Vaisala DPT146 - Manual (Page 68)

User's Guide _______________________________________________________________________
66 ___________________________________________________________________ M211372EN-D
APPENDIX A
MODBUS REFERENCE
This appendix describes the Modbus protocol implementation of the
DPT146 transmitters.
Default Communication Settings
Table 20 below shows the default communication settings when Modbus
is enabled at the factory.
Table 20 Default Communication Settings
Setting Default Value Configuration mode 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 6 on page 36.
NOTE You can also change device address with Modbus itself (register 1537).
Supported Modbus Functions
Table 21 Supported Function Codes
Function
Code
(decimal)
Function Code
(hexadecimal)
Function Name
(as defined by the specification)
Notes
3 03 Read Holding Registers See Table 22 on page 67
for available registers.
16 10 Write Multiple Registers See Table 22 on page 67
for writable registers.
43 14 2B 0E Read Device Identification See Table 23 on page 68
for available device
identification objects.
NOTE After power-up, wait for five seconds before sending Modbus requests.