Emerson MON2020 Gas Grill User Manual


 
Comparing SIM_2251 and User_Modbus ProtocolsTable 7-1:
SIM_2251 User_Modbus
A modified protocol that allows a floating point
number to be assigned to a single register so
that it can be transmitted over Modbus via 2251
emulation slave type.
Standard Gould protocol that accommodates
PLC Emulation LO-HI or HI-LO word order for 32-
bit values.
The GC uses the LO-HI order.
Most register contents are predefined.
The pre-configured maps conform to the SIM_
2251 register designations that are the de facto
standard for GC communications in custody
transfer applications.
Predefined Boolean (coils)
User-defined Numeric (registers)
Data types are predefined for the following reg-
ister ranges:
1001-2999 discrete, coils
3001-4999 16-bit integers
5001-6999 32-bit integers
7001-8999 IEEE 32-bit floats
Data types are user-defined
When using the Modbus test program, set Regis-
ter Mode to “DANIEL” to view register contents.
When using the Modbus test program, set Regis-
ter Mode to “PLC- LH” or “PLC-HL” to view regis-
ter contents.
It is not necessary to assign scales to registers. It may be necessary to assign scales to registers,
to convert floating point values to whole integer
representations.
7.1.2 Set communication parameters
To determine or reset the communications parameters used by the Modbus program, do
the following:
1. Select Modbus Test... from the Tools menu.
The Modbus Test Program window displays. The current port settings display in the
window’s title bar.
2. Click Port Setup.
The Port Setup window appears.
3. Make the appropriate configuration changes to match the settings for the link you
are trying to test. The following table lists the typical setting for each parameter:
Parameter RTU ASCII
Port COM1 or COM2 COM1 or COM2
Baud Rate 9600 9600
Tools
156