Automation Direct D2-DCM, Руководство пользователя

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C–3
C–3
Using the D2–DCM with MODBUS
Data Communications Module, 2nd Edition, 2/03
The host software package reads or writes information by sending a MODBUS function code
to the D2–DCM. The following table provides a description of the MODBUS function codes
supported by the D2–DCM.
MODBUS Code Function DL205 Data Types
Available
01 Read a group of coils Y, CR, T, CT
02 Read a group of inputs X, SP
05 Set / Reset a single coil Y, CR, T, CT
15 Set / Reset a group of coils Y, CR, T, CT
03, 04 Read a value from one or
more registers V
06 Write a value into a single
register V
16 Write a value into a group
of registers V
NOTE: The maximum MODBUS secondary address supported by the D2–DCM is 60 (5A
hex).
You are probably accustomed to seeing data types like X input, Y output, C control relay, V
memory data registers, etc. for the various types of memory in a DL205 system. For example,
if you need to know the status of Y12, then you ask for Y12. MODBUS does not use these
same data types, so you have to determine which MODBUS data type corresponds to the
PLC memory location that you need. The following table will help.
DL205 Memory Type Quantity 1
(Decimal)
PLC Range
(Octal)
Corresponding
MODBUS
Data Type
Inputs (X) 320 X0 – X477 Input
Special Relays (SP) 144 SP0 – SP137
SP540 – SP617 Input
Outputs (Y) 320 Y0 – Y477 Coil
Control Relays (CR) 256 C0 – C377 Coil
Timer Contacts (T) 128 T0 – T177 Coil
Counter Contacts (CT) 128 CT0 – CT177 Coil
Stage Status Bits (S) 512 S0 – S777 Coil
Timer Current Values (V) 128 V0 – V177 Input Register
Counter Current Value (V) 128 V1000 – V1177 Input Register
V Memory, user data (V) 1024 V2000 – V3777 Holding Register
V Memory, user data (V)
Non–volatile 256 V4000 – V4377 Holding Register
V Memory, system (V) 106 V7620 – V7737
V7746 – V7777 Holding Register
MODBUS Function
Codes Supported
MODBUS Data Types
Supported