# Gateway Tag Change Script or Local Tag Change Script **URL:** \ **Category:** Ignition\ **Tags:** scripting\ **Created:** [December 27, 2024, 6:54pm UTC](https://forum.inductiveautomation.com/t/gateway-tag-change-script-or-local-tag-change-script/100275 "2024-12-27T18:54:23Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Robert\_Thompson](https://avatars.discourse-cdn.com/v4/letter/r/edb3f5/32.png) [@Robert\_Thompson](https://forum.inductiveautomation.com/u/Robert_Thompson)\ **Post date:** [December 27, 2024, 6:54pm UTC](https://forum.inductiveautomation.com/t/gateway-tag-change-script-or-local-tag-change-script/100275/1 "2024-12-27T18:54:23Z")
Is there any difference between the Gateway Event, Tag Change and the Script function on a tag for value change? I see the Gateway Event can be configured for several items including tag change. I'm just wondering if I should make the script a gateway event or leave it a local tag change. The problem I see is the tag remains on and the tag will not run a second time. ```python def valueChanged(tag, tagPath, previousValue, currentValue, initialChange, missedEvents): trigger=system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/GetPLC912Data.value") trigger=trigger[0].value if trigger == 1: recname = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Data_Input_912/Recipe_Name.value") recname=recname[0].value EndDate = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Times_Input_912/StopTime.value") EndDate=EndDate[0].value recipe = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Data_Input_912/Recipe_Number.value") recipe=recipe[0].value skid = 912 StartDate = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Times_Input_912/StartTime.value") StartDate=StartDate[0].value unit = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Data_Input_912/Unit_Number.value") unit=unit[0].value params={"EndDate":EndDate,"Recipe":recipe,"RecipeName":recname,"Skid":skid,"StartDate":StartDate,"Unit":unit} ret=system.db.runNamedQuery("NXM_OEE","CIP/CIPInsert", params) PK=system.db.runNamedQuery("NXM_OEE","CIP/CIPGetPK") x=0 for x in range(38): cond = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Data_Input_912/Step"+str(x)+"/Conductivity_SP.value") cond=cond[0].value pumpsp = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Data_Input_912/Step"+str(x)+"/Pump_SP.value") pumpsp=pumpsp[0].value EndDate = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Times_Input_912/Step"+str(x)+"/StopTime.value") EndDate=EndDate[0].value StartDate = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Times_Input_912/Step"+str(x)+"/StartTime.value") StartDate=StartDate[0].value stepname = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Data_Input_912/Step"+str(x)+"/Step_Name.value") stepname=stepname[0].value stepnum = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Data_Input_912/Step"+str(x)+"/Step_Number.value") stepnum=stepnum[0].value steptimesp = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Data_Input_912/Step"+str(x)+"/Step_Time_SP.value") steptimesp=steptimesp[0].value suptimesp = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Data_Input_912/Step"+str(x)+"/Supervision_Step_Time_SP.value") suptimesp=suptimesp[0].value tempsp = system.tag.readBlocking("[New Castle]NXN-HHC CIP/912_CIP/CIP_Report_Data_Input_912/Step"+str(x)+"/Temperature_SP.value") tempsp=tempsp[0].value params={"EndDate":EndDate,"PK":PK,"PumpSP":pumpsp,"StepName":stepname,"StepNum":stepnum,"StartDate":StartDate,"SVTimeSP":suptimesp,"TempSP":tempsp,"TimeSP":steptimesp,"CondSP":cond} if (EndDate <> "0002-11-30 00:00:00" and stepname <> ""): ret=system.db.runNamedQuery("NXM_OEE","CIP/CIPStepInsert", params) system.tag.writeBlocking("[New Castle]NXN-HHC CIP/912_CIP/GetPLC912Data.value",[False]) ``` Here is the script for reference. The script runs when GetPLC912Data goes positive. Thank you for any comments. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [December 27, 2024, 8:29pm UTC](https://forum.inductiveautomation.com/t/gateway-tag-change-script-or-local-tag-change-script/100275/2 "2024-12-27T20:29:57Z")
> [@Robert\_Thompson](#): > > any difference Oh, yes. Your script is very much unsuitable for definition on the tag itself. Some reading and further links: > [@PLC to Ignition Interactions](https://forum.inductiveautomation.com/t/plc-to-ignition-interactions/99896/5): > > There are pros and cons. (Numerous discussions here on those.) But it is almost always preferable to system.util.invokeAsynchronous(). Starting new threads is a performance killer, and can run wild if you aren't careful. Discussions like these (and more, if you tweak the search terms): [https://forum.inductiveautomation.com/search?q=gateway%20tag%20change%20event%20valueChange%20thread%20pool%20order%3Alatest](https://forum.inductiveautomation.com/search?q=gateway%20tag%20change%20event%20valueChange%20thread%20pool%20order%3Alatest) If you have a particular need for valueChange scripting, but also need to not bloc… ---
**Author:** ![Robert\_Thompson](https://avatars.discourse-cdn.com/v4/letter/r/edb3f5/32.png) [@Robert\_Thompson](https://forum.inductiveautomation.com/u/Robert_Thompson)\ **Post date:** [December 27, 2024, 8:45pm UTC](https://forum.inductiveautomation.com/t/gateway-tag-change-script-or-local-tag-change-script/100275/3 "2024-12-27T20:45:17Z")
Thank you. I found some discussions about when to use a gateway script. I changed the script to a gateway function today. Thank you for the reply. Have a great weekend!