Go to the U of M home page
School of Physics & Astronomy
Assay and Acquisition of Radiopure Materials

User Tools

Trace:
vetoshield:gas

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
vetoshield:gas [2015/04/27 11:54] – jeffvetoshield:gas [2015/07/29 13:15] (current) – [References and Additional Information] jeff
Line 45: Line 45:
 __Solenoid Valves__- These are the six toggle switches located to the right of the pump controls. In auto mode, they are monitors that display the states of the respective valves ((There is no feedback from the solenoid valves. So the valve states as indicated here are merely the control signals the computer is sending to the valves. If everything is working properly the actual valve state should mirror the control signal and this detail can be ignored.)). Up indicates open and down indicates closed. In override, these six switches become controls allowing the user to manually open and close the valves. __Solenoid Valves__- These are the six toggle switches located to the right of the pump controls. In auto mode, they are monitors that display the states of the respective valves ((There is no feedback from the solenoid valves. So the valve states as indicated here are merely the control signals the computer is sending to the valves. If everything is working properly the actual valve state should mirror the control signal and this detail can be ignored.)). Up indicates open and down indicates closed. In override, these six switches become controls allowing the user to manually open and close the valves.
    
-__Filter Display__- When this button is pressed, the front panel monitors will be low pass filtered (smoothed). The RC time constant can be changed by clicking the "Limits and Setpoints" button and then going to the Advanced tab.+__Filter Display__- When this button is pressed, the front panel monitors will be low pass filtered (smoothed). The equivalent RC time constant can be changed by clicking the "Limits and Setpoints" button and then going to the Advanced tab. The gage pressure used to compute the tube absolute pressure is filtered for at least 10 seconds before being displayed or otherwise used by the program regardless of this button's state.
  
 __Override Switches__- These switches are intended to be used in auto mode when a specific safety prevents the pump from running continuously. See the section below for more information regarding the safeties. __Override Switches__- These switches are intended to be used in auto mode when a specific safety prevents the pump from running continuously. See the section below for more information regarding the safeties.
Line 101: Line 101:
 The limits can be changed while the controller is running by clicking on “Limits and Setpoints” on the front panel. A new window will appear and all pump stop criteria is adjustable from the "Pump Stop Criteria" tab. When finished click either “Cancel” or “Accept Values” to close the window. Do NOT close the window by clicking the red “x” in the upper right corner. Doing so will require a restart of the controller program for everything to again work properly.  The limits can be changed while the controller is running by clicking on “Limits and Setpoints” on the front panel. A new window will appear and all pump stop criteria is adjustable from the "Pump Stop Criteria" tab. When finished click either “Cancel” or “Accept Values” to close the window. Do NOT close the window by clicking the red “x” in the upper right corner. Doing so will require a restart of the controller program for everything to again work properly. 
  
-In certain situations, one or more safeties may need to be temporarily bypassed. Such is common if the pump has been left off for an extended period of time and an appreciable amount of O2 has seeped into the system. In this case the KR and O2 readings may be outside their limits. A safety can always be bypassed by setting the corresponding limit arbitrarily large or small. For example, if the KR is malfunctioning and reading very low, the KR Lower Limit can be set to 0 or some negative value that it will never reach. Alternatively, there are three override switches, one for the O2 levels, one for the pressure levels and another for the KR. Turing any one or more of these switches to ON will cause the controller to ignore the respective safeties. For example, the same problem with the KR could be addressed by instead turning the KR override to ON without tampering with the lower limit. The “Pressure Override” simultaneously bypasses all four pressure limits and the “O2 Override” simultaneously bypasses both O2 limits.+In certain situations, one or more safeties may need to be temporarily bypassed. Such is common if the pump has been left off for an extended period of time and an appreciable amount of O2 has seeped into the system near the KR and/or the O2 sensors. In this case the KR and O2 readings may be outside their limits. If the pump has not been running, these readings are not representative of the average gas quality throughout the shield.  A safety can always be bypassed by setting the corresponding limit arbitrarily large or small. For example, if the KR is malfunctioning and reading very low, the KR Lower Limit can be set to 0 or some negative value that it will never reach. Alternatively, there are three override switches, one for the O2 levels, one for the pressure levels and another for the KR. Turing any one or more of these switches to ON will cause the controller to ignore the respective safeties. For example, the same problem with the KR could be addressed by instead turning the KR override to ON without tampering with the lower limit. The “Pressure Override” simultaneously bypasses all four pressure limits and the “O2 Override” simultaneously bypasses both O2 limits.
  
-Unique to the KR override is an additional auto reset switch. When this switch is turned ON, the KR override will stay on only until the reading falls within the range set by the limits or a time delay has elapsed. If the pump has been off for some time, the KR reading will likely have fallen below its lower limit and the pump cannot be restarted without turning the override on. Turning the override on with the auto reset also turned on causes the controller to ignore the reading only temporarilly while the reading is climbing back toward its normal value. The time delay can be configured by clicking on the "Limits and Setpoints" button and going to the "Advanced" tab.+Unique to the KR override is an auto reset option. When this switch is turned ON, the KR override will stay on only until the reading falls within the range set by the limits or a timeout period has elapsed. If the pump has been off for some time, the KR reading will likely have fallen below its lower limit and the pump cannot be restarted without turning the override on. Turning the override on with the auto reset also turned on causes the controller to ignore the reading only temporarily while the reading is climbing back toward its normal value. The length of the timeout period can be configured by clicking on the "Limits and Setpoints" button and going to the "Advanced" tab. Its the field labeled "KR Auto Reset Delay" and sets the maximum time the KR override will remain on. The start of the timeout period is reset whenever the override switch is toggled or when the pump is started.
  
 ===Absolute Limits=== ===Absolute Limits===
Line 135: Line 135:
 In any case, one should avoid letting the pump run unattended with any of the overrides switched to on. As an exception, the KR override can be left on provided its auto reset switch is also on.  In any case, one should avoid letting the pump run unattended with any of the overrides switched to on. As an exception, the KR override can be left on provided its auto reset switch is also on. 
  
-The program itself should be left running nearly 24/7 regardless of whether the pump is on. Even when the pump is off, the program opens and closes the top-up valve to maintain correct pressure in the return manifold. Of course its ok to temporarily quit with dignity and close the program to do computer maintenance such as installing OS updates. However, avoid leaving the program off more than a few hours at a time.+The program itself should be left running nearly 24/7 regardless of whether the pump is on. Even when the pump is off, the program opens and closes the top-up valve to maintain correct pressure in the return manifold. Of course its ok to temporarily quit with dignity and close the program to do computer maintenance such as installing OS updates. However, avoid leaving the program off more than a few hours at a time. Any event in which the program is not running for more than a couple hours at a time, the data analysis team should be notified that pressure regulation was temporarily lost, usually by submitting an ELOG entry.
  
-A known issue with system is the tendency for sensors to hiccup. The voltage output of a sensor as read by the computer will sometime abruptly jump well outside the limit set for the sensor. In these cases, the actual condition at the sensor is ok and there is nothing wrong with the gas system itself. The duration of these hiccups are usually short enough such that they will not pass through the software's low pass filter. However this is not always the case and these hiccups can trigger the pump to go into emergency shutdown. In these cases the pump can be restarted as outlined above.  +When the pump shuts down it's ok to try restarting it as the cause of shutdown may have been an erroneous sensor hiccup. However, if there is a new leak, the o2 levels will remain high and will not start to come down after a few minutes of running. In this case the pump should be turned off as to deter the spreading of O2 from the leak site to other places in the system.
- +
-In any case when the pump shuts down it's always ok to try restarting it as the cause of shutdown was most likely an erroneous sensor hiccup. However, if there is a new leak, the o2 levels will remain high and not come down after a few minutes of running. In this case the pump should be turned off as to deter the spreading of O2 from the leak site to other places in the system.+
  
 If turning on the pump CAUSES any of the pressures to rise outside their limits, the pump should be turned off immediately. This most likely indicates a mechanical blockage downstream of the pump, such as a jammed closed recirculation valve. The over-pressurization caused by running the pump under these conditions could cause a catastrophic failure and hence a huge leak.   If turning on the pump CAUSES any of the pressures to rise outside their limits, the pump should be turned off immediately. This most likely indicates a mechanical blockage downstream of the pump, such as a jammed closed recirculation valve. The over-pressurization caused by running the pump under these conditions could cause a catastrophic failure and hence a huge leak.  
Line 220: Line 218:
 A backup of the Gas Rack folder containing the necessary controller VIs, configuration files and the executable: A backup of the Gas Rack folder containing the necessary controller VIs, configuration files and the executable:
  
-{{:vetoshield:gasrackbackup2015-2-25.zip|}}+{{:vetoshield:gasrackbackupv2015-7-1.zip|}}
  
-The main VI (gas_rack_controller.vi) is in the folder "Controller and SubVIs" folder along with the SubVIs it directly calls. A copy of the exectuable along with the helper files is alongside these files in another folder called "builds". Some of the SubVIs outside the "Controller and SubVIs" folder are also needed while some are just testing VIs.+The main VI (gas_rack_controller.vi) is in the folder "Controller and SubVIs" folder along with the SubVIs it directly calls. A copy of the exectuable along with the helper files are inside the folder called "builds". Some of the SubVIs outside the "Controller and SubVIs" folder are also needed. There are some unused VIs. 
 + 
 +The LabVIEW code was written in LabVIEW 2012. If using the .exe instead of the VI, LabVIEW itself does not need to be installed but you must have the LabVIEW run-time engine (version 2012f3) and DAQmx 9.4.0 installed. 
 + 
 +Also included is the firmware code to program the CPLD located on the control board located inside the blue panel: 
 + 
 +{{:vetoshield:gas_rack_cpld.zip|}}
  
 For additional information on the gas re-circulation system contact Jeff Gunderson at gund0328@umn.edu or 612-669-7962. For additional information on the gas re-circulation system contact Jeff Gunderson at gund0328@umn.edu or 612-669-7962.
Line 248: Line 252:
 {{:vetoshield:mixer_control_board.jpg?700}} {{:vetoshield:mixer_control_board.jpg?700}}
  
-===Programming control=== +The CPLD configuration file is posted at the end of this manual along with the software written in LabVIEW.
- +
-[Joe is currently in the process of finding a copy of the CPLD programming to post right here. Upon repetitive failure to find the copy, this subsection will be omitted.]+
  
 ===Software Control=== ===Software Control===
Line 354: Line 356:
 ====References and Additional Information ==== ====References and Additional Information ====
  
-Here is a backup containing the VIs and the configuration file needed to run the gas mixer. The top level VI is called "Mixer Control 3.vi":+A backup of the Gas Mixer folder containing necessary software needed to run the controller: 
 + 
 +{{:vetoshield:gas_mixer_2015-7-15.zip|}} 
 + 
 + 
 +The main VI (mixer_controllerYYYY-MM-DD.vi) is included along with the necessary SubVIs. A copy of the pre-compiled executable along with a few helper files is alongside these files in another folder called “builds”. Also included are the necessary auxiliary files the controller needs access to which are the three log text files it writes to plus the config file "gas mixer.ini" and the mail list it reads from.  
 + 
 +The LabVIEW code was lasted edited in LabVIEW 2012. If using the .exe instead of the VI, LabVIEW itself does not need to be installed but you must have the LabVIEW run-time engine (version 2012f3) and DAQmx 9.5.1 installed. 
 + 
 +The CPLD firmware is also included: 
 + 
 +{{:vetoshield:gas_mixer.zip|}} 
 + 
 +There is an up-to-date version of the .jed configuration file. The source code included is not the most recent version but is the only version I have been able to find. 
 + 
 + 
  
-{{:vetoshield:mixer_backup12-13-12.zip|}} 
  
-For additional information on the gas mixing system try Joe Pastika at past0035@umn.edu. 
vetoshield/gas.1430153685.txt.gz · Last modified: 2015/04/27 11:54 by jeff

Page Tools