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45
TASK 6 (Modbus TCP Option)
M
ODBUS
TCP C
ONFIGURATION
Enable Modbus TCP Protocol
The internal web page utility can be used to change the communications protocol used by the RBE2-8. This is
typically done while setting the IP address. Specifically, follow the steps in section 2.2b,
Modbus Addressing
The register addresses used in this manual are the
Modbus logical reference numbers
†
, which are unsigned
integers starting at zero. This is often called
zero based
addressing. In this scheme, the first register is given
an address of zero. This is the actual addressing scheme used in the Modbus packets.
Another common addressing scheme is
one based
or
data model
addressing. In this scheme, the register’s
number is used as its address, so the first register, Register 1 in the data model, has an address of 1.
Modbus Table Mapping
The Discrete Input and Input Register tables in the Modbus data model map to the same physical memory
locations in the RBE2-8 units.
These registers hold data that is reported from the RBE2-8 to the host controller.
Addresses for these registers and inputs start at 0 in zero based addressing.
As examples:
Discrete Input 0 is the same memory location as bit 0 of the first Input Register.
Register address 1, the second register, contains Discrete Inputs 16 through 31.
The Coil and Holding Register tables in the Modbus data model map to the same physical memory locations
in the RBE2-8 relay boards.
These registers hold data that is from the host controller to the unit.
Addresses for these registers start at 1024 in zero based addressing. Coil addresses start at 16,384 in
zero based addressing (1024*16).
As examples:
Coil 16384 is the same memory location as bit 0 of the first Holding Register.
Register address 1025, the address of the second Holding Register, contains Discrete Outputs 16,400
through 16,415 in zero based addressing.
Host Addressing
Your host controller may not use these basic addressing schemes for communicating over a Modbus connec-
tion. For example, Modicon controllers use addresses starting at 30000 for Input Registers and addresses
starting at 40000 for Holding Registers. GE hosts internally use their %R memory for Holding Registers and
%AI memory for Input Registers.
If this is the case, you will define a mapping between your host controller’s addressing scheme and the zero
based Modbus TCP addresses when you add the RBE2-8 to your host controller. Refer to your host control-
ler’s documentation for information on how to accomplish this.
This chapter tell you how the I/O words used by an AMCI RBE2-8 are mapped to
the Modbus I/O registers.
† MODBUS Application Protocol Specification V1.1b3, section 4.3: MODBUS Data model.
www.modbus.org
Содержание RBE2-8
Страница 14: ...RBE2 8 INTRODUCTION RBE2 8 User Manual ADVANCED MICRO CONTROLS INC 14 Notes ...
Страница 30: ...PROTOCOL SPECIFIC INFORMATION RBE2 8 User Manual ADVANCED MICRO CONTROLS INC 30 Notes ...
Страница 48: ...MODBUS TCP CONFIGURATION RBE2 8 User Manual ADVANCED MICRO CONTROLS INC 48 Notes ...
Страница 54: ...LEADERS IN ADVANCED CONTROL PRODUCTS ADVANCED MICRO CONTROLS INC ...