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oxygen_monitors [2021/06/10 17:59]
leblanc
oxygen_monitors [2021/06/23 12:49] (current)
leblanc
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 A plot of the oxygen readings from the dock can be found at [[https://​inpp.ohio.edu/​~oual/​tandem/​oual_Dock_O2.jpg]] A plot of the oxygen readings from the dock can be found at [[https://​inpp.ohio.edu/​~oual/​tandem/​oual_Dock_O2.jpg]]
  
-==== LN2 ==== +==== Lab 115 - LN2 ==== 
-Got some of this in room 115.+The lab/office space in room 115 is where dewars of Liquid Nitrogen (LN2) are stored. ​ Although air is composed of 78% nitrogen, LN2 is roughly 650 times more dense than air.  A spill of LN2 can easily displace enough oxygen from a room to create an asphyxiation hazard. ​  
 +The O2 monitor in this room is located on the wall to the right of the door from the lab hallway, approximately 1m (3 ft) from the door 
  
 ==== Monitoring Equipment ==== ==== Monitoring Equipment ====
-Oxygen deficiency is monitored in the lab using 2 [[https://​www.amio2.com/​oxygen-analyzers/​oxygen-deficiency-monitors/​model-221r/​|AMI Model 221R Oxygen Deficiency Monitors]]. ​ These monitors were installed in June 2021 by Don Carter and Greg Leblanc. ​ + 
 +>**Below this point is the nitty-gritty details on the oxygen monitors, wiring, manuals, etc.  Operators shouldn'​t need to refer to this information,​ but it is made available for all.** 
 + 
 +=== Equipment Info === 
 + 
 +Oxygen deficiency is monitored in the lab using 2 [[https://​www.amio2.com/​oxygen-analyzers/​oxygen-deficiency-monitors/​model-221r/​|AMI Model 221R Oxygen Deficiency Monitors]]. ​ These monitors were installed in June 2021 by Don Carter and Greg Leblanc. 
 Normal oxygen content is **20.9%**. ​ The current oxygen reading will be be displayed on the red LED numbers on the monitor. ​ The monitor should also show a green power LED under normal conditions.  ​ Normal oxygen content is **20.9%**. ​ The current oxygen reading will be be displayed on the red LED numbers on the monitor. ​ The monitor should also show a green power LED under normal conditions.  ​
 +
 If low oxygen is detected, an alarm will sound, and the area should be evacuated, and accelerator staff contacted. If low oxygen is detected, an alarm will sound, and the area should be evacuated, and accelerator staff contacted.
  
 +Correspondence with AMI can be found at: {{::​ami_sensor_replacement.pdf|}} and also at {{::​ami_2021-06-22.pdf|}}.
 +
 +  * Sensor data sheet: ​
 +    * Web link: [[https://​www.amio2.com/​img/​model-221r/​model-221r-data-sheet.pdf]]
 +    * Local copy (retrieved 2021-06-22):​ {{::​model-221r-data-sheet.pdf|}}
 +  * Sensor (w/remote probe) data sheet: ​
 +    * Web link: [[https://​www.amio2.com/​img/​model-221r-w-remote/​model-221r-w-remote-data-sheet.pdf]]
 +    * Local copy (retrieved 2021-06-22):​ {{::​model-221r-w-remote-data-sheet.pdf|}}
 +  * Operator manual: ​
 +    * Web link: [[https://​www.amio2.com/​img/​model-221r/​model-221r-operator-manual.pdf]]
 +    * Local copy (retrieved 2021-06-22):​ {{::​model-221r-operator-manual.pdf|}}
 +
 +== Sensor Info ==
 +The monitors are equipped with remote probes, to allow placement closer to the floor, since the risk is primarily from heavier than air gasses. ​ The Ziurconium Oxide sensors used in these devices are expected to have a 10 year service life.  The sensor is located in the remote probe, and could theoretically be sent back for repair separately from the head unit.  AMI recommends returning both the head unit and sensor together. ​ Sensors are approaching end of life when their span factor is approaching 1000.  The span factor can be checked through the command center software, or by pressing the "​up"​ button on the front panel.
 +
 += Calibration Info =
 +The sensors should be calibrated quarterly. ​ We should add this to our quarterly radiation safety checks.
 +
 +=== Communication Info ===
 +The oxygen monitors come equipped with 3 modes of external communication:​ RS-485 (single-point),​ 4-20 mA analog output, and 2 relay outputs.
 +
 +== RS-485 ==
 +Communication with the RS-485 port on these devices is accomplished by using an FTDI USB-to-RS-485 adapter. ​ This adapter only allows communication with a single device. ​ Control of the devices is accomplished using the [[https://​www.amio2.com/​command-center/​|AMI command center software]], running on Windows. ​ This software is currently installed on a computer in the control room, but will eventually be migrated to the VESDA monitoring computer. ​ Currently a single twisted pair line is connected from the control room to the unit in the vault, and then daisy-chained to the unit on the dock.  However, since the software is only capable of communicating with a single unit, the connector must be unplugged from one unit or the other in order to successfully communicate.
 +
 +== 4-20 mA analog output ==
 +These devices utilize a standard 4-20 mA analog signal for integration with control systems. ​ A 510Ω 1% metal film resistor is installed in across the terminals, converting this to a 2-10V signal. ​ 2 twisted-pairs are used from the control room to the pit, and then an one twisted-pair is used out to the dock.
 +
 +== Relay Outputs ==
 +These units are equipped with 2 alarm output relays, each with NO and NC contacts. ​ Currently these outputs are not connected anywhere. ​ We may eventually want to connect them to a "​remote"​ set of alarms located in the control room.  ​
  
 +=== Data logging ===
 +Data logging for these devices is accomplished by landing the 2-10V signal wires into the HP/​Agilent/​Keysight 34980A unit located in the control room.  FIXME: I would list the input numbers here, but I can't remember what they are (hopefully Don has some notes).
  
oxygen_monitors.1623362399.txt.gz · Last modified: 2021/06/10 17:59 by leblanc