Issue/Rev. 0.1 (9/13) ║ MNFL003 • Page 3
Table of Contents
1 – Introduction ........................................................................................................................................................................... 5
1.1 – Modbus/TCP ........................................................................................................................................................................ 5
1.2 – Floating Point Endian Control .............................................................................................................................................. 6
1.3 – Communications Control Selections.................................................................................................................................... 6
1.4 – Configuring the microFlow.net Liquid for Modbus Communications via Serial Port ............................................................ 6
1.5 – Configuring the microFlow.net Liquid for Modbus Communications via TCP/IP (Ethernet or SLIP) ................................... 7
2 – Implementing Remote Host Functionality .......................................................................................................................... 8
2.1 – Implementing Host Status Polling........................................................................................................................................ 8
2.2 – Implementing Host Control (Automation) Interface via Modbus .......................................................................................... 8
2.21 – Special Modbus Registers for Host Control....................................................................................................................... 8
2.22 – Host Command Result Status Register ............................................................................................................................. 8
2.23 – Program Mode Interface-Entering Program Mode via Modbus ......................................................................................... 9
2.24 – Program Mode Interface-Explicit Logout Command.......................................................................................................... 9
2.25 – Set Time/Date .................................................................................................................................................................. 10
2.26 – Alarm Clearing ................................................................................................................................................................. 10
2.27 – Other Host Clearable Flags (Program Change, Power Fail, Transaction/Batch Done, etc.) ........................................... 10
2.28 – Set Max Transaction Amount........................................................................................................................................... 10
2.29 – Allocate Recipes .............................................................................................................................................................. 10
2.30 – Batch Preset/Authorization Options..................................................................................................................................11
2.31 – Read Transaction Log ......................................................................................................................................................11
2.32 – Read Event Log ............................................................................................................................................................... 12
2.33 – Read Audit Log ................................................................................................................................................................ 12
3 – Modbus Register Reference .............................................................................................................................................. 13
4 – Appendix ............................................................................................................................................................................. 22
4.1 – Modbus Communications Primer ...................................................................................................................................... 22
4.11 – RTU Framing ................................................................................................................................................................... 22
4.12 – How Characters are Transmitted Serially ........................................................................................................................ 23
4.13 – Data Addresses in Modbus Messages ............................................................................................................................ 23
4.2 – Modbus Functions ............................................................................................................................................................. 23
4.3 – Master/Slave Communications .......................................................................................................................................... 24
4.4 – Contenes of the Data Field ................................................................................................................................................ 24
4.41 – Beginning Register .......................................................................................................................................................... 25
4.42 – Number of Requested Registers ..................................................................................................................................... 25
4.43 – Error Check (CRC16) ...................................................................................................................................................... 25
4.5 – Placing the CRC into the Message.................................................................................................................................... 25
4.51 – Field Contents in Modbus Messages .............................................................................................................................. 26
4.52 – Address............................................................................................................................................................................ 27
microFlow.net Liquid Modbus Communications Manual
Table of Contents
