Displaying the server time on a client

AlThePal · May 18, 2010, 11:14am

I want to display the server time on the screen of each client. Using a Client tag, I can set its Datatype to DateTime and useSELECT NOW()to return the time from the server, formatting it using the Metadata Format property. However, if I try to do the same using a SQLTag DB tag, the tag fails with an EXPRESSION_EVAL_ERROR.

Is there any reason I can’t use a DB tag to do this? Is there any difference in using a Client tag versus a DB tag? (I thought using a DB tag would mean the database was only queried once each scan interval and the results passed to every client, rather than each client issuing its own query to the database.)

Travis.Cox · May 18, 2010, 3:17pm

You have to select a database as the default to run queries in DB tags. So go into your gateway configuration section and select SQLTags -> Realtime. Edit the default provider and attach it to your database. Once attached the query should run.

AlThePal · May 18, 2010, 3:22pm

Thanks Travis, that sorted it.

Am I correct in thinking a DB tag would be more efficient than a Client tag here? (By efficient I mean less reads of the relational database.)

Travis.Cox · May 18, 2010, 3:36pm

Correct, it would only run once on the server and not on any clients.

AlThePal · May 18, 2010, 3:53pm

I’m trying to display the DB tag on-screen by dragging it to the window and choosing ‘Display/Label’. This binds the Text property of the label to the expressiondateFormat({Misc/serverTime}, {Misc/serverTime.FormatString})This displays correctly in the Designer, but when I try to save the window I get the following error:com.inductiveautomation.ignition.common.xmlserialization.SerializationException: Error during serialization for property 'propertyAdapters' on object '[FPMIWindow]Header' at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:291) at com.inductiveautomation.factorypmi.designer.xmlserialization.WindowDelegate.serializeProperties(WindowDelegate.java:37) at com.inductiveautomation.factorypmi.designer.xmlserialization.WindowDelegate.serialize(WindowDelegate.java:29) at com.inductiveautomation.ignition.common.xmlserialization.serialization.XMLSerializationContext.serialize(XMLSerializationContext.java:58) at com.inductiveautomation.ignition.common.xmlserialization.serialization.XMLSerializer.serialize(XMLSerializer.java:293) at com.inductiveautomation.factorypmi.designer.model.ObjectHolder.saveWindow(ObjectHolder.java:3316) at com.inductiveautomation.factorypmi.designer.model.ObjectHolder.commitWindow(ObjectHolder.java:3261) at com.inductiveautomation.factorypmi.designer.model.ObjectHolder.notifyProjectSaveStart(ObjectHolder.java:3543) at com.inductiveautomation.ignition.designer.IgnitionDesigner.handleSave(IgnitionDesigner.java:1100) at com.inductiveautomation.ignition.designer.IgnitionDesigner.access$2500(IgnitionDesigner.java:171) at com.inductiveautomation.ignition.designer.IgnitionDesigner$Handler.handleSaveAction(IgnitionDesigner.java:1652) at com.inductiveautomation.ignition.designer.IgnitionDesigner$Handler.access$1200(IgnitionDesigner.java:1245) at com.inductiveautomation.ignition.designer.IgnitionDesigner$Handler$6.actionPerformed(IgnitionDesigner.java:1360) at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.setPressed(Unknown Source) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source) at com.jidesoft.plaf.basic.BasicJideButtonListener.mouseReleased(Unknown Source) at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source) at java.awt.Component.processMouseEvent(Unknown Source) at javax.swing.JComponent.processMouseEvent(Unknown Source) at java.awt.Component.processEvent(Unknown Source) at java.awt.Container.processEvent(Unknown Source) at java.awt.Component.dispatchEventImpl(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Window.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) Caused by: com.inductiveautomation.ignition.common.xmlserialization.SerializationException: Error during serialization for property 'expression' on object '[ExpressionPropertyAdapter] ---> Label' at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:291) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serialize(DefaultObjectSerializationDelegate.java:312) at com.inductiveautomation.ignition.common.xmlserialization.serialization.XMLSerializationContext.serialize(XMLSerializationContext.java:58) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:204) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:193) at com.inductiveautomation.ignition.common.xmlserialization.serialization.delegates.MapDelegate.serializeElements(MapDelegate.java:42) at com.inductiveautomation.ignition.common.xmlserialization.serialization.delegates.MapDelegate.serialize(MapDelegate.java:32) at com.inductiveautomation.ignition.common.xmlserialization.serialization.XMLSerializationContext.serialize(XMLSerializationContext.java:58) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:204) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:193) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.doProperty(DefaultObjectSerializationDelegate.java:262) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:289) ... 39 more Caused by: com.inductiveautomation.ignition.common.xmlserialization.SerializationException: Error during serialization for property 'children' on object '[FunctionExpression]com.inductiveautomation.ignition.common.expressions.FunctionExpression@1e9843a' at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:291) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serialize(DefaultObjectSerializationDelegate.java:312) at com.inductiveautomation.ignition.common.xmlserialization.serialization.XMLSerializationContext.serialize(XMLSerializationContext.java:58) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:204) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:193) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.doProperty(DefaultObjectSerializationDelegate.java:262) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:289) ... 50 more Caused by: com.inductiveautomation.ignition.common.xmlserialization.SerializationException: Error during serialization for property 'tagListenerDelegate' on object '[BoundTagExpression]com.inductiveautomation.ignition.common.expressions.BoundTagExpression@1e83643' at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:291) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serialize(DefaultObjectSerializationDelegate.java:312) at com.inductiveautomation.ignition.common.xmlserialization.serialization.XMLSerializationContext.serialize(XMLSerializationContext.java:58) at com.inductiveautomation.ignition.common.xmlserialization.serialization.delegates.ArrayDelegate.serialize(ArrayDelegate.java:24) at com.inductiveautomation.ignition.common.xmlserialization.serialization.XMLSerializationContext.serialize(XMLSerializationContext.java:58) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:204) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:193) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.doProperty(DefaultObjectSerializationDelegate.java:262) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:289) ... 56 more Caused by: com.inductiveautomation.ignition.common.xmlserialization.SerializationException: Error during serialization for property 'tagValue' on object '[TagListener]com.inductiveautomation.ignition.common.expressions.TagListener@150a604' at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:291) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serialize(DefaultObjectSerializationDelegate.java:312) at com.inductiveautomation.ignition.common.xmlserialization.serialization.XMLSerializationContext.serialize(XMLSerializationContext.java:58) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:204) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:193) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.doProperty(DefaultObjectSerializationDelegate.java:262) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:289) ... 64 more Caused by: com.inductiveautomation.ignition.common.xmlserialization.SerializationException: Error during serialization for property 'value' on object '[BasicTagValue][2010-05-18 16:49:51.0,GOOD_DATA]' at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:291) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serialize(DefaultObjectSerializationDelegate.java:312) at com.inductiveautomation.ignition.common.xmlserialization.serialization.XMLSerializationContext.serialize(XMLSerializationContext.java:58) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:204) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:193) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.doProperty(DefaultObjectSerializationDelegate.java:262) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:289) ... 70 more Caused by: com.inductiveautomation.ignition.common.xmlserialization.SerializationException: Unable to create clean copy of class java.sql.Timestamp at com.inductiveautomation.ignition.common.xmlserialization.serialization.XMLSerializer.getCleanCopy(XMLSerializer.java:379) at com.inductiveautomation.ignition.common.xmlserialization.serialization.XMLSerializationContext.getCleanCopy(XMLSerializationContext.java:79) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:280) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serialize(DefaultObjectSerializationDelegate.java:312) at com.inductiveautomation.ignition.common.xmlserialization.serialization.XMLSerializationContext.serialize(XMLSerializationContext.java:58) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:204) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.writeCall(DefaultObjectSerializationDelegate.java:193) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.doProperty(DefaultObjectSerializationDelegate.java:262) at com.inductiveautomation.ignition.common.xmlserialization.serialization.DefaultObjectSerializationDelegate.serializeProperties(DefaultObjectSerializationDelegate.java:289) ... 76 moreWhen I delete the binding the window saves without error.

Carl.Gould · May 18, 2010, 6:23pm

This is fixed for the next release.