Sierra Series 830/840/860 Side-Trak™ and ... - Sierra Instruments

Chapter 3 OperationSeries 830/840/860 Instruction ManualCaution!Do not use the manualpurge functionwhen RS-485 is active.Valve Purge FunctionElectromagnetic valves are driven with either 15 or 30 volts dependingon the range and pressure. In general, units below 10 slpmhave the 15 volt valve. When the purge function occurs, electromagneticvalves are driven fully open regardless of the set pointinput. Furthermore, the purge function will override any valve-offfunction. This option is not available on motor-operated rotaryvalves. Motor-operated valves are purged by setting the commandsignal to full scale. There is no equivalent monitor function.The Model 860 allows valve monitoring and the purge function tobe utilized in either analog or digital (RS-485) mode. If both hardwareand software control options are used simultaneously on an860, conflicts may occur that can produce undesired results.For +15 Volt Valve Controllers: The valve purge function is activatedwhen the Valve Test Point/Purge connection is connected toground. The maximum valve voltage is indicated in the “comments”field of the calibration certificate. (Units with ranges below 10slpm)For +30 Volt Valve Controllers: The valve purge function is activatedwhen the Valve Test Point/Purge connection is connected to+15 VDC. The maximum valve voltage is indicated in the “comments”field of the calibration certificate.A Sierra controller intended as a replacement for another manufacturer’scontroller may have Pin D and other pins disconnected. Someoptions may not be available.Purging Non-Reactive Gases:Purge the transducer with clean, dry nitrogen for a minimum of two hours.Caution!Always fully neutralize anytoxic gas trapped inside thetransducer before removingfrom the gas line.Purging Reactive Gases:One of the following methods may be used:• Cycle purge. This is done by alternately evacuating and purgingthe transducer for two to four hours with clean, dry nitrogen.• Purge the transducer with clean, dry nitrogen for eight totwenty-four hours.• Evacuate the transducer for eight to twenty-four hours.When toxic or corrosive gases are used, purge unit thoroughly withinert dry gas before disconnecting from the gas line. If a transducerused with a toxic or corrosive gas is returned to the factory, a Ma-3-6 IM-83/84/86-H