User`s manual

15
FX3U Series Programmable Controllers
User’s Manual - MODBUS Serial Communication Edition
2 Specifications
2.2 Link Time
1
Outline
2
Specifications
3
System Configuration
4
Wiring
5
Communication Setup
6
Related Devices and Comm. Status
7
MODBUS Standard Commands
8
Master Specification
9
Slave Specification
10
Creating Programs
Example Link Time Calculations:
Master processing time (Tm)
D8411 = 5ms
Max Scan Time = 5ms
Command = Read Holding Registers 0-9 (Command Code 0x03)
Frame Mode = RTU Mode
Bytes in Request = 8bytes (1byte Address, 5byte Frame, 2byte CRC)
Bytes in Response = 25bytes (1byte Address Echo, 22byte Frame, 2byte CRC)
Character Length = 10bits (1bit Start, 8bit Data Length, 0bit Parity, 1bit Stop)
Baud Rate = 19.2Kbps
Slave Delay = 10ms
T4 = 5ms
T6 ≈ 1ms
T8 = 10ms
T5 = 1ms + 5.2ms + 10ms + 14.0ms + 2.8ms = 33ms
T3 ≈ 1ms
Tm = 5ms + 35ms + 1ms = 41ms
Slave processing time (Ts)
Command = Read Holding Registers 0-9 (Command Code 0x03)
Frame Mode = RTU Mode
Bytes in Request = 8bytes (1byte Address, 5byte Frame, 2byte CRC)
Bytes in Response = 25bytes (1byte Address Echo, 22byte Frame, 2byte CRC)
Character Length = 10bits (1bit Start, 8bit Data Length, 0bit Parity, 1bit Stop)
Baud Rate = 19.2Kbps
D8411 = 5ms
Max Scan Time = 5ms
T15 = 5ms
T11 = 5.2ms + 5ms + 5ms = 15.2ms
T12 ≈ 1ms
Ts = 15.2ms + 1ms + 14.0ms = 30.2ms
()
10ms5ms115ms*1
5ms
5ms
INTT1 =+=+=
*
5.2ms1ms
*
19200bps
10bits*RequestinBytes8
T7
≈
+=
1000 (ms)
14.0ms1ms
*
19200bps
10bits*ResponseinBytes25
T9
≈
+=
1000 (ms)
2.8ms1ms
*
19200bps
10bits*Characters3.5
T10
≈
+=
1000 (ms)
()
35ms5ms*16
5ms
*1
5ms
33ms
INTT2 =+=+=
5.2ms1ms*
19200bps
10bits*RequestinBytes8
T14 ≈ +=
1000 (ms)
14.0ms1ms*
19200bps
10bits*ResponseinBytes25
T13 ≈ +=
1000 (ms)