janitza UMG 512-Pro, User Manual And Technical Data

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UMG 512-PRO www.janitza.com
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12.11 Communication in the bus system
12.11.1 RS-485
The data from the parameter and measurement
list can be accessed via the MODBUS RTU proto-
col with CRC check at the RS-485 interface (see
„11.2.2 Fieldbus“).
Modbus functions (master)
01 Read Coil Status
02 Read Input Status
03 Read Holding Registers
04 Read Input Registers
05 Force Single Coil
06 Preset Single Register
15 (0F Hex) Force Multiple Coils
16 (10Hex) Preset Multiple Registers
23 (17Hex) Read/Write 4X Registers
Modbus functions (slave)
03 Read Holding Registers
04 Read Input Registers
06 Preset Single Register
16 (10Hex) Preset Multiple Registers
23 (17Hex) Read/Write 4X Registers
The order of the bytes is high before low byte
(Motorola format).
Transmission parameters
Data bits: 8
Parity: none
Stop bits (UMG 512-PRO): 2
External stop bits: 1 or 2
Number formats
short 16 bit (-2
15
.. 2
15
-1)
float 32 bit (IEEE 754)
INFORMATION
Broadcast (address 0) is not supported by the
device.
INFORMATION
The telegram length must not exceed
256 bytes.
Example: Reading the voltage L1-N
The voltage L1-N is stored in the measurement list
under the address 19000. The voltage L1-N is in
the FLOAT format.
In this example 01 is assumed as the device
address.
The "Query Message" then looks as follows:
Designation Hex Comment
Device address 01 Address=1
Function 03 “Read Holding Reg”
Start address Hi 4A 19000dec = 4A38hex
Start address
Lo
38
No. of values Hi 00 2dec = 0002hex
No. of values Lo 02
Error check
(CRC)
-
The "Response" of the device can then look as
follows:
Designation Hex Comment
Device address 01 Address=1
Function 03
Byte counter 06
Data 00 00hex=00dec
Data E6 E6hex=230dec
Error check
(CRC)
-
The voltage L1-N read out from address 19000 is
230 V.