already posted some questions earlier regarding logging data, i get everything to work properly except for LOGTAG to just log a single value when it changes.

startlogging works fine but logtag just doesnt log anything. 

using a ktp900 (wincc) sim and tia 15.1. 

so what i do: 

1. created a plc trigger boolean and paired it to hmi tag

2. hmi trigger -> properties ->set acquisition cycle continously 100ms

3. hmi trigger -> events -> value change -> logtag(testvalue)

4. historical data ->created data_log -> logging method circular

5. historical data -> logging tags -> testvalue -> logging method ( on demand) 

see attached file for clear view.

every 500ms the clock bit changes the hmi trigger and then it should execute the logtag right?

Hello,

What happens when 'Logging method' is "trigger event"? (And not circular log)

Best regards,

Wizard

nothing changes, no data is written to the log.. 

Hello,

Does both tags have the property: acquisition mode: Cyclic continuous?

Best regards,

Wizard

Hello mittens,

how do you start the logging? - In your screenshot the "Enable logging at runtime start" is not activated.

Regards,

Frink

hello,

i start the logging by a bit on the plc (on top of the image) you see that i use a 0,5hz clock bit to trigger a bit on the hmi. i turned of start log on runtime on purpose so i know when it is logging when it is supposed to.

hello,

all tags are set to cyclic continious.

 Hello mittens,

mittens

hello,

i start the logging by a bit on the plc (on top of the image) you see that i use a 0,5hz clock bit to trigger a bit on the hmi. i turned of start log on runtime on purpose so i know when it is logging when it is supposed to.

the 0,5hz clock bit is not enabling the logging. It gives the signal when the system should write the tag value(s) to the log.

Either you activate "enable logging when runtime starts" or you have to enable it with the following system function, e.g. when pressing a button or by use of a script:

StartLogging data_log_1

Regards,

Frink