CPE CPE Device Management & GSD Files 2 — Questions and Answers
Question 1: In PROFIBUS DP, what is the function of the 'Ident_Number' field in a GSD file?
- It assigns the slave a unique network address
- It is a vendor-assigned unique identifier used by the master to verify a correct slave type is present (Correct answer)
- It specifies the firmware version of the device
- It defines the maximum input data length
Correct answer: It is a vendor-assigned unique identifier used by the master to verify a correct slave type is present
The Ident_Number is a two-byte vendor-specific code registered with PROFIBUS International, used by the master to confirm device identity during configuration.
Question 2: Which PROFIBUS DP diagnostic byte contains the 'Station Not Ready' bit that indicates a slave is not yet ready for data exchange?
- Status Byte 1 (Correct answer)
- Status Byte 2
- Status Byte 3
- Extended Diag Byte
Correct answer: Status Byte 1
Status Byte 1 of the standard 6-byte diagnostic response contains bits including Station Non Existent, Station Not Ready, and Configuration Fault.
Question 3: A PROFIBUS slave device sends extended diagnostic data. Where in the diagnostic telegram does device-specific extended diagnostic data begin?
- Byte 1
- Byte 4
- Byte 7 (Correct answer)
- Byte 10
Correct answer: Byte 7
The first 6 bytes of a PROFIBUS DP diagnostic telegram are standardized header bytes; device-specific extended diagnostic data starts at byte 7.
Question 4: What is the maximum length of the extended diagnostic data block in a PROFIBUS DP slave response?
- 16 bytes
- 32 bytes
- 58 bytes (Correct answer)
- 244 bytes
Correct answer: 58 bytes
The total diagnostic response including the 6 standard bytes must not exceed 244 bytes, leaving a maximum of 238 bytes for extended diagnostics, but the standard caps the extended block at 58 bytes for DP-V0.
Question 5: In a PROFIBUS PA device, what does the Physical Device Tag (PD_TAG) represent?
- The device's PROFIBUS station address
- A user-assigned alphanumeric name stored in the device that identifies it in the plant (Correct answer)
- The manufacturer's catalog number
- The device's profile class identifier
Correct answer: A user-assigned alphanumeric name stored in the device that identifies it in the plant
The PD_TAG is a configurable 32-character string stored in the device used to identify it by plant tag name, independent of its network address.
Question 6: Which PROFIBUS PA device parameter block contains the process value and its status for transmission to the DCS?
- Transducer Block
- Function Block (AI/AO) (Correct answer)
- Physical Block
- Resource Block
Correct answer: Function Block (AI/AO)
Function Blocks (such as Analog Input or Analog Output) hold the process value (PV) and its quality status that are exchanged cyclically with the host.
CPE CPE Device Management & GSD Files 2
In PROFIBUS DP, what is the function of the 'Ident_Number' field in a GSD file?