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Entry type: FAQ Entry ID: 81715524, Entry date: 01/28/2014
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How can you read out all the measured values of the Energy Meter at once?

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Description
There are several options for reading out the measured values of the energy meter:

  • Cyclic reading via the IO data.
  • Acyclic reading via the data record 143 or 142.

The FAQ response describes how to read out all the measured values via the data 142.

Requirements
If the "Energy meter gate" is enabled, the energy meters only count when the "Energy meter gate opened" bit in the output data (Offset 1.6) is also set to "1".

Instructions
The following table describes how to read out acyclically the measured values of the energy meter via the data record 142.
 

No. Procedure
1 Create a data type with an identical structure to the data record 142. The sample project already contains such a UDT. Detailed information about the structure of data record 142 is available in the PDF in the download area of the FAQ response.
2 Read out the data record using the SFB 52 "RDREC" from the Energy Meter.

The input parameters of the SFB must be configured as follows:

  • REQ: A new read job is triggered if REQ = TRUE.

  • ID: You get the ID from the HWCN of STEP 7. The first input address is the ID. The ID must be specified in hexadecimal form.

Example: 16#0100


Fig. 01

  • INDEX: The data record number: 142.

  • MLEN: Maximum length of the data record: 210.

  • RECORD: A pointer to the data area in the CPU that contains the data record 142.

The data record transmission is completed when the BUSY output parameter has the value FALSE.

Note
If you want to write to or read from multiple energy meter modules at the same time, then pay attention to the maximum number of active jobs of the communication with SFB52/SFB53 (Entry ID 15364459)!

3  All the measured values listed in the "Measured Variables" section are thus transferred to the CPU and can be evaluated in the user program.

Note
The measured values of the energy meter are available partly in the DOUBLE data format (64-bit floating-point number). This corresponds to the LReal data format in the S7-1500. The FAQ response in Entry ID 56600676 describes how you convert your values from the DOUBLE format for other CPUs. The FAQ response also provides the "LREAL2DINT" block.

Table 01

Download
The *.zip file includes the "EnergyMeter_allData.zip" project.
Copy the "EnergyMeter_allData.zip" file into a separate directory and then start the file with a double-click. You can then use STEP 7 V12 to open and process the extracted project data.

EnergyMeter_allData.zip ( 1137 KB )

The PDF document contains the structure of the data record 142.

DS142_allData_e.pdf ( 36 KB )

Further Information
More FAQ responses about the Energy Meter IO module are available:

  • Manual:
    SIMATIC ET 200SP Analog Input Manual AI Energy Meter ST
    (Entry ID 73098696)
  • FAQ:
    What should you watch out for when setting up and configuring an ET 200SP with an Energy Meter?
    (Entry ID: 81800892)
  • FAQ:
    How do you find out the current measuring value from the IO data of the energy meter?
    (Entry ID: 81714201)
  • FAQ:
    How do you reset the Energy Meter?
    (Entry ID: 81715807)
  • FAQ:
    How do you select a current transformer for the ET 200SP Energy Meter and how do you connect it to the module?
    (Entry ID: 85477190)

Creation environment
The screens and downloads in this FAQ response were created with STEP 7 V12 SP1.

Security information
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https://www.siemens.com/cybersecurity#Ouraspiration.