I don't know how to create the ladder diagram. I will be glad if you help.

Hello Frisby;

There are some discussions strated on the forum discussing the onnection of a s7-200 CPU with a Delta DOP-B HMi. Most answers are inconclusibve, unfortunately.

This external link provides a guide and a video demonstartion of this connection.

https://365electricalvn.com/how-to-connect-plc-and-hmi-s7-200-delta-dop-b-communication/

I cannot vouch for its details, as I do not have the hardware and software to test this. If you find it interesting test it youreldf and provide us with he results, it might be interesting.

Hope this heps,

Daniel Chartier

Hello Frisby;

You are right, the presentation in that link skips one very important point.

The section you see on establishing connection with a S7-200 seems pretty straightforward, you can follow it to create a cable between the Delta HMI and the S7-200, and also to setup the communication parameters between the two.

But they stopped the presentation before they showed you the way the HMI talks to and controls the PLC. You have nothing to write in the PLC for exchnges with the HMI, everything is done in the HMI screens. This is very oftent the case with Master-Slave communications, such as this one.

So let's work on a test project:  write a single line of ladder code in the S7-200 (in OB1), in Microwin 4.0, something simple such as this:

In the DOP-B software, create a new screen, place a button with 2 states (ON/OFF) on the screen , seect address M1.0 (from the S7-200). Add a pilot light (a circle with 2 colours, ON/OFF) on the same screen, select address Q0.0 for the pilot light. Download the programs to the S7-200 and  the HMI, respectively. 

Run the HMI program, press the button on the screen, the plot light should light up on the HMI. And if you look at the PLC, the Q0.0 LED should be active, until you press the button on the HMI screen a second time.

Hope this helps,

Daniel Chartier.

HAVE A NICE DAY. 
I PERFORMED PANEL COMMUNICATION WITH PLC, 
BUT IT IS NOT DETECTED BY PLC WHEN I PRESS 
START AND STOP THAT I DETERMINED AS MEMORY BITS.