Festo 174335, Electronic Manual

Page: 116 / 184

4. Commissioning
4-50
Festo P.BE-VIFB13-03-EN en 0003c
Request diagnostic information
The diagnostic data are requested by the valve terminal via
the function
Slave_Diag .
A description of this function can be found in Chapter 5, sec-
tion: Diagnosis via PROFIBUS-DP.
Cyclic exchange of data
The cyclic exchange of user data is accomplished with the
function
Data_Exchange .
The output data for valve terminals is transmitted with this
function as an octet string of length x.
The octet string length is based on the number of identifier
bytes.
Please note
With the function Data_Exchange, the valve terminal ex-
pects the output information for the valves and electric
outputs.
The entry information + the status bits are sent as a reply
telegram to the master.
Due to the modular character of the valve terminal, the
lengths of the user data telegrams can differ.
Summary of parameters (Data_Exchange):
Octet 1: I/O data byte_1
Bit 0: Input/output x*)
Bit 1: Input/output x+1
. . .
Bit 7: Input/output x+7
Octet 2: I/O data byte_2
Bit 0: Input/output x+8
Bit 1: Input/output x+9
. . .
Bit 7: Input/output x+15