#169 - Most Common Connections to Nova Analyzers (electrical & tubing)

In terms of customer interaction with Nova continuous analyzers, there are surprisingly few requirements. Especially on auto-cal equipped units, the instrument essentially calibrates and runs itself.

During installation and set-up, there are a few connections for the customer to be aware of. We can roughly categorize them as Power, Signal, and Gas.

Power

The vast majority of our continuous analyzers are AC powered using 115VAC / 60Hz or 220VAC / 50Hz. This is dictated by the country / region the instrument will be installed into. AC power is brought into the analyzer cabinet and terminated at the main terminal block located on the upper right hand side.

In some cases, a separate power supply may be brought into the cabinet if the customer has required an internal cabinet LEL monitor that can depower the analyzer during an alarm condition. The separate power supply allows the LEL monitor to continue functioning when the rest of the analyzer is depowered.

Signal

The analyzer will have a visual display of the gas readings. The most common format of communicating the gas readings to other parts of the customer’s instrumentation system is via 4-20mA output. The gas analysis range is co-related to a 4-20mA scale. There will be a separate output for each gas analyzed. The outputs are usually connected to the customer’s PLC or data collection system. The main terminal block will have the output connections clearly labeled as shown in the diagram.

Digital outputs such as RS-485, RS-232, and USB are also available on some Nova analyzers. The connection points will be on the main terminal block next to the 4-20mA outputs. We can also offer MODBUS protocol over Ethernet connection using a small convertor usually located under the main terminal block.

Gas

Obviously, there will be tubing connections on the analyzer to allow flow of sample gas or calibration gas.

The SAMPLE IN port is used during normal operation when the instrument is continuously measuring the gas. The tubing is connected to this port directly from the process or from another sampling component located between the process and analyzer. The SPAN and ZERO ports are used during calibration. The DRAIN port is located on the bottom of some analyzers and is used to evacuate condensate from the analyzer.

The tubing attached to the SAMPLE IN and DRAIN ports will usually contain various amounts of condensed water which can freeze if the analyzer is installed outside in cold weather. These tubing lines require heat-tracing to prevent freezing. (Note: the tubing shown in the picture is just temporary flexible tubing used during the manufacturing stages. The tubing used in on-site permanent installation will be stainless steel, PFTE, or another specified material.)

For information on these and other gas analyzer systems, give Mike or Dave at Nova a call, or send us an e-mail.

1-800-295-3771

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