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4. Software Implementation of the Gateway
4.2.10. Description of Services Assigned to Gateway Inputs/Outputs
Managing the downstream Modbus network: Refer to chapter 5.3 Diagnostic Only, page 41, for a detailed
description of that service, and to chapter 11.2 LUFP7 Gateway Initialization and Diagnostics, page 98, for an
advanced sample use. In the case of the gateway’s default configuration, under AbcConf, the “Control/Status
Byte” field of the “ABC” element is equal to “Enabled but no startup lock.”
Periodic communications (inputs): The value of each of the 8 words for this service corresponds to teh value
of the status register of a TeSys U motor starter (register located at address 455).
Periodic communications (outputs): The value of each of the 8 words for this service corresponds to the value
to be sent to the command register of a TeSys U motor starter (register located at address 704).
Refer to chapter 11.3 Controlling and Supervising the 8 TeSys U Motor Starters, page 100, for a sample use of
these "periodic communications" services.
Aperiodic communications: Refer to chapter 11.4 Reading and Writing any TeSys U Motor Starter Parameter,
page 101, for a simple example of these "aperiodic communications".
These aperiodic communications services offer functions similar to those of “parameter area PKW” which can be
found on certain Schneider Electric products, such as some ATV drives.
• Sample reading of a motor starter parameter:
Reading of the 1st fault register (address = 452 = 16#01C4) on TeSys U motor starter no. 5.
The initial values of %QW4.0.15 and %IW4.0.15 are equal to 16#0613.
The result of the reading is 16#0002 (magnetic fault).
Output Value Meaning (MSB + LSB) Input Value Meaning (MSB + LSB)
%QW4.0.90
16#0503
Slave no. + Function no. %IW4.0.90
16#0005
(not used) + Slave no.
%QW4.0.10
16#01C4
Parameter address %IW4.0.10
16#0302
Slave no. + Number of bytes
%QW4.0.11
16#0001
Number of parameters %IW4.0.11
16#0002
Value read
%QW4.0.15
16#0713
“Trigger byte” for the query (PF)
%IW4.0.15
16#0713
“Trigger byte” for the response (PF)
• Sample writing of a motor starter parameter:
Writing of the 2nd command register (address = 705 = 16#02C1) on TeSys U motor starter no. 7 at the value
16#0006 (clear statistics + reset thermal memory).
The initial values of %QW4.0.15 and %IW4.0.15 are equal to 16#0713.
The result of the writing is a command echo, that is to say that the values of the “address parameter” and
“value to be written” fields are identical in both the query and the response.
Output Value Meaning (MSB + LSB) Input Value Meaning (MSB + LSB)
%QW4.0.12
16#0706
Slave no. + Function no. %IW4.0.12
16#0706
Slave no. + Function no.
%QW4.0.13
16#02C1
Parameter address %IW4.0.13
16#02C1
Parameter address
%QW4.0.14
16#0006
Value to be written %IW4.0.14
16#0006
Written value
%QW4.0.15
16#0714
“Trigger byte” for the query (PF) %IW4.0.15
16#0714
“Trigger byte” for the response (PF)
Avoid writing incorrect values in outputs which correspond to the aperiodic communication
services described above, as they would lead to the transmission of an incoherent Modbus
frame. It is therefore up to the Profibus-DP master PLC application to manage them.
In addition, do not ever use these services in “Broadcast” mode (Modbus address = 0).