User`s guide

User's Guide _______________________________________________________________________
60 ___________________________________________________________________ M211371EN-D
APPENDIX A
MODBUS REFERENCE
This appendix describes the Modbus protocol implementation of the
DPT145 transmitters.
Default Communication Settings
Table 19 below shows the default communication settings when Modbus
is enabled at the factory.
Table 19 Default Communication Settings
Setting
Default Value
Configuration Command
for Changing the Value)*
Bit rate
19200
SERI
Number of data bits
8
Parity
E
Number of stop bits
1
Device address
240
ADDR
Response delay
0
SDELAY
Communication mode
MODBUS
SMODE
* See Table 5 on page 33.
NOTE
You can also change device address with Modbus itself (register 1537).
Supported Modbus Functions
Table 20 Supported Function Codes
Function
Code
(decimal)
Function Code
(hexadecimal)
Function Name
(as defined by the
specification)
Notes
3
03
Read Holding Registers
See Table 21 on page 61 for
available registers.
16
10
Write Multiple Registers
See Table 21 on page 61 for writable
registers.
43 14
2B 0E
Read Device Identification
See Table 22 on page 62 for
available device identification objects.
NOTE
After power-up, wait for five seconds before sending Modbus requests.