Auto Valve Control adjustment procedure

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The Auto Valve Control (AVC) controls all of the air valves on many PHI systems. It has built in logic that uses two thermocouple sensors and a mechanical switch to determine the status of the system.

There are four common problems with the AVC:

1. The V4 ion gun valve will not open in the automatic mode.

2. The gate valve will not close when the probe is retracted.

3. The V1 led on the remote is neither Red (closed) nor Green (open).

4. One or more of the solenoids stick, or leak.

Problems/Solutions:

1. The V4 ion gun valve will not open in the Automatic mode.

There are two thermocouple gauge tubes that sense the vacuum of the turbo(s), but only one TC gauge. TC1 is located on top of the turbo and determines whether or not the turbo pump is up to full speed. TC2 is under the tabletop and measures the vacuum in the intro chamber. If the intro pumps down to 5 bars but the V4 valve will not open, either the TC gauge is out of adjustment, or TC1 is defective.

To adjust the TC gauge:

1. Remove the cover on the AVC and slide it out enough to work is able to access inside of the unit. On some systems, such as the 600 Multiprobe, you can remove the tabletops and come from the top down. On other systems, such as 5000 series XPS systems, you will need to slide the AVC out of the rack a little bit.

2. Refer this adjustment to qualified personnel. With a DVM, measure the voltage on pins 1 and 2 of P14. This is the connector that comes from the TC gauge control output. Pump down the intro. After you have 5 bars, you should have 9 to 10 mV DC on pins 1 and 2 of P14. If not, there is a pot on the back of the TC gauge (hockey puck) that needs to be adjusted. There is a hole on the back of the AVC that might allow you to do the adjustment from the back of the AVC with a long, thin screwdriver. Usually this does not line up and you need to remove the 3 screws at the base (under side of the AVC) that hold the TC gauge to the AVC and rotate the TC gauge up to get to the pot. Adjust the pot for 9 to 10 mV. It goes from Zero mV (air) to 10 mV (vacuum). CAUTION! If you have to move the TC gauge exercise extreme caution! There is a 220-volt AC terminal strip located near the TC gauge. It is recommended that the AVC be shut down (close all valves and turn off all turbo pumps first) and un-plugged before tilting the TC gauge. Touching the metal case to the exposed 220-volt AC terminal strip will cause arcing, damage to the AVC and possible electrical shock!

AVC-control-board

AVC-control-board

NOTE:

RBD provides an upgrade to AVC units where the P14 and TG guage pots are mounted on the front panel of the AVC. We install this upgrade as part of a standard AVC repair.

3. After you have the TC gauge adjusted for 10 mV, adjust R103 (The only adjustment pot in the AVC) for 4 bars on the AVC remote. The fifth bar is timed and comes up automatically after two minutes, provided that the vacuum stays at 4 bars. Find the threshold for 4 bars, and turn it an additional 1 full turn. There is some hysteresis in the adjustment.

Calibration of the TC gauge is now complete. If the V4 valve still does not open in the automatic mode, then the Thermocouple tube TC1 located on the turbo is most likely defective or out of range. Since there is only one controller, both of the thermocouple tubes need to be matched somewhat closely in performance.

You can purchase these tubes from RBD, our part number is DST06MRE.

2. The gate valve will not close when the probe is retracted.

If the V1 gate valve does not close automatically after retracting the intro probe, most likely the intro probe switch is broken.

1. Remove the probe bnc cable from the intro (located under the intro chamber near the pumping line).

2. Short the center pin on the cable to the outer shield on the cable.

3. V1 should now close. If so, then the intro probe switch is broken and needs to be repaired/replaced.

You can operate the intro by shorting the cable to close the V1 valve until it is convenient to remove the intro from the gate valve and repair/replace the switch (make sure the turbo pump is OFF before you remove the intro). PHI’s part number for the switch is 613174. You can also usually repair or replace these with a piece of spring steel for much less than the price of a new switch.

If you have a magnetic load lock arm then sometimes the magnetic sensing switch can fail. If so, contact RBD for a replacement.

3. The V1 led on the remote is not Red (closed) or Green (open).

Sometimes when there is a power outage the AVC will not be re-set properly unless the probe is fully retracted first.

1. Make sure that all valves are closed.

2. Pull the probe all the way out.

3. Make sure that the AVC is in the Automatic (not manual) mode.

4. Turn the AVC off.

5. After one to two seconds, turn the AVC back on. Do not leave it off too long or the turbo pump will vent.

The V1 light should now be red. If not, there is a problem with the AVC. Contact RBD Instruments for assistance at (541)330-0723 or at rbdinstruments dot com

4. Any one of the valves sticks, does not open, or leaks.

After some number of years, the solenoids that drive the air-actuated valves become dried up. The result is intermittent operation. Sometimes the valves will stick open, other times closed. You can take the solenoids apart and lubricate the seals with vacuum grease. This is somewhat difficult to do and can result in the valve being totally inoperable. The best solution is to replace the defective solenoid with a new one. RBD has these parts in stock at all times.

The RBD part numbers are:

V1 Solenoid     T062-4E2RE

V2 Solenoid     T062E1-3-10-35RE

V3,4,5,6  Solenoid     T062-4E1RE

avc-solenoid-part-numbers

avc-solenoid-part-numbers

 

Pfeiffer Duo 1.5 pump rebuild procedure

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If you have an older Balzers Pfeiffer Duo 1.5 mechanical pump that needs to be rebuilt and want to do it yourself, here is a link to a detailed procedure:

http://www.rtftechnologies.org/general/pfeiffer-duo15a.html

pfeiffer-duo-mechanical-pump
pfeiffer-duo-mechanical-pump

For parts or rebuilding of Pfeiffer Duo 1.5 mechanical and turbo pumps, here are some companies that we have used with success:

http://www.pchemlabs.com/services.asp

https://www.ajvs.com/new/product_info.php?products_id=12557&category_id=0

Calibrating the 9103 USB Picoammeter

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9103 Picoammeter

Calibrating the 9103 USB Picoammeter

The calibration procedure provided with the 9103 USB Picoammeter is written for use with a Keithley 220 current source and is set up for semi-automatic operation. But what if you want to use another brand or type of current source? The following procedure shows you exactly how to calibrate and verify calibration using any current source.

Preparing for Calibration

In order to calibrate your 9103 Picoammeter, you will need a calibrated current source, and software that can send / receive ASCII commands to the Picoammeter. If you are using the Actuel application supplied with your Picoammeter, there is a built in console window that allows you to communicate directly with the Picoammeter using ASCII commands – simply click the Console button to open the window and type the commands in the field provided.

Note that when using Actuel’s console window, the ampersand character “&” that precedes all commands is automatically entered for you – you do not have to type it.

Note also that the offset and gain calibration apply to all 7 ranges. Range 1 corresponds to the highest resolution range in nA, range 7 corresponds to the lowest resolution range in mA. The Gain Reference Table (at the end of this article) shows the ideal calibration values and limits for each range (both positive and negative polarity).

Perform OFFSET Calibration and Verification Calibrate Offset (all ranges)

  1. Ensure that the current input is disconnected
  2. Send command &R0 (auto-range)
  3. Send command &C1, 9103 responds “Offset Calibration starting…”
  4. Wait for completion (about 30 seconds), until message received “Offset Calibration Completed!”
  5. Send command &C0, 9103 responds “OPEN CIRCUIT Offset Calibration starting…”
  6. Wait for completion (about 30 seconds), until message received “OPEN CIRCUIT Offset Calibration Completed!”

Verify Offset for (all ranges)

  1. Ensure that the current input is disconnected
  2. Send the &I0500 command to start receiving data samples
  3. Send command &R# (where # is a number 1 through 7) to manually select the range to be verified (see the Gain Reference Table below)
  4. Verify measured values received are zero and have at least 1 zero after the decimal point
  5. Repeat until all ranges are checked

Perform GAIN calibration

Refer to the Gain Reference Table below for interpretation of the current values and limits.

  1. Send the &+CC command to unlock the calibration function. The green LED will begin flashing
  2. Connect the current source to the 9103 input
  3. Turn on current source. Ensure current source is at proper operating temperature before proceeding
  4. Send command &C2, and wait for prompt from 9103: “Apply test current…”
  5. Using your calibrated current source, input the specified test current (see table below) and send command &C2 again, the 9103 will respond with “Measuring and calibrating gain…”
  6. Repeat the current application for each of the 7 ranges and polarities, following the prompts provided by the 9103
  7. Wait for response from the 9103: “Gain Calibration completed!”

Perform GAIN verification

  1. Send command &R0 (select auto-ranging)
  2. Send command &I0500 (sample interval 500 mSec)
  3. For each test current (shown in the Gain Reference Table below), set the source to the specified current and select the appropriate current range on the 9103 in turn (&R1, &R2, &R3, &R4, &R5, &R6, &R7), monitoring the data stream for at least 10 seconds after each range, and ensuring that the readings are stable in each range (if a message starting with &S* appears indicating an unstable value, wait a little longer)
  4. Verify that the measured value reported by the 9103 is within 1% of the set current for each range
  5. Send command &I000 to stop sampling
  6. Disconnect current source and turn off the 9103 – calibration is complete

Gain Reference Table
(14 test currents are shown, positive/negative polarities for each of the 7 ranges)

Range

Test Current

9103 Value

9103 Value Limits

1

+ 1.0000 –9

1 nA

0.9900, 1.0100 nA

2

+ 10.000 –9

10 nA

09.900, 10.100 nA

3

+ 100.00 –9

100 nA

099.00, 101.00 nA

4

+ 1.0000 –6

1 uA

0.9900, 1.0100 uA

5

+ 10.000 –6

10 uA

09.900, 10.100 uA

6

+ 100.00 –6

100 uA

099.00, 101.00 uA

7

+ 1.0000 –3

1 mA

0.9900, 1.0100 mA

1

– 1.0000 –9

– 1 nA

-0.9900, -1.0100 nA

2

– 10.000 –9

– 10 nA

-09.900, -10.100 nA

3

– 100.00 –9

– 100 nA

-099.00, -101.00 nA

4

– 1.0000 –6

– 1 uA

-0.9900, -1.0100 uA

5

– 10.000 –6

– 10 uA

-09.900, -10.100 uA

6

– 100.00 –6

– 100 uA

-099.00, -101.00 uA

7

– 1.0000 –3

– 1 mA

-0.9900, -1.0100 mA