14 PROFIBUS-PA communication
The PROFIBUS-PA is a version for process automation based on the widely used
PROFIBUS-DP. The transmission technique conforms with the IEC 61158-2 Standard and the
-
refore fulfills the requirements for the type of protection, intrinsic safety.
PROFIBUS-DP defines two types of masters:
4
Class 1 master exchanges the data with the configured slaves.
4
Class 2 master is used for acyclic data exchange for commissioning and diagnostics
purposes.
14.1 Profile
Basic device functions have been described in profiles by PNO (PROFIBUS user organiza
-
tion) to supplement the EN 50170 standard.
The scope of functions of the Type 3730-4 Positioner is consistent with Profile 3.01 with the
extension “Condensed status and diagnostic messages V1.0”.
14.2 Cyclic data exchange
Cyclically transmitted parameters
The following parameters that are transmitted in cyclic data transfer are marked with an as-
terisk (*) in the parameter lists from page 130 onwards.
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POS_D
Current position of the valve (discrete)
0: Not initialized
1: Closed (x < 0.5 %)
2: Open (x > 99.5 %)
3: Intermediate position
4
RCAS_IN
Setpoint with status: Reference variable w in RCAS mode
Provided by a supervisory host, e.g. PID Block or master class 1. Depending on the mode of
the function block.
Range of values defined in PV_SCALE
4
RCAS_OUT
Setpoint with status: Reference variable w in RCAS mode
Provided to a supervisory host, z. B. PID Block or master class 1. Depending on the mode of
the function block.
Range of values defined in PV_SCALE
86 EB 8384-4 EN
PROFIBUS-PA communication
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