Automationdirect.com HX-ECOM Series - Example 1: Calculating Word PLC Address; Example 2: Calculating Discrete Input PLC Address

Ethernet Communications Modules, 3rd Edition, Rev. D
5-18
Chapter 5: MODBUS TCP for H0/H2/H4-ECOM100
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NOTE: Your PC’s Windows calculator can be used for number conversions (i.e. decimal to octal). The
Windows calculator must be in Calculator>View>Scientific mode to enable number conversions capability.
Example 1: Calculating Word PLC Address
Find the PLC address to use to target Modbus
address 41025 in a server device.
1. Subtract the beginning of the Modbus word
address range (40001) from the desired
Modbus address to target.
2. Convert decimal result into octal.
3. Add octal result to beginning PLC range
(Input, Output or Word).
Find the PLC address to use to target Modbus
address 12060 in a server device.
1. Subtract the beginning of the Modbus Input
address range (12049) from the desired
Modbus address to target.
2. Convert decimal result into octal.
3. Add octal result to beginning PLC range
(Input, Output or Word).
1. 41025 - 40001 = 1024 decimal
1. 12060 - 12049 = 11 decimal
2. 1024 decimal = 2000 octal
2. 11 decimal = 13 octal
3. V0 (octal) + 2000 (octal) = V2000 octal
3. X0 (octal) + 13 octal = X13 octal
Example 2: Calculating Discrete Input PLC Address