Laurel Electronics Modbus Protocol For Series 2 Laureate Digital Panel Meters, Counters, Timers & DIN-Rail Transmitters - Manual (Page 11)

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4. PARAMETERS SELECTABLE VIA INSTRUMENT SETUP (IS) SOFTWARE
Serial Protocol ..................................................Custom ASCII, Modbus RTU, Modbus ASCII
Modbus ASCII Gap Timeout.......................................................... 1 sec, 3 sec, 5 sec, 10 sec
Baud Rate..............................................................300, 600, 1200, 2400, 4800, 9600, 19200
Parity ...............................No parity, 2 stop bits; odd parity,1 stop bit; even parity, 1 stop bit
Device Address .........................................................................................................0 to 247
5. PARAMETERS SELECTABLE VIA FRONT PANEL METER SETUP
The two menu items related specifically to Modbus setup are SEr_4 and Addr.
000
Modbus ASCII Gap Timeout 0 1 Sec 2 5 Sec
1 3 Sec 3 10 Sec
000
Serial Protocol 0 Customl ASCII (Non-Modbus)
1 Modbus RTU
2 Modbus ASCII
SEr_4
Serial Comm 4
000
Parity 0 No Parity, 2 or more stop bits
1 Odd Parity, 1 or more stop bits
2 Even Parity, 1 or more stop bits
Addr 000 Meter Address Set to desired address 1-247
The baud rate is set in SEr_1 per the Meter manual. The selection of Modbus RTU or
Modbus ASCII in SEr_4 above overrides any LF or Command Mode selections that have
been made, since they are determined by the Modbus protocol.
6. SUPPORTED FUNCTION CODES
FC03: Read Holding Registers. Reads internal registers containing setup parameters
(Scale, Offset, Setpoints, etc.)
FC04: Read Input Registers. Reads measurement values and alarm status
FC05: Write Single Coil. Action command to device
FC08: Diagnostics. Checks communications between Master and Slave.
FC10: Write Multiple Registers (FC10 = 16 dec). Writes internal registers containing
setup parameters (Scale, Offset, Setpoints, etc.)
7. REGISTER NUMBERS VS. METER ADDRESSES
Some Master devices (e.g., Modicon) require that the desired Register Number and not the
Register Address be entered. The Register Number is 1 higher than the Register Address.
For entry to these devices, add 1 to the Register Address shown in the tables below. The
Register Address shown will then be output from these devices.