Description
You can establish a connection between PC Access and your S7-1200 PLC. Nevertheless, there are some restrictions to keep in mind.
Note
Although establishing a connection between an S7-1200 PLC and SIMATIC NET OPC is not officially supported by Siemens, this FAQ describes a solution. In the following chapters, you will find a description of how to establish such a connection.
Restrictions
There are certain restrictions to be considered due to the fact that PC Access was originally intended to access an S7-200 PLC:
- Only tags in the data block DB1 of your S7-1200 PLC can be accessed because the S7-200 only had one data block.
- DB1 in your S7-1200 PLC needs to be non-symbolic. Please uncheck the checkbox "Symbolic access only" when creating your DB1 (Figure 01).
Requirements
The following items are the hardware and software requirements:
- S7-1200 PLC
- Ethernet cable
- STEP 7 Basic V10.5
- PC Access V1.0.4.10 (SP4)
Create tags in data block DB1 of your S7-1200 PLC project
To create tags in your S7-1200 PLC follow the instructions below.
| No. |
Create tags in data block DB1 of your S7-1200 PLC project |
| 1. |
Add the data block DB1 to your project
Browse the "project tree" and click on the item "Add new block". Click the button "Data block (DB)". Uncheck the checkbox "Symbolic access only". Click the "OK" button.
Fig.01
|
| 2. |
Allocate the tags in STEP 7 Basic
Double-click DB1. Add the following three tags under "name" and "Data type" and give them an "initial value".
- Item_01: "Byte"
- Item_02: "Int"
- Item_03: "DWord"
Fig.02
Click the item "Save project" in the tool bar. Download the project by clicking the download button in the tool bar. |
| 3. |
Monitor the tags in STEP 7 Basic
To cross-check the tag values, use the watch table function of STEP 7 Basic. Browse the "Project tree" for the item "Add new watch table" and fill in the "Name" and "Address" of the required tags.
In this example, add the following three tags:
- Item_01: "DB1.DBB0"
- Item_02: "DB1.DBW2"
- Item_03: "DB1.DBD4"
Fig.03
|
Table 01
Create a new PC Access project and access tags
Follow these instructions to establish a connection between PC Access and your S7-1200 PLC to access data of your PLC.
| No. |
Create a new PC Access project and access tags |
| 1. |
Create a new project
Browse the menu bar, and select "File > New". A new project will be created.
Fig.04
|
| 2. |
Add a new PLC
Highlight the entry "MicroWin(TCP/IP)" in the "project tree".
Browse the menu bar, and select "Edit > New > PLC". A "NewPLC" object will be added, and the "PLC properties" dialog window of the new PLC opens. Enter the following parameters into the input fields of this window:
- Name: "S7-1200_PLC"
- IP Address: "192.168.0.11" (IP adress of your S7-1200 PLC)
- TSAP Local: "10.00." (TSAP of PC Access)
- TSAP Remote: "03.01." (TSAP of your S7-1200 PLC)
Click the "OK" button.
Fig.05
|
| 3. |
Add a new item
Highlight your S7-1200 PLC in the "project tree". Browse the menu bar, and select "Edit > New > Item". The dialog window "Item properties" opens.
To access data in your S7-1200 PLC, perform the following steps:
- Enter an item name in the "Name:" input field.
- Enter the address of the tag in the "Address:" input field.
- Select the type of data in the "Data Type:" input field.
Additionally, you can restrict the memory address access to "read" only or "write" only.
Click the "OK" button.
Fig.06
Note
Please find a list of the accessible items at the end of this document in the table "accessible tags and items". |
| 4. |
Save the project
Browse the menu bar, and select "File > Save" to save your project.
Fig,07
Note
Anytime you open or edit a PC Access project, you must click the "Save" button to send tag configurations to the server.
Fig.08
|
| 5. |
Monitor items via the Test Client
Highlight the items you want to monitor and and click the "Add current items to test client" button in the tool bar. The selected items will be added to the Test Client.
Fig.09
|
| 6. |
Start the Test Client
Click the "Start Test Client" button in the tool bar. The Test Client will go online and access the designated data.
In the "Value" column, you can see the actual values of the listed items. If you are connected to your S7-1200 PLC, the "Quality" of the item is listed as "Good".
Fig.10
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Table 02
Accessible items
The following table shows all accessible items, including address examples.
| Item |
Address example |
| tags |
"VB0", "VX1.0", "VW2", "VD4" etc. |
| markers |
"MB8", "MX9.2", "MW10", "MD12" etc. |
| inputs |
"I0.0", "AI0" etc. |
| outputs |
"Q1.3", "AQ0" etc. |
Table 03
Required version of PC Access
The required version of PC Access is V1.0.4.10 (SP4) or higher.
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