4220 Flow Meter Section 3 Installation
3.5 Extension Cables
mersion when the stream is high, you should protect the desic- cator and the reference port by venting them at a point the water cannot possibly reach.
Remember that water or other blockage inside the submerged probe's vent tube will ruin the submerged probe. It is even more important to protect the
The standard (10 foot depth) probe for the 4220 has a
CAUTION
The submerged probe extension cables and the submerged probe cable cannot be cut for any reason, or they will be ruined. The connectors are
CAUTION
Teledyne Isco does not recommend connecting multiple exten- sion cables together in an attempt to exceed the 75 foot limit. Increasing the length of the vent tube beyond 75 feet slows the response of the pressure transducer, and this may cause mea- surement errors. For greater distances, use the
The submerged probe uses a differential pressure transducer. The cable connecting the submerged probe to the flow meter con- tains a small tube that references the pressure transducer to atmospheric pressure. This allows a true differential pressure measurement unaffected by changes in barometric pressure. This tube is vented through the connector into the cabinet of the 4220 Flow Meter. From there, it is vented to the atmosphere through a desiccant cartridge mounted on the side of either the flow meter or the
3.6Safety Considerations In field installations of 4220 Flow Meters and associated equipment, the safety of the personnel involved should be the foremost consideration. No project is so important or deadline so critical as to justify the risk of human life.
We urge you to read the safety procedures provided in Appendix
D.
