The script ends with the following error:
Invalid filter for subscription: ##### filter is not supported
(where #### is the name of the filter property that is not supported). - No filter condition is specified. The script execution ends with the following error:
Invalid filter for subscription: no filter conditions are specified
- The filter by designation contains wildcard char * but in a different position from what expected. The script execution ends with the following error:
Invalid filter for subscription: you can only specify * wildcard at the end of designation filter
- The provided designation cannot be resolved, and it is not fully defined (it must define all fields: System.View:path). The script execution ends with the following error:
Invalid filter for subscription: the provided designation is invalid
Examples of Use
How to print the result of a subscribe call
An easy way to print the result of a subscribe call is to invoke the method ToString
or toString
on the result itself. For example:
console("{0}", result.ToString());
Or
console("{0}", result);
Or
console(result);
How to subscribe to the change of the Present_Value property of an Analog Value object, without receiving the initial value
var result = subscribeValues("System1.ManagementView:ManagementView.FieldNetworks.MyBACnetNet.Hardware.1600/1600Test_device.1600/0Local_IO.1600/1AV_1", ["Present Value"], "onPresentValueChanged", false);
console("{0}", result.toString());
...
function onPresentValueChanged(object, values) {
var presentValueItem = values.Present_Value;
console("Object: {0}; New value: {1}", object, presentValueItem.Value);
}
At the end of the subscription, the output in the Console expander is:
Subscription succeeded
When Present Value
changes in the monitored object, the output in the Console expander is:
"Object: System1.ManagementView:ManagementView.FieldNetworks.MyBACnetNet.Hardware.1600/1600Test_device.1600/0Local_IO.1600/1AV_1; New value: 45"
Note that the subscription was made without executing the callback function on the Initial Value. Also note that the callback function was passed as string while the presence of the Present_Value key was not checked in the dictionary of the modified values.
How to subscribe to the change of the Value property of DayNight and OnOff organization modes, using the same callback
var obj = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight");
var result = subscribeValues(obj, ["Value"], onOrganizationModeChanged);
console("Subscription1: {0}", result.toString());
var obj2 = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OnOff");
var result2 = subscribeValues(obj2, ["Value"], onOrganizationModeChanged);
console("Subscription2: {0}", result2.toString());
...
function onOrganizationModeChanged(object, values) {
var newValue = values.Value.Value;
console("Object = {0}; Value: {1}", object, newValue);
}
At the end of the subscription, the output in the Console expander is:
Subscription1: Subscription succeeded
Subscription2: Subscription succeeded
"Object = System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight; Value: 0"
"Object = System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OnOff; Value: 1"
When Value
changes for the DayNight monitored object, the output in the Console expander is:
"Object = System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight; Value: 1"
When Value
changes for the OnOff monitored object, the output in the Console expander is:
"Object = System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OnOff; Value: 0"
Note that the subscription was made with the execution of the callback function on the Initial Value. Also note that the same callback function was used because both the objects have the property named Value. The presence of the Value key was not checked in the dictionary of the modified values. Then the values were obtained using the field .Value
.
How to subscribe to the change of the Value property of two OPC Texts and one OPC Analog Input, using the same callback
Use a fixed property to distinguish the object types when the callback is invoked and write the newly notified value to an OPC Text or to an OPC Analog Output respectively.
var obj1 = new BrowserObject("System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text1");
var result1 = subscribeValues(obj1, ["Value", "PropertyType=Text"], onValueChanged, false);
console("Subscription1: {0}", result1.toString());
var obj2 = new BrowserObject("System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text2");
var result2 = subscribeValues(obj2, ["Value", "PropertyType=Text"], onValueChanged, false);
console("Subscription2: {0}", result2.toString());
var obj3 = new BrowserObject("System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_3.AnalogInput1");
var result3 = subscribeValues(obj3, ["Value", "PropertyType=AnalogInput"], onValueChanged, false);
console("Subscription3: {0}", result3.toString());
...
function onValueChanged(object, values) {
if (object == null || values == null) {
console("Invalid notification");
return;
}
var newValue = values["Value"].Value;
var propType = values.PropertyType.Value;
console("Object = {0}; Value: {1}; PropertyType = {2}", object, newValue, propType);
if (propType == "Text") {
//Write the new value to another OPC Text object
var obj = new BrowserObject("System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_2.Text3");
var result = executePropertyCommand(obj, "Value", "Write", newValue);
console("Text change => executePropertyCommand result: {0}", result.toString());
} else if (propType == "AnalogInput") {
//Write the new value to an OPC Analog Output object
var obj = new BrowserObject("System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_3.AnalogOutput1");
var result = executePropertyCommand(obj, "Value", "Write", newValue);
console("AnalogInput change => executePropertyCommand result: {0}", result.toString());
}
}
The result of the subscriptions in the Console expander is:
Subscription1: Subscription succeeded
Subscription2: Subscription succeeded
Subscription3: Subscription succeeded
When the Value
property of Text1 changes (obj1), the output in the Console expander is:
"Object = System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text1; Value: hello; PropertyType = Text Text change => executePropertyCommand result: Command succeeded"
When the Value
property of Text2 changes (obj2), the output in the Console expander is:
"Object = System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text2; Value: hello; PropertyType = Text Text change => executePropertyCommand result: Command succeeded"
When the Value
property of AnalogInput1 changes (obj3), the output in the Console expander is:
"Object = System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_3AnalogInput1; Value: 16.88; PropertyType = AnalogInput AnalogInput change => executePropertyCommand result: Command succeeded"
Note that each subscription was made without executing the callback function on the Initial Value. Each subscription was made on two properties of the object passing constant values to the callback function. A check was made of the modified values of the dictionary data. To access the dictionary properties dot notation and bracket notation were used. The executePropertyCommand
function was called to update the Value property of the objects Text3
and AnalogOutput1
.
How to subscribe to the change of value of various properties of a BACnet Analog Input, without receiving the initial value and requesting for single values
var obj = new BrowserObject("System1.ManagementView:ManagementView.FieldNetworks.MyBACnetNet.Hardware.1600/1600Test_device.1600/0Local_IO.1600/1AI_1");
var result = subscribeValues(obj, ["Present Value", "Out Of Service", "Low Limit", "High Limit", "MyConst = 5"], onAnalogInputChanged, false, true);
console("{0}", result);
...
function onAnalogInputChanged(object, values) {
if (object == null || values == null || values.Count == 0) {
console("Invalid notification");
return;
}
}
At the end of the subscription, the output in the Console expander is:
Subscription succeeded
At each change of value of one of the properties of the monitored object, the output in the Console expander is one of the following:
High_Limit = 0
MyConst = 5
or
Low_Limit = 0
MyConst = 5
or
Out_Of_Service = False
MyConst = 5
or
Present_Value = 42.347
MyConst = 5
Note that the subscription was made without the execution of the callback function on the Initial Value, but it was requested a notification about each change of value. Data was checked in the dictionary of the modified values. Also note that the bracket notation was used to access the dictionary property.
How to use an inline callback
var obj = new BrowserObject("System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text1");
var result = subscribeValues(obj, ["Value"], (function (object, values) { console("Inline callback called. Changed object: {0}", object); } ),true);
console("Subscription1: {0}", result);
At the end of the subscription, the output in the Console expander is:
Subscription succeeded
"Inline callback called. Changed object: System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text1"
When Value
changes for the monitored object, the output in the Console expander is:
"Inline callback called. Changed object: System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text1"
Note that the subscription was made with the execution of the callback function on the Initial Value. Also note the anonymous inline callback function in brackets while dictionary data for the modified values was not checked.
How to define and use a variable containing the callback function
var myFunction = function (object, values) {
console("Changed object = {0}", object);
}
...
var obj1 = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight");
var result1 = subscribeValues(obj1, ["Value"], myFunction);
console("Subscription1: {0}", result1);
var obj2 = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OnOff");
var result2 = subscribeValues(obj2, ["Value"], myFunction);
console("Subscription2: {0}", result2);
At the end of the subscription, the output in the Console expander is:
Subscription1: Subscription succeeded
Subscription2: Subscription succeeded
"Changed object = System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight"
"Changed object = System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OnOff"
When Value
changes for the monitored objects, the output in the Console expander is:
"Changed object = System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight"
Or
"Changed object = System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OnOff"
Note that the subscription was made with the execution of the callback function on the Initial Value. Also note that the callback is passed as a variable (defined before its use).
How to subscribe to the change of value of the Value property of the organization modes DayNight, OccupancyStatus, OnOff, OpenClose, OperationalStatus
var obj1 = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight");
var obj2 = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OccupancyStatus");
var obj3 = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OnOff");
var obj4 = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OpenClose");
var obj5 = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OperationalStatus");
var result = subscribeValues([obj1, obj2, obj3, obj4, obj5], ["Value"], onOrganizationModeChanged);
...
function onOrganizationModeChanged(object, values) {
var newValue = values.Value.Value;
console("Object = {0}; Value: {1}", object, newValue);
}
The callback will be invoked once per object and the output in the Console expander is the initial value of each property:
Object =
System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight;
Value: 0
Object =
System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OccupancyStatus;
Value: 0
Object =
System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OnOff;
Value: 0
Object =
System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OpenClose;
Value: 0
Object =
System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OperationalStatus;
Value: 0
Note that the subscription was made with the execution of the callback function on the Initial Value. Additionally, the callback function was passed as object. Since the <SingleValues>
parameter was not specified (and the default is False), the callback is called once per object in the subscription even if only one of the monitored objects changes.
How to perform the same subscription as in the previous example, but using strings instead of objects
var result = subscribeValues(["System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight", "System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OccupancyStatus", "System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OnOff", "System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OpenClose", "System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OperationalStatus, ["Value"],
onOrganizationModeChanged);
...
function onOrganizationModeChanged(object, values)
{
var newValue = values.Value.Value;
console("Object = {0}; Value: {1}", object, newValue);
The result is the same as in the previous example.
How to perform the same subscription as in the previous example, but using an array of mixed strings and objects
var obj1 = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight");
var obj2 = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OccupancyStatus");
var obj3 = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OnOff");
var result = subscribeValues([obj1, obj2, obj3, "System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OpenClose", "System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.OperationalStatus"], ["Value"], onOrganizationModeChanged);
...
function onOrganizationModeChanged(object, values) {
var newValue = values.Value.Value;
console("Object = {0}; Value: {1}", object, newValue);
}
The result is the same as in the previous examples.
How to subscribe to heterogeneous objects that have the property "Value" (of different types)
//Organization Mode Value is a GmsEnum
var obj1 = new BrowserObject("System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight");
//OPC Text Value is a PvssString
var obj2 = new BrowserObject("System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text1");
//OPC Analog Input Value is a GmsReal
var obj3 = new BrowserObject("System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_3.AnalogInput1");
//OPC Binary Input Value is a GmsBool
var obj4 = new BrowserObject("System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_3.BinaryInput1");
var result = subscribeValues([obj1, obj2, obj3, obj4], ["Value"], onValueChanged, true, true);
console("Subscription: {0}", result);
...
function onValueChanged(object, values) {
var newValue = values.Value.Value;
console("Object = {0}; Value: {1}", object, newValue);
}
The output in the Console expander at the end of the subscription is:
Subscription: Subscription succeeded
"Object = System1.ManagementView:ManagementView.SystemSettings.OrganizationModes.DayNight; Value: 0"
"Object = System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text1; Value: helloworld"
"Object = System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_3.AnalogInput1; Value: 5576"
"Object = System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_3.BinaryInput1; Value: False"
At any change of the Value
property of one of the monitored objects, the output in the Console expander Is (in this example obj2
):
"Object = System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text1; Value: My New Text1"
Note that the subscription was made on different objects that have the Value
property. The subscription was made with the execution of the callback function on the Initial Value. Additionally, the callback function was passed as object. Since the <SingleValues>
parameter was specified, the callback is called only once for the object that changed its value among those monitored by the subscription.
How to subscribe to the change of value of an OPC Text
var obj = new BrowserObject("System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text1");
var result = subscribeValues(obj, "Value", onValueChanged);
console("Subscription result: {0}", result.toString());
...
function onValueChanged(object, values) {
if (object == null || values == null) {
console("Invalid notification");
return;
}
var objectValue = values["Value"].value.value;
var objectQualityGood = values["Value"].value.qualityGood;
var objectQuality = values["Value"].value.quality;
var objectTimestampUTC = values["Value"].value.timestamp;
if (objectQualityGood == false)
console("Bad quality for {0}.", object);
else
console("Good quality for {0}. Value = {1}, Timestamp (UTC) = {2}", object, objectValue, objectTimestampUTC);
}
If this script is executed when the OPC DA driver is not running, the first notification indicates bad quality. Consequently, the output in the Console expander is similar to the following:
Subscription result: Subscription succeeded
Bad quality for
System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.
Once the OPC Server is started for simulation and the OPC DA driver, the output in the Console expander is similar to the following:
Good quality for
System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text1.
Value = Today, Timestamp (UTC) = 5/5/2015 9:51:47 AM
Good quality for
System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text1.
Value = --, Timestamp (UTC) = 5/5/2015 9:52:47 AM
Good quality for
System1.ManagementView:ManagementView.FieldNetworks.MyOPCNet.Server_Matrikon.Group_1.Text1.
Value = Your, Timestamp (UTC) = 5/5/2015 9:53:47 AM
How to subscribe with <initial value> = true and filter.designation
var filter = new Filter();
filter.designation= "System1.ApplicationView:ApplicationView.Logics.Scripts";
subscribeValues(filter, "Notes", callback, true);
function callback(object, values) {
console("{0} has changed", object);
}
If the script is executed with only one instance named “MyScript1”, the output in the Console expander is: "MyScript1 has changed"
.
If a new instance is created, named "MyScript2", the output in the Console expander also includes: "MyScript2 has changed"
.
Every time the Notes
property of MyScript1 or MyScript2 changes, the callback method will be executed, and a new message will display in the Console expander.
How to subscribe with <initial value> = False and filter.designation
var filter = new Filter();
filter.designation= "System1.ApplicationView:ApplicationView.Logics.Scripts";
subscribeValues(filter, "Notes", callback, false);
function callback(object, values) {
console("{0} has changed", object);
}
If the script is executed with only one instance , named "MyScript1", since <initial value>
is False
, the Console expander does not display any information. As soon as MyScript1.Notes
changes its value, the output is: "MyScript1 has changed"
.
If a new instance is created, named "MyScript2", again the Console expander does not display any information (<initial value>
is False
). As soon as MyScript2.Notes
changes its value, the output also includes: "MyScript2 has changed".
Every time the Notes
property of MyScript1 or MyScript2 changes, the callback method will be executed, and a new message will display in the Console expander.
How to subscribe with <initial value> = true and filter.objectModel
var filter = new Filter();
filter.objectModel = "GMS_Virtual_Analog";
subscribeValues(filter, "Value", callback, true);
...
function callback(object, values) {
console("{0} has changed", object);
}
If the script is executed with only one instance with ObjectModel="GMS_Virtual_Analog", named "MyPoint1", the output in the Console expander is: "MyPoint1 has changed"
.
If a new instance of the same ObjectModel is created, named "MyPoint2", the output also includes: "MyPoint2 has changed"
.
Every time the Value
property of MyPoint1 or MyPoint2 changes, the callback method will be executed, and a new message will display in the Console expander.
Note that the subscription is made by executing the callback function on the initial value and when the objects were created.
How to subscribe with <initial value> = False and filter.objectModel
var filter = new Filter();
filter.objectModel = "GMS_Virtual_Analog";
subscribeValues(filter, "Value", callback, false);
...
function callback(object, values) {
console("{0} has changed", object);
}
If the script is executed with only one instance with ObjectModel="GMS_Virtual_Analog", named "MyPoint1", since <initial value>
is False, the Console expander does not display any information. As soon as MyPoint1.Value
changes its value, the output is: "MyPoint1 has changed"
.
If a new instance of the same object model is created, named "MyPoint2", again the Console expander does not show any information (<initial value>
is False). As soon as MyPoint2.Value
changes its value, the output in the Console expander is: "MyPoint2 has changed"
.
Note that the subscription is made by executing the callback function on the initial value and when the objects were created.
How to subscribe with <initial value> = true and filter.alias
var filter = new Filter();
filter.alias= "alias*";
subscribeValues(filter, "Value", callback, true);
...
function callback(object, values) {
console("{0} has changed", object);
}
If the script is executed when there is only one instance with alias="alias1", named "MyPoint1", the output in the Console expander is: "MyPoint1 has changed"
.
If a new data point instance is created, named "MyPoint2", with alias = "alias2", the output in the Console expander is: "MyPoint2 has changed"
.
Every time the Value
property of MyPoint1 or MyPoint2 changes, the callback method will be executed, and a new message will display in the Console expander.
How to subscribe with <initial value> = False and filter.alias
var filter = new Filter();
filter.alias= "alias*";
subscribeValues(filter, "Value", callback, false);
...
function callback(object, values) {
console("{0} has changed", object);
}
If the script is executed when there is only one instance with alias="alias1", named "MyPoint1", since <initial value>
is False
, the Console expander does not display any information. As soon as MyPoint1.Value
changes its value, the output is: "MyPoint1 has changed"
.
If a new instance of the same data point is created, named "MyPoint2", again the Console expander does not display any information (<initial value>
is False). As soon as MyPoint2.Value
changes its value, the output in the Console expander is: "MyPoint2 has changed"
.
Every time the Value
property of MyPoint1 or MyPoint2 changes, the callback method will be executed, and a new message will display in the Console expander.
How to use a combined filter (alias and object model)
var filter = new Filter();
filter.alias = "alias*";
filter.objectModel = "GMS_Virtual_Analog";
subscribeValues(filter, "Value", callback);