How can you read out the identification data (the serial number of the MMC, for example) with the SFC 51 in STEP 7 V5.5?
With the SFC 51 "RDSYSST" (read system status) you can read out system status lists or excerpts of system status lists. More detailed information about parameterizing the SFC 51 and about error evaluation is available in the STEP 7 Online Help. For this you mark the SFC 51 in the SIMATIC Manager and press the "F1" key.
You need the following parameterization in order to read out the serial number of the MMC:
- SSL ID W#16#011C "Identification of a component"
- Index W#16#0008 "Serial number of the memory card"
Fig. 01 shows the call and parameters of the SFC 51 "RDSYSST".
The table below specifies which other identification data can be read out depending on the CPU type and firmware version. For this you use SFC 51 and SSL ID W#16#011C.
|W#16#0001||Name of automation system||Firmware version V2.2 onwards||Yes|
|W#16#0002||Name of CPU||Firmware version V2.2 onwards||Yes|
|W#16#0003||Facility ID of CPU||Firmware version V2.2 onwards||Yes|
|W#16#0004||Copyright entry||Firmware version V2.2 onwards||Yes|
|W#16#0005||Serial number of CPU||Firmware version V2.2 onwards||As from MLFB 6ES741x-xxx04-0AB0|
|W#16#0006||Reserved for operating system||-||-|
|W#16#0007||CPU type name||-||Yes|
|W#16#0008||Serial number of the MMC||Firmware version V2.0 onwards
(CPU317: as from firmware version V2.1)
|Firmware version V5 onwards|
Notes on the output of SFC51 with a Field PG
When you read out the serial number of an MMC with SFC51 on the Field PG, the output data of the SFC51 is different to the serial number of the MMC. The reason for this system-specific behavior is that the digits of the hexadecimal code have been resorted through processing of the SFC51. For the output of a serial number, 1342498713, for example, with the SFC51 you get the value 99E70450Hex .
The table below explains how the SFC51 output is made after resorting of the digits.
|Serial number of the MMC:||1342498713|
|Hex code of the serial number:||5||0||0||4||E||7||9||9|
|Designation of the digits:||a1||a2||b1||b2||c1||c2||d1||d2|
|Digits are resorted with SFC51:||d1||d2||c1||c2||b1||b2||a1||a2|
|Display with SFC 51:||9||9||E||7||0||4||5||0|
There is a unique serial number saved on the memory cards of S7-400 version V5 onwards and the MC serial number can be read out using any SIMATIC S7-400 CPU with firmware V5.0 onwards.
The following documents contain further information about the memory cards and the system status list.
- For MC:
device manual "S7-400 Automation System, CPU Specifications"
(Entry ID: 23904550),
- For SSL:
reference manual "System and Standard Functions for S7-300/400"
(Entry ID: 1214574).
Memory card, RAM card, FLASH card, FEPROM card, System status list
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