Bender B95061094, Руководство по установке

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Modbus TCP server
30 CP9xx-Kit_D00399_00_M_XXEN/07.2019
5.2.3 Modbus examples to read out data
Example: Reading out from ATICS channel 1 (voltage line 1)
CP9… has address 1 in subsystem 1. ATICS channel 1 of internal address 3 is to be read out. The content is the
voltage of line 1 as floating point value.
Modbus request: 00 01 00 00 00 06 01 04 03 10 00 02
00 01 Transaction ID (is generated automatically)
00 00 Protocol ID
00 06 Length
01 Unit ID (subsystem 1)
04 Modbus function code 0x 04 (read input registers)
03 10 Start register
(Register address at which the value in the memory image appears: 784 = 0x 03 10)
00 02 Length of the data (words)
Response: 00 01 00 00 00 06 01 04 04 01 00 43 63 00 00
00 01 Transaction ID (is generated automatically)
00 00 Protocol ID
00 05 Length
01 Unit ID (device address of the CP9…)
04 Modbus function code 0x 04 (read input registers)
04 Length of the data (bytes)
01 00 43 63 Data floating point value (0x 43 63 01 00 (words swapped) = 227.0039)
00 04 Alarm and test type (00 = no alarm), range and unit (04 = volts)
5.2.4 Reference data records of the process image
To make it easier to check the configuration and the Modbus TCP data access to devices, the CP9… provides a
reference data record at the
virtual address 0.
Special features of the Modbus communication are the byte offset and the word and byte order in the memory
(Big Endian). At the end of this chapter, a few examples of correct configuration are given, which might be hel-
pful.
5.2.4.1 Address assignment of the reference data record
As shown in the following table, the Modbus start address for access to the reference data record is derived
from device address 0.
Tab. 5.3: Start addresses for the reference data record query
The start addresses provide the following reference values:

0x0000: TEST (device type)

0x000E: 1 (common alarm, LSB of the high byte is set)

0x0010: 230 V undervoltage (reference value on channel 1)

0x0014: 12.34 A overcurrent (reference value on channel 2)
Adress „0“
No real device can have address 0!
Address 0 only serves to simulate data access.
Word
Virtual
Device address
HiByte
LoByte
00 0E 10 14
0 HiByte 0x 00 Device type Common alarm Channel 1 Channel 2