Cameron LEFM 200 - Modbus Protocol Setups; Analog Inputs

LEFM 200 Modbus User Manual IB0147 Rev. 8
December 2010 Page 21 Section 3
3.4 Modbus Protocol Setups
Setup Variable
Holding Register
Variable
Definition
Address* Notes
Modbus Register
Update Period
Integer 168 Period (in seconds) that Modbus registers
are updated.
Note:
Value typically set to 5 seconds.
Values less than 4 may adversely
affect meter operation.
Modbus
Communications
Protocol
Integer 787 Communication Protocol Modbus RTU = 0
(Standard) Modbus ASCII = 1
Modbus Address Integer 788 Modbus address (default as delivered is
MODADDRESS = 1)
Modbus Baud Rate Unsigned
Integer
789 Allows different BAUD rates:
Choices
9600
19200
38400
It is noted, that if DIP Switch 2 is ENABLED on startup, the following occur:
Modbus address defaults to “1”
BAUD rate defaults to “9600”
This default state is discontinued if the software is re-started with the DIP Switch 2 set to
Disabled (down). Further, if DIP Switch 2 is ENABLED on startup, the software will wait for a
setup before it starts to collect data.
3.5 Analog Inputs
Each analog input is scaled using four parameters as follows:
Input Scaling - X1, Y1, X2, Y2
X1 and X2 are in volts (Min = 0; this is associated with 0 volts. Max = 5). Note: The 4 – 20 mA
input is converted to 0 to 5 volts (as is the RTD input).
Y1 and Y2 are in engineering units. Where:
X1 = Minimum limit voltage
Y1 = Engineering value associated with the minimum voltage
X2 = Maximum limit voltage
Y2 = Engineering value associated with the Maximum voltage