INFICON BCG450-SP ATM to Ultra-High Vacuum Triple Gauge (Profibus) - Manual (Page 7)

tira41e1 (2005-06) BCG450SPv1.cp
7
2 Data Exchange Mode
The reading and writing operations defined in Profibus are based on a slot index
address scheme. In BCG450-SP, all device functions are organized in the following
blocks:
• A device block describing all organizational parameters of the gauge (serial
number, manufacturer, software version, …)
• An Analog Sensor Function Block describing the function of the pressure pres-
entation
• An Analog Sensor Transducer Block describing the physical interface between
the gauge and the process (emission current, ion current, …).
The block model is described in detail in section "Block Model".
Each block is assigned to a separate slot. The exact assignment
Block
⇒ Slot ⇒ Index is described in section "Block Model". The Device Block is
assigned to Slot 0, the transducer and functional blocks to Slot 1.
Device
Block
Block_1 Block_2 Block_3
0 1 2 3
0
254
Index
There are 254 indices per slot. The indices can have a width of 255 bytes. All val-
ues that can be accessed via Profibus have to be mirrored to one of these slots/
indices.
The parameters are generally numbered in ascending order, starting with index 16.
Services such as "Degas On" or "Full scale" are numbered in descending order,
starting with index 15.
2.1 Acyclic Data Trans-
mission with Profibus
DPV1 Functionality
Block, slot and
index assignment