MODBUS Protocol and MODBUS Register Tables

The iQ Series of gas analyzers use MODBUS protocol which enables the user to perform the functions of reading the various concentrations and other measurement values, read the status of the digital outputs of the analyzer, to trigger or simulate the activation of a digital input to the instrument and to change operational settings in the instrument.

The MODBUS commands that are implemented are explained in detail in the iQ Communications Manual. iQ Series Communications Manual.

MODBUS register tables are easily found on thermofisher.com. To locate the most current list of MODBUS registers, go to the appropriate iQ instrument product page (see below) and scroll to the bottom of the page to the Documents section.

• 42iQ (NO-NO2-NOx) Analyzer
• 42iQ Low Source NO-NO2-NOx Analyzer
• 43iQ Sulfur Dioxide Analyzer
• 48iQ Carbon Monoxide Analyzer
• 410iQ Carbon Dioxide Gas Analyzer
• 410iQ High Level Carbon Dioxide Gas Analyzer
• 49iQ Ozone Primary Standard
• 49iQPS Ozone Primary Standard
• 146iQ Multi-Gas Calibrator

• 42iQ & 42iQLS Modbus register table
• 43iQ Modbus register table
• 48i, 410iQ & 410iHL Modbus register table
• 49iQ & 49iQPS Modbus register table
• 146iQ Modbus register table

iSeries Discontinuation
Just a reminder, with the offering of the iQ series analyzers, we will no longer accept orders for 42i, 42iLS, 43i, 48i, 49i, 49iPS, 410i, 146i and 111i gas analyzers after June 30, 2018. Consumables, spare part and service (based on availability) will be accepted until December 31, 2025.