The Operator Panel sporadically displays the error message: "$044 Transfer error ... "
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Entry
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Associated product(s)
QUESTION:
What is the meaning of the error message "$044 Transfer error ...
" that is displayed sporadically on the OP?
ANSWER:
During communication with the controller the error message "$044
Transfer error ... " that is displayed sporadically on the OP.
This message is output when the connection between the OP and the
controller is defective. Possible causes can be faults in the
transfer segment (bus faults on MPI/ PROFIBUS) or also wrongly set
interface parameters on the Operator Panel or on the
controller.
Please check the following points to clear this fault:
- Connection of the OP to the controller
To ensure correct connection of the OP to the controller we recommend configuring using the ProTool option "STEP 7 integrated". This means that your ProTool configuration is a component of the STEP 7 project. If you connect the OP correctly to the available MPI or PROFIBUS subnetwork of the CPU (ProTool: Entry "Controller" see Fig. 1), the OP is inserted as bus node and taken into account in the calculation of the bus times in NetPro (see Fig. 2).
Fig. 1: Connection in ProTool
Fig. 2: Bus nodes in NetPro
Note:
If it is not possible to integrate the OP project in STEP 7, you
can change the bus times as "user defined" (see Properties of
PROFIBUS). In this case you increase the target rotation time (TRT)
so that the CPU can communicate with the OP.
- Observation of PROFIBUS installation guidelines
Detailed information on the installation guidelines for PROFIBUS and MPI subnetworks is available in the manual "SIMATIC S7-400 and M7-400 Programmable Controllers Hardware and Installation", Chapter 5 Networking in Entry ID: 1117849.
- Observation of EMC guidelines
Please strictly observe the EMC (electromagnetic compatibility) guidelines when installing.
- Number of OP connections of the CPU
Check the number of connection resources of your CPU. Refer here to the technical data of the CPU.
- Defective OP interface
In rare cases it might also happen that the interface on the OP is defective. In this event replace the OP.
Keywords:
OP7, OP17, OP27, OP37, TP27, TP37, Bus
faults
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