Hello, can someone please take a look at the attached screen shots and let me know why there are no values for the tags "T_Room" and "DI4"? I'm connected through a USB to Modbus RTU converter. The TX and RX lights are flashing on the converter, so I know its talking to the PLC. The first four screen shots are from the PLC software. I not sure how the scaling should be set up for analog status, however, I can't even get a value to show up for the digital status, like he does in the Youtube video here: https://youtu.be/Clt2uEIuL-E.

Sorry the pics uploaded in a random order.

Thanks.

Are you trying to read from COM6 while you are holding COM6 open while connected to the RTU?

Michael, I'm not sure what you mean by "holding COM6 open". The PLC software is not running at the same time as VTScada (I closed it - RX and TX lights are off when nothing is running). I can change the setting in VTScada to that either no RX or TX lights blink, or only the RX light blinks, or both the RX and TX blink. With the posted setting, both the RX and TX lights blink, which I assume this means VTScada is talking to the PLC. I just cant figure out why there are no values under the Tags section. Thanks for the reply.

I figured it out, with the help of my PLC manufacture. You need to determine what type of IO addresses your PLC manufacturer used first.

Holding Coils: 00001-09999
Input Coils: 10001-19999
Input Register: 30001-39999
Holding Register: 40001-49999

The first digit or 2 digits (not sure) determine the type of IO and combine with the address in the PLC to give the complete address. My manufacture only uses holding registers.

For example, if I assign any IO in the PLC the address of 101, the address I need to enter in VTScada will be 40101.

For 32 bit floating point addresses, subtract 1 from the address in the PLC.

For example, if I assign any IO in the PLC the address of 105, the address I need to enter in VTScada will be 40104.

Glad you got your addresses figured out. Looks like you are using Modbus, if so, you can see the additional data suffixes available to work with data other than 16-bit integers.

https://www.trihedral.com/help/Content/D_Tags/Dev_ModiconAddressing.htm

https://www.trihedral.com/help/Content/D_Tags/Dev_DataSuffixesForTagIO.htm

Hope those help