User guide
Multi Process Meter   Instruction Manual 
72
Modbus RTU Serial Communications (serial) 
The meter is equipped with serial communications capability as a 
standard feature using Modbus RTU Serial Communication Protocol. 
To communicate with a computer or other data terminal equipment, an 
RS-232 or RS-485 option is required; see Ordering Information on 
page 7 for details. 
Note: More detailed instructions are provided with each optional serial 
communications adapter. 
Note: Refer to the Modbus Register Tables located at www.dwyer-
inst.com for details. 
When using more than one meter in a multi-drop mode, each meter 
must be provided with its own unique address. The meter address 
(Slave ID) may be programmed between 1 and 247. The transmit delay 
may be set between 0 and 199 ms. The parity can be set to even, odd, 
or none with 1 or 2 stop bits. 
The MPM can also be connected to another MPM with a special PMA-
02 cable, allowing the user to copy all the settings from one meter to 
another, using the Copy function. 
Warning! 
Do not connect any equipment other than Dwyer 
Instruments, Inc.’s expansion modules, cables, or 
meters to the RJ45 M-LINK connector. Otherwise 
damage will occur to the equipment and the meter. 










