User manual
90
DPMS XPQ User Manual
This chapter mainly discusses how to handle the meter via the
communication port using software. To master this chapter, you should be
familiar with Modbus and have read the other chapters in this manual. Once you
have completed these steps you will have mastered the function and application
of this product.
This chapter includes: Modbus protocol, the format of communication and
data address tables and application details.
Introducing Modbus Protocol
The Modbus RTU protocol is used for communication in the DPMS XPQ.
The data format and error check methods are dened in the Modbus protocol.
The half duplex query and respond mode is adopted in the Modbus protocol.
There is only one master device in the communication net. The others are slave
devices, waiting for the query of the master.
Transmission mode
The mode of transmission defines the data structure within a frame and
the rules used to transmit data. The mode is dened in the following which is
compatible with Modbus RTU Mode*.
Coding System 8-bit binary
Start bit 1
Data bits 8
Parity no parity
Stop bit 1
Error checking CRC check
* Modbus is trademark of Modicon, Inc.