AVC Auto Valve Controller Theory and Operation

Posted on February 15, 2022 by Randy

The AVC (Auto Valve Controller) was developed by PHI (Physical Electronics) in the early 1980s and first appeared on the 5000 series XPS systems. It allowed for automaton of the opening and closing of vacuum valves on the chamber for functions such as loading samples or differentially pumping the ion gun.

The AVC comprises an electronic controller, which drives the pneumatic valves on the vacuum chamber, and a remote box, which provides a way to send requests to the controller and displays the status of the valves on the chamber.

The AVC remote box has 4 buttons:

BACKFILL INTRO

PUMP INTRO

INTRO SAMPLE

DIFF PUMP ION GUN

There are two square buttons on the front of the AVC controller:

ROUGH CHAMBER

BACK FILL CHAMBER

There is a toggle switch on the front of the AVC controller – Auto and Manual. When in the Auto mode, the AVC remote box is used to open and close valves. When in the Manual mode, the little round push button switches on the front of the AVC controller (1 through 8) are active. When you press on any of those buttons the corresponding valve will open. Pressing the button again will close the valve.

The valves on the vacuum chamber are pneumatic right-angle valves and gate valves. The V1 gate valve needs air to open and air to close, most of the other valves need air to open and are spring-loaded closed.

The valve numbers and functions are:

V1 – Gate Valve. Isolates the main vacuum chamber from the load lock.

V2 – Vent valve. Provides 3 PSI of dry nitrogen to the load lock.

V3 – Load lock isolation valve. Isolates the turbo pump from the load lock.

V4 – Differential Pump valve. Isolates the ion gun differential port from the turbo pump.

V5 – Vent valve. Isolates 3 PSI of dry nitrogen from the turbo pump.

V6 – Pre pump valve. Used to pre-pump the load lock

V7 – Pre pump valve. Used to isolate the roughing pump from the turbo pump.

Note that not all systems have the pre pump option and so you may not have V6 and V7. The AVC remote has a schematic that indicates how your system is equipped.

Connections to the back of the AVC controller:

J1 TC1 – Connects to a Hastings DV6M gauge tube that is located on the load lock.

J2 TC2 – Connects to a Hastings DV6M gauge tube that is located on the turbo pump.

J3 Probe – Connects to load lock probe position sensor

J4 Ion – Connects to ion gun remote, normally not used

J5 DIG – Connects to setpoint 2 on the DIGIII ion gauge setpoint relay

J6 Status – not used

J7 208VAC input line voltage

J8 40 pin connector to AVC remote

J9 Up to air – connects to turbo pump controller, lets the AVC know that the turbo pump is ON

J10 Solenoid power – connects to solenoid manifold

J11 Cold Cathode gauge used only on LS systems

Operation

There are two modes of operation, AUTO (automatic) and MAN (manual). The mode switch on the front of the AVC controller sets the mode.

In the Automatic mode the microprocessor in the AVC makes sure that valves open in the correct sequence. For example, the AVC will not open the V1 gate valve to load a sample unless the load lock has been pumped out first.

When operating in the Manual mode the valves will open when the buttons on the front of the AVC controller are pressed. The valves will close when the buttons are pressed again. When operating in the Manual mode, you need to be very careful which valves you open as it is possible to dump the chamber (bring it up to air very quickly) and damage internal components such as filaments and electron multipliers.

Automatic Mode of Operation

Toggle the mode switch on the AVC controller to AUTO.

Load a sample mount:

If your nitrogen is connected to a bottle, make sure that the valve to the nitrogen bottle is open.
Press the BACKFILL INTRO on the AVC remote. V3 will close if not already closed and V2 will open.
Rotate the cap on the load lock so that when the load lock is backfilled with nitrogen to 3 PSI the cap will be able to be easily removed. Sometimes the cap will pop off or flutter from the nitrogen pressure.
Once the load lock is up to air, remove the intro cap then dock the sample mount to the intro arm. Most intro arm probes are magnetic, some of the older systems have a probe that slides between two Teflon seals.
Pull the intro arm all the way back and the sensor switch will close. That will let the AVC know that the probe is in position.
Place the cap back on the load lock but do not twist it tight or you will build up some pressure (3PSI) in the load lock. You can twist the cap tight after the load lock starts to pump out.
Press the PUMP INTRO button on the AVC remote. V2 will close and V3 will open. The turbo pump will spin down and then come back up to speed. If your system is equipped with a Pre-Pump option, then V6 will open and V7 will close. After about 30 seconds V6 will close and then V3 and V7 will open.
As the vacuum improves in the load lock, the bars on the AVC remote box will increase from one to four. After four bars, the fifth bar will come up after 2 minutes. Once you have 5 bars the sample will be able to be loaded into the main chamber. But keep in mind that the longer you pump out, the less water vapor will be introduced as well. I typically recommend 5 bars plus 5 minutes as the minimum amount of time to pump down the load lock before introducing the sample.
Press the INTRO SAMPLE button on the AVC remote box. V3 will close and V1 will open. There will be a pressure burst and then the main chamber should drop into the low 10^-7 Torr to the low 10^-8 Torr range, depending on how long you pumped the load lock and how gassy your sample is. The longer you pump the intro, the lower the pressure burst.
Push the load lock arm in and dock the sample mount to the specimen stage and then retract the intro arm fully. Once the intro arm is all the way out, then V1 will close automatically.

Retrieve a sample mount:

Make sure that the intro arm is all the way back and that the cap is on the load lock.
If V3 is not already open, press PUMP INTRO on the AVC remote and V3 will open automatically.
Wait until you have 5 bars on the AVC remote box, plus a minimum of 5 minutes. For best results you should always be pumping the load lock when not loading samples or differentially pumping the ion gun.
Press the INTRO SAMPLE button on the AVC remote. V3 will close and V1 will open. There will be a pressure burst and then the main chamber should drop into the low 10^-7 Torr to the low 10^-8 Torr range, depending on how long you pumped the load lock and how gassy your sample is. The longer you pump the intro, the lower the pressure burst.
Push the load lock arm in and dock to the specimen stage. Lower the specimen stage down and then retract the load lock arm fully. V1 will close automatically.

Differentially pump the ion gun

Make sure that the turbo pump is on and up to full speed. Some systems have two turbo pumps, one for the intro/load lock and one for the ion gun. If your system has two turbo pumps, make sure that the ion gun turbo pump is on and up to full speed.
Press the DIFF PUMP ION GUN button on the AVC remote. V4 will open and the ion gun will be differentially pumped. You can now set the emission current on the ion gun and open the argon leak valve.

Back fill the chamber

Make sure that the mode switch on the front of the AVC controller is set to AUTO.
Make sure that the card rack power and all electron, ion and x-ray related power supplies are OFF.
Turn off the ion gauge (on most PHI systems that is a DIGIII).
Turn off the Boostivac or DIGITEL 500 ion pump control.
The turbo pump(s) should be ON. This is to prevent the possibility of back-streaming of oil into the chamber.
Press the BACKFILL CHAMBER button. V1 and V2 will open (V3 and V4 will be closed) and the chamber will backfill with dry nitrogen.
Once the chamber has been backfilled (load lock cap can be removed) then you can turn off the turbo pump (s).

Rough the chamber

Make sure that the mode switch on the front of the AVC controller is set to AUTO. The turbo pump(s) should be OFF.
Make sure that all flanges are sealed and that the intro load lock cap is mounted.
Press the ROUGH CHAMBER button on the front of the AVC controller. It will light up red.
Turn on the turbo pump(s).
V2 will close and V1, V3, and V4 will open automatically. The system should pump out to 5 bars on the AVC remote box in about 20 minutes. Continue pumping for another 10 to 20 minutes and then turn on the DIGIII ion gauge controller. You will need to outgas the TSP filaments and wait until you get into the low 10^-5 Torr before starting the ion pumps. Once the ion pumps start (vacuum is in the 10^-6 Torr and improving), you can press ROUGH CHAMBER button on the AVC controller one more time and all of the valves will close.
The system will need to be baked out.

Manual mode of operation

The mode switch on the AVC controller must be set to MAN.

In the AUTO mode the AVC controller uses logic to make sure that valves are opened and closed in the correct sequence. When in the MAN mode, YOU are the logic and you open and close the valves.

Use extreme care when operating the AVC in the manual mode as it is possible to damage the system.

For example, let’s say that you have the load lock up to air and the intro cap is also not mounted on the load lock. All the filaments and high voltages for the controllers are ON. You then manually open V1. What would the result be? The answer – catastrophic failure! You would lose all filaments, probably the electron multipliers, and most likely crack some viewports. So be very careful when operating in the manual mode!

In the manual mode of operation, when you press any of the 1 through 8 buttons on the front of the AVC controller, the corresponding valve will open, except for the vent valve V5. V5 opens and closes automatically when the turbo pump is turned on. If your system is equipped with two turbo pumps, then the V5 vent valve is controlled by the ion gun differential pump turbo.

Here are some examples of when you might want to operate the AVC controller in the manual mode

The DIFF PUMP V4 valve does not open. In this case you can manually press V4 if you know the turbo pump is up to speed. If you have just one turbo pump on your system, then you also need to make sure that V3 is closed before you open V4. After you are done sputtering, you would then need to close V4 before you do something like pump out the load lock.
Roughing the chamber out. You may want to manually open V1 and V3 to pump out the chamber.
Venting the chamber. You may want to manually open V1 and V2.

Finally, here are links to some other blog posts that are related to the AVC –

AVC solenoid replacement procedure

AVC Up to Air relay update

AVC solenoid replacement procedure

Posted on June 9, 2019 by Randy

This procedure describes how to replace the solenoids in the Auto Valve Controller (AVC) used on Physical Electronics PHI surface analysis systems such as XPS Photo-electron and scanning Auger electron spectrometers.

The AVC provides control of the pneumatic valves on the system by using 24V DC solenoids to route air to either open or close the valves as needed. The symptom for a failed solenoid valve is that the light on the AVC remote box indicates that the valve is open, but the actual valve does not open. Or, it may be that the valve will not close.

The function of each valve is listed below:

V1	Gate valve – Isolates load lock from main vacuum chamber
V2	Vent valve – Isolates nitrogen back-fill from load lock
V3	Isolation valve – Isolates turbo pump from load lock
V4	Differential pumping valve – Isolates turbo pump from ion gun
V5	Vent valve – Isolates nitrogen from turbo pump
V6	Pre-pump valve – Isolates mechanical pump from load lock

There are two ways to test the solenoids;

1. Remove the air line (s) to the suspect pneumatic valve and open/close the valve manually. Some valves have two air lines and some have only one. In the case of two air line valves (typically V1 and V4) air should come out of the top air line to the valve when closed, and the bottom airline on the valve when open. If the AVC remote box indicates that the valve is changing states but the air does not change, then the solenoid is most likely bad.

2. You can remove the P10 cable plug from the back of the AVC measure the 24V DC voltage between the pins for the valve in question as shown in the table below. When ON, you will have 24V DC between the two pins for the solenoid in question.

Before you remove the P10 cable you need to close all valves on the AVC remote (V1, V2, V3 and V4) and turn off the turbo pump (s). Also turn off the air to the AVC manifold on the back of the electronic or vacuum console. Usually the air is connected to the console with a quick connect fitting. See Important Notes before turning off the air.

AVC solenoid wire connector info

IMPORTANT NOTES:

When a solenoid is not working properly it is possible and even likely that the vacuum chamber can come up to air during the solenoid replacement procedure.

It is recommended that all valves be closed and the turbo pump(s) turned off before proceeding with the replacement of a solenoid. Note that even though the AVC remote may indicate that a valve is closed, if the solenoid is defective the valve may not actually be closed.

In addition to turning off the turbo pumps, also turn off the card rack power, all electronics, the ion gauge and the ion pump control.

Finally, before proceeding with the replacement of a solenoid, unplug or turn off the air to the back of the vacuum console. Most valves will hold their state (closed) with no air supplied to the valve, but marginal valves may leak when the air is shut off.

Solenoid replacement procedure:

Close all valves on the AVC
Turn off the turbo pump(s)
Turn off the ion gun, electron gun and X-ray source controllers
Turn off the card rack power
Turn off the DIGIII ion gauge control
Turn off the Boostivac ion pump controller
Turn off the AVC main power
Turn off or unplug the air to the back of the console
Unscrew the front panel AVC screws and slide out the AVC controller a little bit
Unscrew the air manifold screws so that you can access the solenoid screws
Unscrew the solenoid that you want to replace. The V1 solenoid is a little bit higher than the other ones and it is located at one end of the air manifold. Starting with the V1 solenoid, the order is V1, V2, V3, V4, V5 and V6.
Cut the wires to the existing solenoid. Make sure that you have enough length for when you reconnect the wires to the new solenoid. Note that the V1 solenoid has 2 sets of wires, upper coil and lower coil. Make sure that you keep the upper coil label on the wires so that you can connect the new solenoid upper coil wires to the correct set.
Cut the wires on the new solenoid to length and strip the ends on the wires that went to the old solenoid and also on the ends of the new solenoid.
Connect the wires together. White to white, black to black (except for V2 which has a yellow wire). You can use twist connects, in line crimp connectors or solder and heat shrink.
Screw the new solenoid into the manifold. Make sure that the black seals on the solenoid line up with the holes in the manifold. Snug the solenoid down firmly but do not over tighten the screws as the manifold is aluminum and it is easy to strip the manifold.
Use tie wraps to tidy up all the wires
Reattach the air manifold to the AVC controller
Make sure that all of the wires on the back of the AVC controller are still connected properly.
Use the front panel screws to reattach the AVC controller to the console.
Turn on the AVC controller main power. All valves on the AVC remote should indicate closed.
Reconnect the air to the back of the console.
Next, see if the ion pump control starts and stays on in the Run mode. If so, the system is still under vacuum.
Turn on the DIGIII ion gauge control and press the I/T 3 button to turn on the ion gauge.

If the ion pumps started and the ion gauge turned on, you should be back in business and can turn on the turbo pump (s) and use the system as you would normally.

If the ion pump control does not start then the system is up to air or partiality up to air. To test the condition of the vacuum inside the chamber, you can pump on the load lock until you have 5 bars and them manually close V3 and manually open and immediately close V1. That will equalize the vacuum in the load lock with the chamber. Now check how many bars you have on the AVC remote box. If 3 or 4 bars then the chamber is only partial up to air and you can just open V3 and V1 and rough the chamber out for 10 to 15 minutes to get into the 10-6 Torr range and then start the ion pumps.Close V1 once the ion pumps start.

If you only have one bar, then the chamber is likely up to air and you should bring the chamber up all the way by back filling with Nitrogen and then pumping the chamber back down. Those procedures are detailed at the bottom of this blog post.

If you have a leaking solenoid and need a replacement, RBD Instruments provides them and our part numbers are listed below. Please contact us for a quotation.

RBD AVC Solenoid part numbers

Description	RBD part number	AVC solenoid designation
V1 24V Solenoid/Auto Valve Control	T062-4E2RE	V1
V2 24V Solenoid/Auto Valve Control	T062E1-3-10-35RE	V2
V3, V4, V5, V6 24V Solenoid/Auto Valve Control	T062-4E1RE	V3, V4, V5, V6

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Here is where you can buy the old style (cylindrical) AVC solenoids –

Warden Fluid Dynamics sold by SunSource

https://www.sun-source.com/Catalog/suppliers/warden

Part

T062-4E1 (V3, V4, V5, V6), vendor p/n T0624E1-24VDC

T062-4E2 (V1), vendor p/n T0624E2-24VDC

T062E1-(V2), vendor p/n T062E1-3-10-35-24VDC

The new style (rectangular) part numbers are:

V1 HA-110-4E2

V2 HA110E1-PSL

V3,V4,V6,V7 HA110-4E1

V5 HA110-4E1

If you need to bring the vacuum chamber all the way up to air, here is the procedure –

System up to air procedure

This procedure will allow you to safely bring the 660 scanning auger system up to air for maintenance.

Shut down all electron, ion and X-ray source power supplies.
Turn off the card rack power
If V4 is open, close it by pressing the Diff Pump Ion Gun button on the AVC remote.
Pump the intro. If you need
Turn off the DIGIII ion gauge.
Turn off the Ion pump control and Boostivac control.
Allow the system to cool for at least 30 minutes. (Or just a few minutes if the electron gun was not on.)
Make sure that the turbo pump is on. If you have more than one turbo pump, they both need to be on.
With the turbo pump on and the intro still being pumped, depress the Backfill Chamber button on the Auto Valve control located behind the vacuum console.
You will hear a hissing sound as air is back-filled into the chamber.
Slightly loosen the intro hatch cover so that when the system is pressurized it will open.
Once the system is vented, turn OFF the turbo pump(s).

System Pump Down procedure

This procedure will allow you to safely pump down the system after being up to air for maintenance.

Make sure that all flanges are secured (use new copper gaskets whenever removing and replacing optics on the vacuum chamber).
With the turbo pump(s) off, depress the Rough Chamber button on the Auto Valve control located behind the vacuum console.
Make sure that the intro hatch is closed.
Turn on the turbo pump(s) by depressing the pumping unit button. You will hear the V2 valve close and the V3 and V4 valves open and the turbo(s) will begin to pump the system out.
After about 20 minutes you should have 5 bars on the Auto Valve control remote. Once you have 5 bars, cycle each of the 4 titanium sublimation filaments for about 2 minutes each at 50 amps on the Boostivac control.
Cycle each filament 2 times, with a few minutes of cool down time between filaments.
After all 4 filaments have been out-gassed, make sure that you still have 5 bars on the Auto valve control remote and then turn on the DIGIII by turning the power switch to UHV and depressing the I/T 3 button.
The DIGIII should indicate in the low 10-3 to mid 10-4 range. Allow the turbo to pump until the system pressure is in the low 10-4 to high 10-5 range, about 30 additional minutes.
Cycle the #1 titanium sublimation filament for about 2 minutes at 50 amps. (Note: If a TSP filament can no longer get at least 45 amps, use the next filament).
When the vacuum is in the low 10-5 range, start the ion pump control by turning the Mode switch to Start. Monitor the 10KV scale. The voltage should be increasing (maximum is about 5.5 kV), and the DIGIII should indicate that the vacuum is dropping into the 10-6 range. (Note that the meter on the Boostivac does not always read, if not then just make sure that you are in the 10-6 range and dropping on the ion gauge).
Once the DIGIII indicates the high 10-6 range, close the V1 valve by depressing the Rough Chamber button on the Auto Valve control located behind the vacuum console one more time. You will hear the V1, V3 and V4 valves close.
On the Auto valve control remote, depress the Diff Pump Ion Gun button to differentially pump the ion gun.
The system vacuum will continue to improve over the next few hours. Cycle the #1 titanium sublimation filament every 30 to 45 minutes to help the ion pumps pull the vacuum down.
Once the base pressure is in the low 10-7 to mid 10-8 range, the system can be baked out to obtain the best possible base pressure.

Hastings RV-16D Vacuum Gauge Repair

Posted on October 16, 2018 by Randy

The Hastings RV-16D thermocouple vacuum gauge is used in the Physical Electronics’ (PHI) Auto Valve Control (AVC) to read the vacuum in the load lock and also at the turbo pump. There are two DV-6M thermocouple sensor tubes connected to the back of the AVC and a relay selects which one is routed to the RV-16D vacuum gauge.

The 0 to 10mV output of the RV-16D (also called the “Hockey Puck” ) goes to a comparator circuit in the AVC and is ultimately displayed on a LED segment graph on the AVC remote. One bar on the AVC remote indicates up to air and 5 bars indicates less than 5 X 10-3 Torr.

When the Hockey Puck in the AVC fails, it is usually because one of the DV-6M thermocouple sensor tubes failed and in turn some of the resistors inside the RV-16D overheated. This blog post will show you how to repair the RV-16D by replacing those failed resistors with higher wattage ones that should be able to survive the next time one of the DV-6M gauges fail.

The layout and schematic below show the resistors that usually fail. R 3 is a 15K ohm 2 watt resistor and R 4 is a 100 ohm 1/2 watt resistor.

Failed Resistors on RV-16D

Failed Resistors on RV-16D schematic

It is recommended that when you replace these resistors that you increase the wattage. For the repairs in the photos below, I used a 15K ohm 5 watt resistor and a 100 ohm 2 watt resistor. These resistors are readily available from Digikey, Newark and Mouser.

And since I already had the RV-16D torn apart I also replaced the capacitor C1 with a new one.

TC gauge before repair

TC gauge after repair

When working on the RV-16D be sure to completely unplug the power to the AVC. I recommend pulling the AVC completely out of the electronic rack or vacuum console. The RV-16D is located in the back left hand corner of the AVC. If your RV-16D has the metal cover on it you will need to remove it and either cut it around the wires or un-solder the wires an feed them through the case. Use your cell phone and take some pictures for reference before you un-solder any wires so that you can be sure to put them back in the exact same place. You do not need to replace the cover, the RV-16D will run cooler without it.

One final note. The schematic is not 100% correct as there is a 49 ohm resistor that is tied across the output on most of the RV-16D gauges that I have pulled apart. I think that this resistor replaces R5 and R6 as R6 is not needed since only the 10mV recorder output is used in the PHI AVC. If your RV-16D does not have the 49 ohm resistor, then I recommend that you add one. It will help to stabilize the output.

49 ohm resistor

If you need technical assistance or parts for the AVC or replacement DV-6M tube please contact us here.

Bonus

Since the AVC was out anyway, I replaced the pots from the RV-16D (R1 , 1 K ohm) and also the bar adjustment pot in the AVC ( R 103 / K6 25 K ohm) to the AVC front panel with 10 turn 2 watt precision potentiometers and also installed an isolated BNC connector to the RV-16D recorder output wires (Blue and black).

This modification makes it much easier to adjust the RV-16D recorder output when you install a new DV-6M tube and to adjust the AVC for 4 bars when the load lock is pump out. The 5th bar on the AVC remote is on a timer and will turn on after the 4th bar stays on for 2 minutes.

With this modification installed it is not necessary to remove the AVC cover to adjust the hockey puck output or the AVC 4th bar.