# Parameter value request

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Example: Requesting the value of the parameter 123 [dec] that has 32 bit data type.

Request identifer (AK) = 1

PNU = 123dec= 0x7B

Therefore: PKE = 0001 0000 0111 1011 = 0x107B

PKW related values in the Output buffer:

Output Buffer
…
PKE | 0x107B
IND | 0x0000
PWE1 | 0x0000
PWE2 | 0x0000
…

The slave (controller) should respond to the PKW telegram with the following telegram in the Input buffer:

Input Buffer
…
PKE | 0xYX7B
IND | 0xXXXX
PWE1 | 0xXXXX
PWE2 | 0xXXXX
…

Y = AK. It can be 1, 2 or 7. (See the Table 1)

Interpretation of the received data:

Example 1:

Input Buffer
…
PKE | 0x207B
IND | 0x0000
PWE1 | 0x0A5C
PWE2 | 0xDD50
…

The Response identifier (AK) = 2 which is “Transfer parameter value (double word)” (see Table 2). That means that the requested parameter value is transferred properly. The Parameter value is 0x0A5CDD50 = 173858128 dec.

Example 2:

Input Buffer
…
PKE | 0x707B
IND | 0x0000
PWE1 | 0x0000
PWE2 | 0x0001
…

Response identifier (AK) = 7 which is “Not possible to process request” (see Table 2). That means that the request is not performed. Therefore there is no valid parameter valid in PWE.

Because the response identifier is 7, there is an additional error code in PWE2. The error code 1 means “No access rights“ (see Table 3). In this case, there are no access rights to read the Parameter value.