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messer · Senior Joined: 08 Mar 2012 Posts: 2059 Location: Europe

Hello guys,
I have aproblem with Profibus Communication to an FCI ST98 FlexMASSter Mass Flow Meter from a Siemens PLC

I am attempting to monitor the measured values of an FCI ST98 FlexMASSter Mass Flow Meter with an IM151-8 PN/DP CPU with a 6ES7138-4HA00-0AB0 DP MASTER INTERFACE.
I am able to communicate with the meter using the vendor's DTM and PACTware;
I do not have access to PDM yet .
I was able to monitor the measured values in the HW Config for about 10 minutes.
After cycling power, the meter is now a passive drop and the PLC will not reconnect. The diagnostics of the slave:
"DP slave not ready yet for data exchange, Incorrect parameter message frame, Parameters must be assigned to the DP slave again"
Has anyone used this meter?
The vendor has no experience with Siemens and is convinced that it is my fault or the PLC.
If it worked once, and works with PACTware every time, what I am I missing when trying to use the PLC?
Can I use a communications function to cause a DP slave to return to active mode?

rott · Senior Joined: 23 Aug 2011 Posts: 2266

The ST98 Profibus Flowmeter Process data and Configuration parameters are organized per the Profibus Profile 3 model for Mass Flowmeters.
This model uses the Profibus DS-33 structure for Process data Input under Profibus DPV0 and the Function Blocks concept for the configuration and setup under Profibus DPV1.
The DS-33 structure consists of a maximum of 2 four bytes floating point numbers and a status byte, the two floating point numbers correspond to the Process Flow and the Process Totalizer values.
The order of transmission and the selection of this parameters is done during parameterization with a Class 1 master configuration tool utilizing the ST98 GSD File.
The setup and configuration of the ST98 Flowmeter uses the functions blocks defined in the Profibus Profile 3 Standard for Mass Flowmeters.
The configuration structure is organized into 3 major blocks called “Physical Block”, “AI Block” and the “Transducer Block” The Physical Block contains dispozitiv identification information, The AI Block Contains the setup of the Flow and Totalizer data, with Alarm settings and scaling parameters.
The Transducer Block contains the selection of Flow units, Pipe or Duct dimensions, and other setup parameters used by the ST98 Flowmeter.

Read carefully the manual and use DPV0 profile for Profibus.
http://www.fluidcomponents.com/Industrial/Library/manuals/Flowmeters/ST98,%20ST98L%20Guides%20&%20Manuals/ST98%20FlexMaster%20Profibus%20 (06EN003376-).pdf