Functions Of Drivedsb - Honeywell Experion PKS User Manual

7 DEVICE SUPPORT BLOCK (DSB)
If the C300 is controlling the drive (there exists a loaded PIOMB that refers to this DRIVEDSB) then update
rate for the PKW parameters in the display is faster. As a rough estimate, assuming ideal conditions, you
could expect to have all of the PKW parameter refresh their values in a time period of approximately 5
seconds.
However, if there are no PIOMBs loaded and connected to the DRIVEDSB, the rate at which the PKW
parameters refresh their values become very slow. The parameter values in the display may refresh their values
in a time period of around 30 through 60 seconds for the 32 channels.
Supported data transfer types
The DRIVEDSB supports the PROFIdrive cyclic and acyclic (through the PKW area) data transfer of the PPO
types.
• PROFIdrive cyclic data transfer - The PROFIdrive specification V2 defines the cyclic data transfer for fast
data transfer at equidistant time intervals.
• PROFIdrive acyclic data transfer - The PKW area is used to access acyclic parameters through the cyclic
process data communication path (pseudo acyclic data transfer using DP-V0). The output data defines
parameter ID and sub-index and value for parameter write. The input area has value for parameter that was
last requested or status of the parameter write.
Tip
For more information on the PROFIdrive technology, refer to the PROFIBUS website.
Related topics
"Device Support Block (DSB) overview" on page 112
"CEAG Device Support Block (CEAGDSB)" on page 129
"Generic Device Support Blocks (GENPADSB and GENPAGWDSB) for PA devices" on page 122
"Siemens AS-i Link Device Support Block (Siemens DP/AS-i-Link DSB)" on page 134
"Siemens ET200M Device Support Block (Siemens ET200M DSB)" on page 138
"Turck Excom Device Support Block (Turck Excom DSB)" on page 142
"Generic Device Support Blocks (GENDSB and GENIODSB)" on page 120

7.6.1 Functions of DRIVEDSB

Function
• Integrates the PROFIBUS DP slave devices to Experion.
• Reads data from field devices and writes output into field devices depending on whether the I/O module is
an input module or an output module.
• Updates channel status and send notification based on the channel status.
• Receives data from PIOMB and sends it to the device, if the PDC is connected to a PIOMB.
• Updates the PDC states.
Data Processing
You can change the channel output values directly through the PDC tab. When you change the values through
the PDC tab, the values are updated in the DSB and then periodically sent out over the PROFIBUS. However,
when using control word bits, you cannot assume that the control word bits will be sent to the device at once.
This is because control word bits must be set in a specific order or a group. Also, the application engineers must
ensure that any control bits which are dependent on each other must be logically tied together by the control
strategy. This means that they must be contained in the same Control Module.
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