Teledyne NALL instruction manual Filters, Cables, Power Supply

The use of O-ring seal connectors on the transducers with female threads is often more convenient for many low pressure applications, such as with U-Series transducers.

4.1.5Checking for Leaks

Check the transducer connections for leaks by pressurizing the line to the operating pressure (not to exceed 250 psig except on high pressure models), and applying a diluted soap solution to the pipe joints. Any gas escaping from the pipe joints will cause a continuous stream of bubbles.

4.2FILTERS:

If the flow stream carries particles large enough to block the small passages inside the transducer (approximately .02” ID) a filter should be installed in the flow line of the inlet side of the transducer.

4.3CABLES

4.3.1Description

A standard 5-conductor 20 gauge shielded 8-foot long cable (NF-8-NM) is normally ordered with each flowmeter and is used for connecting the power and the transducer. Longer cables are available upon special request.

4.3.2Cable Length

The cable length can be extended to 25 feet without changing the calibration of the flowmeter by more than SP+/-1% of the rated full scale flow. Cables longer than 25 feet will cause the indicated flow rate to be lower than the actual flow rate and recalibration may be required. (See Section 7.0 for calibration procedures.)

4.3.3Cable Conductor Size

In the event cable conductors larger than #20 are desired, the connecting cable can be extended to greater lengths without having to recalibrate the flowmeter. The table below shows the relationship of the conductor size to the maximum cable length that can be used without changing the calibration by more than 1% of full scale.

4.4POWER SUPPLY:

4.4.1Mounting

One type of housing available for the power supply is a small metal cabinet, 7.75” X 5.75”X 5.75”, which can sit on a table or desk or can be mounted securely on a bracket. The “NIM” style package is 5.41” X 8.71” X 9.68”, and can be housed in an 8.75” X 19.00” relay rack-panel.

4.4.2Electrical Connections

Connect the power supply to the transducer with the NF-8-NM connecting cable (Section 4.3) and connect the AC line cord to a suitable power source (Section 3.4).

Manual 111-082010_Nall Mass Flowmeters Page 9 of 23