Vaisala DPT145 - Manual (Page 60)

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.