E!cockpit JSON string, sort data

CODESYS
,
#1

Hello. I’m trying and retrieve information from a JSON file. I manage to pick up the json string. But I can’t sort the data with WagoAppJSON.FbWrite_ToIEC_ByRule.
The data I try and retrieve is electricity prices in Norway during 24 hours.

link to json file https://www.hvakosterstrommen.no/api/v1/prices/2022/10-30_NO5.json

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VAR
	FbWrite_ToIEC_ByRuleStrom		: WagoAppJSON.FbWrite_ToIEC_ByRule;		// Function block to sort the info from the JSON file
	stringPath						: STRING(20):='/';						// Path the JSON file uses
	My1								: FbWrite_ToIEC_ByRule;
 	xHttpsGetTrigger2				: BOOL;
	xWriteToIEC_Error				: BOOL;
	iWriteToIEC_ActualArrayRow		: INT;

	MyJsonData		: ARRAY[0..23] OF typEnergyPrice;						// JSON data to sort the data inn
	
	bTestRule		: ARRAY[0..MAX_ARRAY_ELEMENTS_CUSTOM] OF typRuleBase:=[								
							(sPath:='NOK_per_kWh',iConvertType:=eReal),		// 1
							(sPath:='EUR_per_kWh',iConvertType:=eReal),		// 2
							(sPath:='EXR',iConvertType:=eReal),				// 3
							(sPath:='time_start',iConvertType:=eString),	// 4	Tride to use eTime but got error
							(sPath:='time_end',iConvertType:=eString)		// 5
						];
END_VAR 

FbWrite_ToIEC_ByRuleStrom(														// Function block to sort the info from the JSON file
	sPathBase:= stringPath, 
	pDataIn:= ADR(unHttpsGetRxBuffer.sVar), 
	udiSizeDataIn:= SIZEOF(unHttpsGetRxBuffer.abVar), 
	aRule:= bTestRule, 
	pIecVariable:= ADR(MyJsonData), 
	iArraySizeIecVariable:= 24, 
	udiSizeIecVariable:= SIZEOF(MyJsonData), 
	xError=> xWriteToIEC_Error, 
	iActualArrayRow=> iWriteToIEC_ActualArrayRow, 
	xTrigger:= xHttpsGetTrigger2 );												// xHttpsGetTrigger2 = TRUE to run

I made a GitLab project with all the info inn.
https://gitlab.com/espenbo/Codesys_JSON_hvakosterstrommen/-/tree/main

I’ll be happy if someone can help. Mabey I could make a HowTo for other that are trying the same.

#2

Hi @espenbo ,
For this purpose, the SAX parser of the WagoAppJSON is perfect.
You just need to define the token, and the associated rule to process the string data.

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You’ll find attached the way to implement it in your example.
eCockpit_Json.txt (139.7 KB)
(This is an export file change the extension file to .export)
Set xTriggerJSONParser to start the parsing process.

3 Likes
#3

Thanks.
I got it to work. Get my prices. I added a sort function. And fixed a bug when the days a between 1 and 9.

I Uploaded a new version on GitLab if someone else is interested.

1 Like
#4

I see that you created some big function for formatting time, take a look at WagoAppString.TimeComponents_To_String where you can easy format time/date:

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2 Likes
#5

I am continuing to work on this project and have added HMI tables. I also added extra information in typEnergyPrice.
There I added iArrayPlace to have an overview of where in the array the info is located when I sort from cheap to most expensive. But when I added iArrayPlace then I get weird values in HMI tables

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In array 1, 3, 5, etc., I get 125.0 as the value. But when I look in the SortedJsonData Array, I don’t get those values.

When I remove. iArrayPlace : INT;

TYPE typEnergyPrice :
STRUCT
	NOK_per_kWh		: REAL;
	EUR_per_kWh		: REAL;
	EXR				: REAL;
	time_start		: DATE_AND_TIME;
	time_end		: DATE_AND_TIME;
	NOK_per_kWh_mva : REAL;
//	iArrayPlace		: INT;
END_STRUCT
END_TYPE

AND the sorthing in HTTP_HvaKosterStrommen. I get the right vaules in tables inn HMI.

// Add array placement in array	
//	FOR i := 0 TO (n) DO
//		SortedJsonData[i].iArrayPlace := i;
//	END_FOR

I have tride to delete the tables in HMI and add it back. But I get the same result.

Code at GitLab

2 Likes
#6

delete “{attribute ‘pack_mode’ := ‘0’}” from typEnergyPrice
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