CONTENTS
2 www.honeywell.com/ps 34-VF-25-22 iss.1 GLO Nov 09 US
TWM 9000
1 Important information 3
2 Technical data 5
2.1 General technical data .....................................................................................................5
2.2 Technical data of the Modbus interface (acc. to EIA standards) ..................................... 5
3 Connection in bus systems 7
4 Local configuration 9
5 Electrical connection 11
6 Modbus protocol 13
6.1 General information concerning the protocol ............................................................... 13
6.2 RTU frame format...........................................................................................................13
6.3 Addressing...................................................................................................................... 14
6.4 Overview of supported functions.................................................................................... 14
6.5 Device identification on the Modbus interface............................................................... 15
6.6 Coil registers .................................................................................................................. 15
6.6.1 Converter controls ................................................................................................................ 15
6.6.2 Counter controls ................................................................................................................... 16
6.6.3 Start calibration functions .................................................................................................... 16
6.7 Input registers ................................................................................................................ 17
6.8 Holding registers............................................................................................................ 18
6.8.1 Counter parameters ............................................................................................................. 18
6.8.2 Process input filter parameters ........................................................................................... 19
6.8.3 Modbus parameters.............................................................................................................. 21
6.9 Diagnostics ..................................................................................................................... 21
6.10 Calibration procedures................................................................................................. 22
6.10.1 Zero Flow Calibration.......................................................................................................... 22
6.10.2 Coil Temperature Calibration ............................................................................................. 23
6.10.3 Conductivity Calibration...................................................................................................... 24
