gas_handling_system
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gas_handling_system [2018/04/11 16:12] pereira [Filling CRDC1 and CRDC2 with Gas] |
gas_handling_system [2020/03/01 14:50] pereira [Tracking Gas bottles pressures] |
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| ====== Detector gas handling system ====== | ====== Detector gas handling system ====== | ||
| - | * [[#General information]] | + | * [[#General information |
| - | * [[#LabView Control Program]] | + | * [[#LabView Control Program |
| - | * [[#Preparation of Gas bottles|Preparation of Gas bottles for filling of detectors]] | + | * [[# |
| * [[#Filling Ion Chamber with Gas]] | * [[#Filling Ion Chamber with Gas]] | ||
| * [[#Filling CRDC1 and CRDC2 with Gas]] | * [[#Filling CRDC1 and CRDC2 with Gas]] | ||
| * [[#Removing Gas from Focal Plane Detectors]] | * [[#Removing Gas from Focal Plane Detectors]] | ||
| + | * [[Venting/ | ||
| * [[#Tracking Gas bottles pressures|Tracking Gas bottles pressures from Barney]] | * [[#Tracking Gas bottles pressures|Tracking Gas bottles pressures from Barney]] | ||
| * [[# | * [[# | ||
| - | ===== General Information ===== | + | ===== General Information |
| + | The gas handling systems for both Focal Plane gas-filled detectors – the [[Detectors# | ||
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| + | The Labview software communicates with a MKS gas handling system through a Moax Nport 5110 terminal server attached to the bottom of the focal-plane chamber. This terminal server has a hostname s800ghts.nscl.msu.edu, | ||
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| + | Note that since the same roughing pump drives the gas handling systems for both gas-filled detectors, extra precautions must be taken to protect one detector from the pressure of the other detector. The fact that the same pump drives both systems is not indicated on the graphics for the LabView control application | ||
| Required controls and monitoring | Required controls and monitoring | ||
| * LabView gas handling system application **FPGHS_TCPIP-II.vi** | * LabView gas handling system application **FPGHS_TCPIP-II.vi** | ||
| * PanelMate **S800vac.ui page 07**: Focal Plane Detector | * PanelMate **S800vac.ui page 07**: Focal Plane Detector | ||
| - | The gas handling systems | + | ===== LabView Control Program |
| + | To start the gas handling system control application, | ||
| - | Note that since the same roughing pump drives | + | * The LabView program controls |
| + | * Go to Initialization tab | ||
| + | * Confirm | ||
| - | ===== LabView Control Program ===== | ||
| - | To start the gas handling system control application, | ||
| * A log file should be specified before operating the gas handling system | * A log file should be specified before operating the gas handling system | ||
| * A window automatically pops up asking for the name of the log file when the program starts | * A window automatically pops up asking for the name of the log file when the program starts | ||
| - | * Use the number of the current experiment (or " | + | * Use the number of the current experiment (or the date) as the name of the log file and save in the default directory **/projects/s800/Gas logs** |
| * The On indicator next to Is VI running? will flash until a log file is specified and the program initiates communications with the hardware | * The On indicator next to Is VI running? will flash until a log file is specified and the program initiates communications with the hardware | ||
| Line 37: | Line 49: | ||
| - | ===== Preparation of Gas bottles ===== | + | ===== Preparation of Gas bottles |
| ==== In Data-U6 ==== | ==== In Data-U6 ==== | ||
| Line 142: | Line 154: | ||
| * Open **valves 5 and 21** | * Open **valves 5 and 21** | ||
| - | * **IMPORTANT:** CLOSE **VALVE 25** to protect CRDCs from Ion Chamber pressure | + | * **IMPORTANT**: Before opening valve 8 (next step), |
| * Empty Ion Chamber to a pressure at or below the pressure of the CRDCs | * Empty Ion Chamber to a pressure at or below the pressure of the CRDCs | ||
| Line 157: | Line 169: | ||
| * Close **valves 8 and 24** | * Close **valves 8 and 24** | ||
| - | * Open **valves 6 and 22** | + | * Open **valves 6, 7, 22 and 23** |
| * Enter S3 vault and close valves downstream of regulators in [[# | * Enter S3 vault and close valves downstream of regulators in [[# | ||
| ===== Tracking Gas bottles pressures ===== | ===== Tracking Gas bottles pressures ===== | ||
| + | A rather conservative rule of thumb that helps estimate how much gas will be consumed during the course of an experiment assumes that when the detectors are filled and with gas running through them, the S800 IC detector consumes **~10 psi/day of P10**, and the CRDCs consume **~10 psi/day of CF4** and **~0.07 lb/day of Isobutane**. The process of filling the detectors, is approximately equivalent to 1 day of gas consumption during normal operations. | ||
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| In order to track the status of the gas bottles for the [[Detectors# | In order to track the status of the gas bottles for the [[Detectors# | ||
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| + | The gas content of each bottle is tracked by measuring the pressure in regulators (e.g. P10 and CF4) or the weight of the bottle on a scale. Both types of measured values are encoded in EPICS PVs, allowing remote monitoring of the gas available. There are two alarm levels (low alarm and high alarm) that can be adjusted using the corresponding EPICS PV. For instance, for the isobutane bottles (5 lb net weight), the low- and high-level alarms trigger at 1 lb and 0.5 lb, respectively. | ||
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| + | When installing a full bottle in a scale (e.g. isobutane), it is important to follow a procedure to account for the differences between the weight measured by the scale, and the actual gross weight. After removing an empty bottle, proceed as follows: | ||
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| + | Adjusting the pressured reading from a scale (for instance isobutane) requires some special guidelines. In the case of isobutane, the following EPICs PVs are involved: | ||
| + | * Check the weight marked in the scale when it is empty (no bottle). If different than zero, press "set zero" and ensure that it marks 0 lb | ||
| + | * Check the gross and net weight in the bottle (as seen in the labels) | ||
| + | * Install the bottle in the scale and check its weight. | ||
| + | * Update the following EPICS PVs with the correct values: | ||
| + | * I265DGWN: net weight, as marked in the bottle (e.g. 5 lb) | ||
| + | * I265DGWG: gross weight, as marked in the bottle (e.g. 41.6 lb) | ||
| + | * I265DGWS: weight, as read from the scale | ||
| + | * I265DGWC: correction factor used to match the scale weight and gross weight when the full bottle is installed. | ||
| + | * I265DGW: net weight deduced from the scale | ||
gas_handling_system.txt · Last modified: 2023/05/11 11:29 by pereira
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