Modbus Rtu Slave Communication - IDEC FC6A-C16K1CE Communications Manual

6: M C
ODBUS OMMUNICATION

Modbus RTU Slave Communication

Modbus slave communication can be configured by selecting Modbus RTU Slave for Port 1, Port 2 and Port 3 in the WindLDR
Function Area Settings. When a Modbus RTU slave receives a request from the Modbus RTU master, the Modbus RTU slave
reads or writes data according to the request. The request is processed at the END processing of the user program.
Modbus RTU slaves do not reply to the Modbus RTU master for the broadcast requests.
Modbus RTU Slave Communication Specifications
Item
Baud Rate (bps)
Data Bits
Stop bits
Parity
Slave Number
Timeout between Characters
Timeout between Frames
*1 When timeout occurs, the FC6A Series MicroSmart discards the received data and waits for the first frame of the next valid communication.
*2 For communication at 19,200 bps or higher, the timeout between characters needs to be a minimum of 0.75 ms.
*3 For communication at 19,200 bps or higher, the timeout between frames needs to be a minimum of 1.75 ms.
Map of Slave Addresses for Modbus RTU Slaves
Modbus Device Name
Coil
(000000 and above)
Input Relay
(100000 and above)
Input Register
(300000 and above)
Holding Register
(400000 and above)
*1 Addresses generally used for Modbus communication. "Calculating Modbus Addresses for FC6A Series MicroSmart Devices" on page 6-9 shows
the method to calculate slave addresses from FC6A Series MicroSmart devices.
*2 These 4-digit addresses are used in the communication frame. To calculate the address used in communication frame, extract lower 5 digits of
the Modbus address, subtract 1 from the value, and convert the result into hexadecimal.
*3 Access within the device range for the FC6A Series MicroSmart type used.
6-8
*1
*1
Modbus Address
*1
Map (Decimal)
000001 - 000504 0000 - 01F7
000701 - 000956 02BC - 03BB
001001 - 003048 03E8 - 0BE7
003049 - 007400 0BE8 - 1CE7
009001 - 009256 2328 - 2427
011001 - 017000 2AF8 - 4267
100001 - 100504 0000 - 01F7
101001 - 101256 03E8 - 04E7
101501 - 101756 05DC - 06DB
102001 - 102768 07D0 - 0ACF
104001 - 104256 0FA0 - 109F
300001 - 300256 0000 - 00FF
300501 - 300756 01F4 - 02F3
302001 - 302768 07D0 - 0ACF
304001 - 304256 0AF0 - 10A0
400001 - 408000 0000 - 1F3F
408001 - 408500 1F40 - 2133
409001 - 409256 2328 - 2427
409501 - 409756 251C - 261B
410001 - 456000 2710 - DABF
462001 - 462768 F230 - F52F
464001 - 464256 FA00 - FAFF
FC6A S M S A
ERIES ICRO MART
9,600, 19,200, 38,400, 57,600, 115,200
8 bits (fixed)
1, 2 bits
Odd, even, none
Constant 1 to 247
Set the special data register values between 1 and 247
Port 1: D8100
Data register
Port 2: D8102
Port 3: D8103
*2
1.5 characters minimum
*3
3.5 characters minimum
Communication
FC6A Series MicroSmart Device
*2
Frame Address
Q0 - Q627
R000 - R255
M0000 - M2557
M2560 - M7997
M8000 - M8317
M10000 - M17497
I0 - I627
T000 - T255 (timer contact)
C000 - C255 (counter contact)
T256 - T1023 (timer contact)
C256 - C511 (counter contact)
T000 - T255 (timer current value)
C000 - C255 (counter current value)
T256 - T1023 (timer current value)
C256 - C511 (counter current value)
D0000 - D7999
D8000 - D8499
T000 - T255 (timer preset value)
C000 - C255 (counter preset value)
D10000 - D55999
T256 - T1023 (timer preset value)
C256 - C511 (counter preset value)
- -O T C
LL IN NE YPE OMMUNICATION
Description
*3
M FC9Y-B1730
ANUAL
Applicable
Function Code
1, 5, 15
2
4
3,6,16
3
3,6,16
3