YASKAWA CP 341 Manual page 89

VIPA System 300S
6.4.8.8 FC 15 - Force Multiple Coils
Request message
ADDR FUNC
start_addr
Calculation
quantity
byte_count n
n-Data
HB130 | CP | 341-1CH01 | en | 18-40
This function enables the Modbus master to write several bits to the output area of the
CPU.
Please consider as soon as you want to access an area by writing, you
have to write enable the corresponding area by the protocol parameters
with the dialog "Limits".
start_addr quantity
Reply message
ADDR FUNC
n The Modbus bit address start_addr contains the start of the area of the CPU, which is
be accessed.
n The corresponding address allocation of the CPU memory area are established by
the properties of "FC 01, 05, 15" in the parameterization of the CP.
– Here the "Modbus address in transmission message" briefly Param-start-address
may be assigned to a "SIMATIC memory area" briefly PLC-area.
n Byte address = ((start_addr - Param-start-address) / 8) + PLC-area
n When accessing bit memories respectively outputs of the CPU, the remaining Rest-
bit-number is calculated and used to address the relevant bit within the bit memory
area respectively the output area.
– Rest-bit-number = (start_addr - Param-start-address) % 8 [Modulo 8]
Each value between 1 and 2040 is valid as quantity (number of bits).
byte_count n (byte counter) is formed automatically due to the bit number.
n-Data contains the bit status (any values).
Communication protocols
Modbus > Modbus Slave - Function codes
byte_count n n-Data
start_addr quantity
CRC
CRC
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