INFICON BPG402-SP ATM to Ultra-High Vacuum Gauge (Profibus) - Manual (Page 9)

tira47e1 (2005-08) BPG402SPv1.cp
9
The instruction and response are represented in the first two bytes (PKE) of the
parameter channel:
Bit position
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
AK res. Slot
Where: Bits Meaning
15 … 12 AK
Instruction/response signature
11 … 8 Reserved
7 … 0 Define the slot from which data are read or onto which a
value is to be written
In Master
⇒ Slave communication, the AK field contains the instruction signature of
the master.
In Slave
⇒ Master communication, the AK field contains the instruction signature of
the slave.
AK Function
Master
⇒ Slave
(Instruction signature)
AK
normal
Function
Slave
⇒ Master
(Response signature)
AK
error
0 No instruction 0 No response
1 Read parameter value 1
2
11
Transmit parameter value
(word)
Transmit parameter value
(double word)
Transmit parameter value
(byte)
7
1)
2 Write parameter value
(data type: word) 1 Transmit parameter value
(word) 7 1)
3 Write parameter value
(data type: double word) 2 Transmit parameter value
(double word) 7
1)
10 Write parameter value
(data type: byte) 11 Transmit parameter value
(byte) 7
1)
1)
Instruction cannot be executed (error code)
On the left of the table, the instruction signatures of the master are listed according
to their function. On the right of the table, the corresponding normal responses (AK
Normal) and error codes (AK Error) transmitted by the slave are listed.
1) The master transmits an instruction to the slave and repeats that instruction
until it receives a response from the slave.
2) The slave keeps transmitting the response to the instruction until the master
transmits a new instruction.
3) The master marks the end of the first instruction cycle by setting AK to zero.
Only after that, a new instruction/response cycle may be started.
The PWE represents the data element to be transmitted.
If a byte is to be transmitted, that byte has to be in position 8 of the parameter
channel.
Integers are transmitted with bytes 7 and 8. Double integer and float values are
transmitted with bytes 5 … 8.
2.2.1.1 PKE Parameter
Signature Value
Instruction signature
Instruction – response
sequence
2.2.1.2 PWE Parameter
(Process Value)