Function Code 04 (Read Input Register); Function Code 06 (Preset Single Register); Function Code 15 (Force Multiple Coils) - Samson Trovis 6400 Mounting And Operating Instructions

Functions supported by the Modbus protocol

9.5.5. Function code 04 (Read Input Register)

With this function code, the current status of the analog inputs in 1, in 2, in 3 and in 4 can be
read directly at the input of the slave, no matter whether the respective analog input has been
assigned the variable X, W
For the query from the central control station and response from the process control station, see
Read Holding Register (Function code 03).

9.5.6. Function code 06 (Preset Single Register)

With this function code, analog values, such as the value of the set point (reference variable)
or K can be modified.
P
Example: Write holding register 106.
This is the value of the set point (reference variable) which can be written serially. The process
control station has the station address 18 and operates as a fixed set point controller. A set
point (reference variable) value of 10.0 is to be transmitted from the central control station to
the process control station.
Query from the central control station
Address Function
12 06
Response from the process control station
Address Function
12 06

9.5.7. Function code 15 (Force Multiple Coils)

This function code allows modifying the status of multiple coils.
Example: 10 coils, starting at address 20 (13
the address 17. For this purpose, two bytes are transmitted.
Byte 1 = CD =
H
Coil no.
Byte 2 = 00 =
H
Coil no.
In this example, "1" is written to coils 27, 26, 23, 22 and 20; "0" is written to the remaining
coils.
Query from the central control station
Address Function Coil address
high
11 0F 00
64
, Z or Y
EX ACTUAT
Holding register no.
high low
00 6A
Holding register no.
high low
00 6A
1 1 0
27 26 25
0 0 0
0 0 0
Quant. of coils Byte count
low high low
13 00 0A
.
Value in register 35
high low
00 64
Value in register 35
high low
00 64
), are written to the process control station with
H
0 1
24 23
0 0
0 0
Data coil
field
20 to 27
02 CD
Interface RS-485
Checksum
low high
AA 9E
Checksum
low high
AA 9E
1 0 1
22 21 20
0 0 0
0 29 28
Data coil CRC
28 to 29 low high
00 7E CB