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Micromod MOD: MODBUS RTU Communications Guide User Manual

Page 20

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MODBUS RTU

COMUNICATIONS GUIDE

16

MODBUS WITH FIX AND COMMANDER 300

Either the MB1 or EMP driver may be used, though EMP is recommended. The MODBUS guide uses 3-digit
numbers for addresses. Note that the actual addressing requires a 5-digit number. For digital addresses, use
00xxx format, where xxx represents the coil address from the instruction book. For analog addresses, use
40xxx format, where xxx represents the register address from the instruction book.

Table 7. MODBUS with FIX and Commander 300

Poll Record Configuration
Hardware

MODBUS

Addressing Type

5-Digit

Bit Base

0-15

Data Type

Unsigned - Positive Analog Ranges (0 to 4095)
Signed - Analog Ranges that go Negative (-2048 to +2047)

Database Configuration

Data Type

Database Block

Address Range

Notes

Digital Input

DI

00xxx

Digital Output

DO

00xxx

Digital I/O

DR

00xxx

select output enable

Analog Input

AI

40xxx

12BN (positive) or LZ12 (live zero)
Signal Conditioning

Analog Output

AO

40xxx

12BN (positive) or LZ12 (live zero)
Signal Conditioning

Analog I/O

AR

40xxx

12BN (positive) or LZ12 (live zero)
Signal Conditioning

NOTES:
1. Ensure that each line of the poll record contains no more than 8 analogs or 16 digital addresses.
2. It is acceptable to “read through” undefined addresses.