Hi,

I have this logic in snip on my logo8.4,

I'm moving 2 values to MQTT broker, 1 from digital input and another from an AM tag coming from analog input,

the sensor is measuring from 0-10 bar, but I have to scale it *100 in amplifier to show 2 decimals in LWE (345--->3.45 bar)

is there any way i can move real value(3.45 bar) to MQTT broker even as a string instead of moving it as a value*100(345)?

thanks in advance

ahmed_badawi

so, there is no chance I can move floating point to broker?!

I'm out of ideas how to do it!

What is the broker for this case? 
Why does it have to be in the specific format? 
What is the specification on the message that is sent out?

Can the engineering unit be changed from bar to mbar?

This forum and its volunteers are not the only avenue for you to get answers. You can use the Support Request service provided by Siemens who has access to the product developers.

1-we use our custom broker

2-client doesn't want to see integer value(2.51=3bar), he needs to see an accurate reading!

3- the broker is designed to accept LOGO JSON data 

4- unfortunately it should be in bar, not mbar

i already did a small trick, 

i used some math operations to split the float value into 2 numbers (3.5bar actual reading→ 35 in LOGO amplifier*10 → part1=3 &part2=5 to broker).

but i don't like it as it will give wrong values with negative ranges

ahmed_badawi49

1-we use our custom broker

2-client doesn't want to see integer value(2.51=3bar), he needs to see an accurate reading!

3- the broker is designed to accept LOGO JSON data 

4- unfortunately it should be in bar, not mbar

 

i already did a small trick, 

i used some math operations to split the float value into 2 numbers (3.5bar actual reading→ 35 in LOGO amplifier*10 → part1=3 &part2=5 to broker).

but i don't like it as it will give wrong values with negative ranges

Honestly I am out of my depth here - so see my answer as brainstorming.

Information from AI lets me to believe that the Integer/Float Conversion instruction could help. Test it. You will have to link to the VM that is assigned in the block.

 

yes, i already tried it without any difference, and VM tags is not in MQTT available tags(only V,VR,VX)

ahmed_badawi49

yes, i already tried it without any difference, and VM tags is not in MQTT available tags(only V,VR,VX)

Please try again. Refer to my notes in the attached picture. It is important that you transmit the VM (group name for Vx.x / VBx / VWx / VDx). 

Wow, thanks sir, it worked inside PLC but it's moved as double to broker and i have Dword/word/byte/bit choices in Type column in snip below

that's the shape of it inside MQTT client 

{"Pfloat":{"desc":"V-dword-0-1","value":[1051595899]}}

ahmed_badawi49

Wow, thanks sir, it worked inside PLC but it's moved as double to broker and i have Dword/word/byte/bit choices in Type column in snip below

that's the shape of it inside MQTT client 

{"Pfloat":{"desc":"V-dword-0-1","value":[1051595899]}}

{data} -> DEC -> 1051595899 -> HEX -> 3EAE147B -> FLOAT -> 0.34 
I am guessing that the number is the one you hope to get. 

The MQTT should interpret the data as a 32-bit floating point / Real number. In a strict sense DWORD is not the correct type. But it may only show the element size and not the actual type. The broker / client side should handle the data as a REAL I am not able to tell you how that is done.