Sel 2414 - Read Holding Register Command; Read Input Register Command

E.3
Date Code 20130214 Instruction Manual SEL-2414 Transformer Monitor
Modbus Communications
Function Code Details
In each row, the input numbers are assigned from the right-most input to the left-
most input (i.e., Input 1 is N and Input 8 is EN). Input addresses start at 0000
(i.e., Input 1 is located at Input Address 0000). Table E.4 includes the coil
address in decimal and hex and lists all possible inputs (Device Word bits) avail-
able in the device. Note that the command depends on the device hardware con-
figuration; the device responds only to installed cards. The device responses to
errors in the query are shown in Table E.5.
03h Read Holding
Register Command
Use function code 03h to read directly from the Modbus Register Map shown in
Table E.15.
You can read a maximum of 125 registers at once with this function code. Most
masters use 4X references with this function code. For five-digit addressing, add
40001 to the standard database address.
The device responses to errors in the query are shown in Table E.6.
04h Read Input
Register Command
Use function code 04h to read directly from the Modbus Register Map shown in
Table E.15. You can read a maximum of 125 registers at once with this function
code. Most masters use 4X references with this function code. For five-digit
addressing, add 40001 to the standard database address.
Table E.4 02h Input Status/Register
Coil Address
in Decimal
Coil Address
in Hex
Function Code
Supported
Coil Description Notes
0–7 0–7 02h Device Element Status Row 0 The input numbers are assigned from the
right-most input to the left-most input in the
device row as shown in an example below.
Address 7 = Enabled
Address 6 = T00_LED
Address 5 = T01_LED Address 4 =
T02_LED Address 3 = T03_LED Address 2
= T04_LED Address 1 = T05_LED Address
0 = T06_LED
8–15 8–F 02h Device Element Status Row 1
16–1055 10–41F 02h Device Element Status Row 2–131
Table E.5 Responses to 02h Read Input Query Errors
Error Error Code Returned
Communication Counter
Increments
Invalid bit to read Illegal Data Address (02h) Invalid Address
Invalid number of bits to read Illegal Data Value (03h) Illegal Register
Format Error Illegal Data Value (03h) Bad Packet Format
Table E.6 Responses to 03h Read Holding Registry Query Errors
Error Error Code Returned
Communication Counter
Increments
Invalid register to read Illegal Data Address (02h) Invalid Address
Invalid number of registers to read Illegal Data Value (03h) Illegal Register
Format Error Illegal Data Value (03h) Bad Packet Format