Hi,

one way you can do it is to set the word value to the correct number, so that word will just raise the deisred bit.

For example set word to 1 if you want first bit, 2 for second bit, 4 for third, 8 for forth and so on. Be careful of eventual byte swap in word (order of byte inverted).

Another way is to use the HMI Function "SetBitInTag".

Another way is to use SCL and the "AT" construct to build a bit mask on the word you want to set the bit.

If you open the tag table in the HMI and add a new HMI tag of the type Bool, you can add the address manually if you select "PLC tag" as "None" and then enter the address of the %DB3.DBW0 for bit 0 and so forth.

Then you can select the individual bits in the HMI.

BoletusEdulis

Another way is to use SCL and the "AT" construct to build a bit mask on the word you want to set the bit.

 Hi I want to know more about this .

mxj262

 

BoletusEdulis

Another way is to use SCL and the "AT" construct to build a bit mask on the word you want to set the bit.

 Hi I want to know more about this .

Hi, you can check these links.

• AT construct: https://support.industry.siemens.com/cs/ww/en/view/57132240  
• Memory Slicing (more efficient): https://support.industry.siemens.com/cs/ww/en/view/57374718 

Hello mxj262,

I would suggest just using additional BOOL variables (probably within the same DB), which are intended for HMI data exchange (like HMI buffer), and then pack-unpack into the target WORD variable with the PLC program.

This approach lets you stay independent from individual features of a PLC or HMI (like this, that some HMIs support bit addressing within WORD variables while others don't).

Michael K

If you open the tag table in the HMI and add a new HMI tag of the type Bool, you can add the address manually if you select "PLC tag" as "None" and then enter the address of the %DB3.DBW0 for bit 0 and so forth.

Then you can select the individual bits in the HMI.

 Hi Michael,

I feel like your suggestion is what I am looking for, but I am unable to proceed without further help...
My problem: I need to direct access in HMI tag DB50.DBW20 (tag name LEDKeyF1F8), where single bits of Word represents LED keys F1 to F8.

I am doing retrofit - new Siemens HMI, connecting with CPU 416F-3. making 1:1 to previously used Movicon HMI. So... I cannot anyhow use PLC level in this case. (in SCL code access .%X1 from DBW and so on). I just need to access this directly as HMI tag. In ideal world I would expect I can access my tag named LEDKeyF1F8 (address DB50.DBW20) as LEDKeyF1F8.%X1 for accessing first bit, but it is not working.

Could you please help me and describe this a bit more to detail how could I do this workaround?

Many thanks in advance
 

Hi Kilca,

If your individual LED is already represented in HMI variable "LEDKeyF1F8" then you can just use this directly in animations.

I don't know which HMI (what WinCC) you use, but there are animations where you point to the word and then based on a specific bit, you make a color change.

This way you do not need to exchange 8 individual tags but can use just one instead.

I hope this helps

Regards

In HMI KTP400 Basic (I suppose also in others)
you can only address bits in bytes. You cannot
address bits in words. Therefore, addressing,
for example, %DB1.DBW0.0 will be invalid, but
you can address a bit in a byte to %DB1.DBX0.0.

Mariusz Terebecki