YASKAWA CP 341 Manual page 82

Communication protocols
Modbus > Modbus Slave - Function codes
Calculation
bit_number
Example
start_addr
hex decimal
0000h 0
0001h 1
01F1h 497
0400h 1024
0401h 1025
07DAh 2010
82
n Byte address = ((start_addr - Param-start-address) / 8) + PLC-area
When accessing bit memories respectively inputs of the CPU, the remaining Rest-bit-
number is calculated and used to address the relevant bit within the bit memory area
respectively the input area.
Rest-bit-number = (start_addr - Param-start-address) % 8 [Modulo 8]
n Values between 1 and 2040 are permitted as bit_number. This number of bits are
read.
Conversion Modbus addressing for FC 02
"Modbus address in the transmission message"
Param-start-address
from 0 ... 1023
from 1024 ... 2047
Access
Memory
Memory
Memory
Input (1024 - 1024)
Input (1025 - 1024)
Input (2010 - 1024)
Calculation
(0 - 0) / 8
(1 - 0) / 8
(497 - 0) / 8
/ 8
/ 8
/ 8
VIPA System 300S
"SIMATIC memory area"
PLC-area
Memory commence at M 1000.0
Inputs commence at I 100.0
+1000 →
+1000 →
+1000 →
+100 →
+100 →
+100 →
HB130 | CP | 341-1CH01 | en | 18-40
Area in
PLC
M 1000.0
M 1000.1
M 1062.1
I 100.0
I 100.1
I 223.2