VEGA VEGACOM 557 Profibus DP - Manual (Page 31)

VEGACOM 557 Profibus DP 31
Control command 0xCB (DISBUS)
In case of an enquiry with this control command, the measured values are grouped acc. to
DCS indices or channels.
Grouping of measured values acc. to DCS indices or channels
all DCS outputs with index =1
all DCS outputs with index =2
2 Byte
output section
Byte 1 Byte 2
control
command Block no.
0xCB
0x01
...0x20
DP-Master Control command: 0xCB
Block no.: 0x01...0x20
Enquiry of measured value from the Profibus-Master
Example:
Enquiry telegram to VEGACOM 557 (2 Byte):
0xCB 0x01 Block no. 1 is enquired
Answering telegram of VEGACOM 557 (50Byte):
0xCB 0x00 0x01 0xFE 0x00 0x00 0x00 0x00 0x11 0xYY 0x00 0x00 0xHH ...
Control word Reserved PC/DCS value no. 1, VEGAMET no. 1
0xYY = Index-Byte
0xHH = High-Byte measured value
0xLL = Low-Byte measured value
Data image in VEGACOM 557
The division of the individual PC/DCS values into blocks is shown in the following figures.
There are a total of 32 blocks with 8 PC/DCS values each.
The enquiry is made as described before, the only exception is that 0xCC is not used as
control command, but 0xCB. With this type of enquir y, you will initially r eceive the first PC/DCS
output of all VEGAMET connected to the DISBUS, then the second PC/DCS output etc. The
advantage is, that with 2 block enquiries you will receive the PC/DCS output of all 15 VEGA-
MET, whereas with the contr ol command 0xCC, 31 block enquiries ar e necessar y.