Processing Magazine

New programmable control module for digital mass flowmeters

May 26, 2009

New programmable control module, the Compod™, coupled with Sierra’s Smart-Trak® mass flow meters (MFM’s) and controllers (MFC’s), greatly simplifies basic flow control installations and permits networking of multiple instruments using open-source MODBUS RTU protocol. By adding the Compod™ module to a new or existing Smart-Trak® MFM or MFC, end users can take complete control. Two digital outputs and one analog input can be configured by the end user for a wide variety of process controls including gas mixing and blending, gas ratio control, simple batch processes, triggering alarms, starting or stopping gas flows automatically under user-defined conditions and gas flow totalization. Compod™ also monitors the functionality of the mass flow meter or controller and includes diagnostics, notifying users of faults or system updates. The Compod™ mounts to any Sierra Smart-Trak® 100 Series converting the instruments’ internal RS-232 communications into multi-drop RS-485/MODBUS RTU. With MODBUS, multiple instruments can be daisy-chained over a single network. When used with a PLC or master computer, each instrument equipped with Compod™ becomes a node on the MODBUS network, capable of sending and receiving data, and commands. Even complex process control systems can be automated with the power of Compod™ and Sierra’s Smart-Trak® 100 Series.