TSI Instruments MSP TURBO 2950 User manual

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MODEL 2950
TURBOTM LIQUID FLOW CONTROLLER
USER GUIDE
JULY 2021
Patents: www.tsi.com/patents
Prepared by: MSP - A Division of TSI
5910 Rice Creek Parkway, Suite 300
Shoreview, Minnesota, U.S.A. 55126
Phone: [phone]
Fax: [phone]
Internet: www.tsi.com

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REVISION LOG
TITLE:USER GUIDE MODEL 2950 LIQUID FLOW CONTROLLER
DOCUMENT #: 6015650,REV 0
REV
AFFECTED
PAGES
DESCRIPTION
CAPA /
PROJECT
RELEASE DATE
0
ALL
PRELIMINARY RELEASE
D/00380
JULY 2021
COPYRIGHT: ©TSI Corporation; July 2021; all rights reserved
ADDRESS: 5910 Rice Creek Parkway, Suite 300, Shoreview, MN 55126, U.S.A.
TELEPHONE: [phone]
FAX: [phone]
EMAIL: [e-mail]

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Document Approval
Title: User Guide for the Model 2950 Liquid Flow Controller
Document No.: 6015650, rev 0
Approved:
Date:
On behalf of the Product Manager
Date:
On behalf of Safety
Date:
On behalf of the Quality Assurance

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TABLE OF CONTENTS
1 Safety.....................................................................................................................................................................5
1.1 Safety Notations ............................................................................................................................5
1.2 Chemical Safety ............................................................................................................................5
1.3 High Pressure Safety.....................................................................................................................5
1.4 Electrical Safety.............................................................................................................................6
1.5 Fire Safety .....................................................................................................................................6
1.6 Temperature Safety.......................................................................................................................6
1.7 Location.........................................................................................................................................6
1.8 Orientation / Mounting...................................................................................................................7
1.9 Application Safety..........................................................................................................................7
1.10 Installation .....................................................................................................................................7
2 Introduction............................................................................................................................................................8
2.1 Product Description.......................................................................................................................8
2.2 The Design Philosophy .................................................................................................................8
2.3 Principle of Operation....................................................................................................................8
3 Installation and Setup..........................................................................................................................................10
3.1 Location and Mounting................................................................................................................10
3.2 Plumbing......................................................................................................................................11
3.3 Electrical Connections and Cabling.............................................................................................11
3.4 Turning the Power On and communicating with the unit.............................................................13
3.5 Minimizing Gas Pockets & Priming the Sensor...........................................................................13
4 Operating the TurboTM Liquid Flow Controller.....................................................................................................14
4.1 Introduction..................................................................................................................................14
4.2 Configuring and Tuning the Liquid Flow Controller....................................................................14
4.3 Setting and Monitoring the Flow Rate in the Service Tool..........................................................28
4.4 Analog Set Point Signal over Tool Signal (DB9) Port .................................................................29
4.5 Serial Communication over Tool Signal (DB) Port......................................................................30
4.6 Communication over EtherCAT...................................................................................................30
4.7 Status lights.................................................................................................................................31
5 Configurations and Compatibility.........................................................................................................................32
5.1 Piezo Valve Located on the Vaporizer:.......................................................................................32
5.2 2950-V Series Piezo Valve on the Liquid Flow Controller ..........................................................32
6 Maintenance and Service....................................................................................................................................33
6.1 Preventative Maintenance...........................................................................................................33
6.2 Zeroing the Unit...........................................................................................................................34
6.3 Power / Status Light ....................................................................................................................34
6.4 Troubleshooting...........................................................................................................................35
6.5 Service.........................................................................................................................................37
7 Specifications.......................................................................................................................................................37
8 Serial Command Set ...........................................................................................................................................38
9 EtherCAT Command Set.....................................................................................................................................44
Appendix A Mechanical Diagram..............................................................................................................................53
Appendix B Installation, Handling and Warranty.......................................................................................................54
Appendix C Korean EMC Statement.........................................................................................................................55

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1 SAFETY
1.1 SAFETY NOTATIONS
The following safety notations that are used throughout the Liquid Flow Controller user
documentation:
WARNING
Significant potential for serious personal injury may exist if instructions are
not followed correctly. Text appears in Red.
CAUTION
Potential damage to the equipment may occur if instructions are not
followed correctly, but does not present significant potential for serious
personal injury. Text appears in Blue.
NOTE or TIP
Additional information to aid the operator in carrying out the instructions.
No equipment damage or personal injury is likely to occur if the instruction
is not followed. Text appears in Black.
1.2 CHEMICAL SAFETY
Always follow the spill handling procedures indicated in the SDS of the chemicals when leakage or
spill occurs. Check the compatibility of the chemicals with the wetted materials of the Model 2950
Liquid Flow Controller.
The Model 2950 is capable of handling a variety of chemicals. The user is responsible for
verifying that the wetted materials of the controller are compatible with the chemicals being sensed.
These chemicals must also be checked for flammability and the potential of being toxic if inhaled and
the appropriate precautions must be taken. They may also be an irritant to the eyes and skin. Refer
to the Safety Data Sheet provided by your chemical supplier and take the following precautions for
safe and proper use:
Shipment and Dropage Have the Potential to cause damage and leaks
Leakage Test is a Requirement Before Usage
• Always read the Safety Data Sheet
• Avoid contacting chemicals with eyes, skin, and clothing.
• Wear all necessary protective clothing
• Keep chemical containers tightly closed and away from heat and open flame.
• Use chemicals only in a well-ventilated area.
• If you smell chemicals and develop a headache, or feel faint or nauseous, leave the area
immediately. Ventilate the area adequately before returning.
When connecting the controller, follow the guidelines in section 3.2 to avoid leaks.
1.3 HIGH PRESSURE SAFETY
The pressure rating of the Model 2950 depends upon the version of the controller being used. If the
pressure rating is exceeded, the controller may rupture and release the chemical flowing through it.
WARNING: Do not exceed the pressure rating of the controller (see section 5.1)

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1.4 ELECTRICAL SAFETY
The Model 2950 requires connection to a 10-30Vdc single fault power supply. (See "Specifications"
for power requirements.) The primary supply voltage (ex. 120V) must not contact the secondary
voltage (ex. 24V) under a power supply fault. An ‘Information Technology’ supply approved under
the EN 60950 or the UL 1950 standard is recommended.
The controller generates a variable output nominally 25mA @ 130V to control the Piezo Valve.
Exposure to uninsulated electrical voltage or current within the enclosure of the Model 2950 may
result in electrical shock. Only certified technicians should service the 2950.
1.4.1 GROUNDING THE CONTROLLER
The body of the controller should be grounded to minimize the risk of ESD damage or damage from
an accidental power surge.
The 2950 should either be mounted to an electrically conductive grounded panel or a attached to a
mounting screw with an attached ground wire to ensure that the 2950 is properly grounded.
1.5 FIRE SAFETY
The Model 2950 is not designed for use in hazardous locations.
1.5.1 EMERGENCY SHUT-DOWN PROCEDURE
In the event of an environmental catastrophe or any other hazardous equipment condition
that warrants an emergency shut-down, operators are advised to immediately shut down
power to the 2950.
1.5.2 RESTARTING THE SYSTEM AFTER EMERGENCY SHUT-DOWN
Check for the presence of chemical fumes in the area surrounding the model 2950. If
chemical fumes are detected, ventilate the compartment and the area surrounding the
equipment adequately prior to restarting the system.
WARNING: Chemical fumes in heavy concentrations may potentially be ignited when the controller
is powered up, resulting in fire and/or explosion. Do not power up the controller until the area
surrounding the equipment have been adequately cleared of chemical fumes.
1.6 TEMPERATURE SAFETY
The Model 2950 can not withstand high or low temperature extremes and contains several
components that may melt, freeze or rupture if exposed to extreme temperatures.
WARNING: Do not expose the flow controller to extreme temperatures, beyond the stated
operational limits.
Extreme temperatures can cause the controller to rupture and release the chemicals flowing through
it, which in turn might ignite or be toxic.
1.7 LOCATION
The Model 2950 is not designed for use in hazardous locations (per directive ATEX: 94/9/EC).
The risk of explosion needs to be evaluated by the customer. Consider interlocking the flow valves
for any hazardous materials and a warning label saying ‘stay a safe distance while operating’. The
controller should be located in a well-ventilated area away from possible ignition sources.

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WARNING: A chemical leak may create an explosive environment. Follow the appropriate
precautions for hazardous locations. Check the Lower Explosive Limit of the chemical being sensed
and take all precautions necessary.
1.8 ORIENTATION /MOUNTING
The 2950 is factory calibrated in the horizontal position (e.g. laying flat on a table with the inlet/outlet
running horizontally). 2950 mounting orientation does not have a significant effect on flow
measurement or control. After mounting; pressure transducers must be re-zeroed according to
section 6.2
When installing piping connections, care should be taken to avoid supporting the body of the 2950
by the inlet tubing. Mounting holes are provided on the unit to allow proper installation.
1.9 APPLICATION SAFETY
Do not use this product in a medical application, as an emergency shut off or in a safety application
where product failure could result in personal injury. Do not use this product in applications other
than its intended use. Using this product in unintended applications could cause serious injury or
death.
1.10INSTALLATION
Before energizing the 2950, the following items should be checked:
Electrical termination is tight
No leaks are visible at 2950 piping connections

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2 INTRODUCTION
2.1 PRODUCT DESCRIPTION
Liquid precursors are routinely used for
gas-phase processing in microelectronic
fabrication The intention of this product is
to reliably control a liquid precursor at well-
controlled and highly repeatable delivery
rates for thin film deposition processes and
other gas-phase processes used in
semiconductor manufacturing.
2.2 THE DESIGN PHILOSOPHY
The Model 2950 was specifically designed
to work with the PE (Performance
Enhanced) series of TurboTM Vaporizers to
provide a more robust solution for liquid
source vapor delivery, primarily for
Chemical Vapor Deposition applications. It
is designed to quickly, precisely and
repeatably control the flow of liquid or solvent soluble solid precursor at highly repeatable
delivery rate to the TurboTM Vaporizer, so the exact amount of vapor can be delivered to the
process chamber.
In keeping with tight space constraints, the Model 2950 system has a modest footprint, with
overall dimensions of 12.8 cm 5.4 cm 13.9 cm (5.0 in. 2.1 in. 5.5 in.). A dimensional
drawing is provided in Appendix A.
2.3 PRINCIPLE OF OPERATION
The Model 2950 Liquid Flow Controller 2950 LFC works by reading a control signal from a
process tool, which it uses as a set point for a sophisticated PID loop that provides the signal to
the piezo valve on the MSP PE TurboTM Vaporizer. Note the standard 2950 LFC does not have
an embedded control valve. The controller uses the piezo control valve on the vaporizer to
control the flow. Placing the control valve on the vaporizer versus inside the LFC enable a fast
response time, extremely low dead volume, and liquid bubble suppression. The flow rate is
measured by a high precision flow sensor and compared to the setpoint. The flow rate is
determined by measuring the differential pressure across the high precision flow module.
The PID loop tightly controls the output signal to the piezo, by comparing the flow through the
flow controller to the set-point signal and calculates the difference or error. It then uses the
error measurements to calculate the output signal to device being controlled
Where P is a proportional gain factor, I is the integral gain, and D is the derivative gain.
Additional factors are also used in the formula to adjust for offsets and non-linearities.
Default P, I and D parameters can be used, or the PID can be tuned using the 2950 Software
Tool (see section 4.2). Proper tuning will provide a quick response with a small amount of
Figure 1: Model 2950 Liquid Flow Controller

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overshoot using different PID parameters for different flow rate zones and Bias/Offseting/offset
if needed.
Once the flow controller has been tuned, the flowrate can be set, monitored and adjusted using
one of several communication methods. Communication between the 2950 and the outside
world can be done using one of several methods, including RS-485 Serial communication,
EtherCAT, or an Analog Signal.
The output signal is continually adjusted to keep the feedback signal at the same level as the
set point signal.
In order to precisely control the liquid flow rate entering a 28XXPE series Vaporizer, the PID
Loop has a Bias/Offset/Offset function which can be used achieve a quick response with a
minimum amount of overshoot and oscillation.

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3 INSTALLATION AND SETUP
A
RS485/Analog IO Port
J
Firmware Port
B
RS 485 Termination Switch
K
M8 5 Pin Power Connector
C
EtherCAT Ports
L
Power Connector
D
EtherCAT Address Setting
M
Piezo Connector
E
DeviceNet Port (M5)
N
Liquid Outlet
F
DeviceNet Termination Switch
P
Status Light
G
DeviceNet Address Setting
Q
Zero Button
H
Liquid Inlet
3.1 LOCATION AND MOUNTING
When installing the 2950 locate it in a dry well-ventilated area, free of chemical vapors and
combustible gases. At least four ANSI standard #6 screw and washer or ISO standard 4 mm
screw and washer should be used in four of the mounting slots See Appendix A for the
mounting pattern needed. The LFC may be mounted in any position, however. it must be re-
zeroed after installation or orientation change.
Figure 2: Connectors, Switches & Ports on the LFC
H
G
E
C
J
A
L
M
N
D
B
F
K
Q
P

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3.2 PLUMBING
For ease of installation, stainless steel 1/8”
VCR male fittings are used on standard
2950 models. It is a good practice to
check the chemical compatibility of the
tubing and fittings used with the chemical
that is intended to be run through the
tubing and fitting being used. The 2950
was designed to work with a 28XXPE
series TurboTM Vaporizer, with the exit
fitting of the 2950 connecting to the liquid
inlet of a the vaporizer. The piezo valve
on the vaporizer is not meant to be a shut
off valve. Ensure the pneumatic shut–off
valve on the MSP TurboTM Vaporizer is
properly plumbed to prevent undesired
chemical flow.
When plumbing the 2950:
Always use two wrenches when
tightening/loosening any connections;
finger tighten all the nuts; then use two
wrenches, but only one hand to tighten
the nut. With this technique,
unnecessary torque on the fitting will
be minimized.
Avoid any over-torque on the liquid
line connections so that nearby welded
joints are not stressed. Pay particular attention to the stems at the inlet and the outlet.
Tightening fittings requires an experienced, careful hand. When in doubt, try less torque
rather than more. If a leak is observed, only then should you use additional torque.
Use gasket of appropriate material
Refer to the following manufacturer’s installation instructions:
VCR Fittings (Swagelok): Catalog No. MS-13-150, PAGE 27, or equivalent catalog.
3.3 ELECTRICAL CONNECTIONS AND CABLING
Serial communication is done through the DB9 connector on the top of the unit. The piezo
cable included for connecting the Liquid Flow Controller
to the Piezo Valve on the Vaporizer is a one (1) meter
long cable (MSP part number 7004400). If a different
length is needed, please contact the factory. The basic
connections that are needed for the unit to function are
the power and piezo connections.
CAUTION: To prevent damage to the Liquid Flow
Controller and other components, make sure that there
is no power to the Liquid Flow Controller when
connecting cables.
3.3.1 POWER CONNECTION
There are two power connectors on the 2950. Power needs to be supplied to one OR the
other. Do not connect power to both connectors. DC power should only be supplied to the
2950 from a clean local power source. The 2950 is a Class A EMC device (please see
Figure 3: Connecting 2950 to a 28XXPE Vaporizer
Figure 4: Power Connectors
To Liquid Pressure
Vessel
Tube from
Controller to the
liquid inlet of the
vaporizer
Piezo Cable
M8
Screw
Terminal

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Korean EMC statement in Appendix C.
• All DC power cables shall be less than 3m long
• DC power shall not be supplied from a DC distribution
network.
One power connector option is a screw terminal connector
6015007 (Phoenix Contact PN: 1757019).
The second power connector option is an M8 with the following pin out. (ref: ETG.5003.2020
section 5.3.4). One possible M8 EtherCAT Power cable is the Omron XS3M-M524-10.The
pin out of the M8 connector and the screw terminal
connectors are as follows:
3.3.2 PIEZO VALVE CONNECTOR /PID OUTPUT
The 2950 Liquid Flow Controller uses a Proportional-Integral-
Derivative (PID) loop to control voltage to the piezo valve on
a PE series vaporizer. This connector drives the Piezo valve
on the 28XX PE series of Vaporizer. The pin out is in the
following table.
The standard 1 meter long cable is part number 7004400.
3.3.3 SERIAL PORT
The 2950 receives and sends analog signals and / or serial communicates through a DB9
connector located at the top of the 2950.
Communication through the serial port is
needed to add, delete or modify liquids being
used in the Flow Controller (see section
4.2.2).
The 2950 senses or receives a 0 to 5V or 0
to 10V (depending upon how it was
configured) analog signal from the user’s tool
between pins 4 and 5 (see table 10).
The signal
from the
user’s tool is interpreted as a proportional signal ranging
from 0% of full scale (corresponding to 0V) to 100% of full
scale (corresponding to a 5 volt signal). The input
impedance between a pair of Set-point Input pins (6 & 7) is
35 kΩ. The pinout of the connector is described in Table 9.
The Liquid Flow Controller also indicates that liquid is
flowing through it, with a proportional signal between the
Monitor Output pin (pin 8) and corresponding Return pin
(pin 9). The signal ranges from 0 volts (indicating no flow)
to 5 volts ( indicating a maximum flow) for a given
configuration of Flow Controller. The DB9 cable used should be shielded.
Pin
Description
1
+24V
2
not connected
3
Power Common
4
not connected
5
not connected
Table 5: M8 pin out
Figure 6: Location of Piezo
Valve
Pin
Description
1
0 - 0130Vdc Output
2
Return
Table 7: Piezo Pin Out
Figure 8: Location of Serial Port
Pin
Function
1
RS-485 (A+)
2
RS-485 (B+)
3
RS-485 ground
4
0-10V Valve Signal (Out)
5
Ground / Return
6
0-5V Setpoint Input
7
Ground / Return
8
0-5V Flow Monitor Out
9
Ground / Return
Table 9: Serial Port Pin Out
Serial Port
Piezo Valve
Connector

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Be sure that the RS485 termination switch is in the ‘ON’ position to minimize errors in
communications (see letter B, Figure 2)
Note: All of the return pins are internally connected.
Section 4.2 describes how to configure and PID tune the Liquid Flow Controller, including the
parameters needed to establish communications. Since many computers have a USB port
instead of an RS485 port, a option for a USB to
RS485 converter is the Ulinx model number
485USBTB-2W-LS-A.
3.3.4 ETHERCAT CONNECTIONS
After the unit is set up, EtherCAT connections can
be made. A shielded RJ45 cable (CAT 5 or CAT 6)
should be used (for example: Harting
09474747014) to connect the 2950 LFC to the
EtherCAT network.
Use a properly grounded ESD strap when connecting cables to the 2950 LFC.
3.3.5 FIRMWARE UPGRADE CONNECTION
The UART port is used for firmware upgrades and is located on the side of the flow controller.
It is letter J in Figure 2. It is for factory use only.
3.4 TURNING THE POWER ON AND COMMUNICATING WITH THE UNIT
Before initially powering the controller, be sure that the tool output signals to the 2950 are in a
safe state, either disconnected from the tool or properly grounded to prevent a run-away
controller output (for example: if the 2950 is used with a PE version of an MSP Vaporizer, make
sure that the shut off valve is closed.) After the Liquid Flow Controller is properly wired and
ready to be powered up, then communication can be established.
3.5 MINIMIZING GAS POCKETS &PRIMING THE SENSOR
Gas trapped inside the
2950 LFC can cause poor
performance of the
differential Pressure
Liquid Flow Controller
(2950 LFC), such as
longer response times,
reduced accuracy and
erratic behavior.
To eliminate gas pockets
in the 2950 LFC, a
vacuum should be applied
for several hours to the
exit port to remove any
unwanted gas in the unit
and the lines going to the
unit before running fluid
through the Liquid Flow
Controller (as shown in Figure 11).
Figure 10: Location of EtherCAT Ports
Figure 11: Evacuating the 2950LFC
EtherCAT Ports
Port

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When the 2950 LFC is
connected in-line with a
2950 LFC Vaporizer, a
valve upstream of the
2950 LFC can be shut,
and the pneumatic shut
off valve and piezo
valve opened to allow
the downstream vacuum
to pull out all the gases
trapped in the 2950
LFC.
After the 2950 LFC has
been evacuated, close
the piezo valve and the
pneumatic shut off valve
on the vaporizer. Then
open the valve
upstream of the 2950 LFC and allow the liquid to fill the vacuum in the 2950 LFC to draw liquid
into it and prime the unit.
4 OPERATING THE TURBOTM LIQUID FLOW CONTROLLER
4.1 INTRODUCTION
The model 2950 TurboTM Liquid Flow Controller is designed to work with the 28XX PE series
TurboTM Vaporizers. It comes pre-programmed with one or more liquids calibrated at the
factory or service center, with vaporization in mind.
4.2 CONFIGURING AND TUNING THE LIQUID FLOW CONTROLLER
The 2950 LFC can be configured and PID tuned after it has been connected (ref: section
3.3.3) to a computer using the MSP 2950 Configuration Tool software. The software is
available in the My Account portion of the TSI web site (www.tsi.com). After creating an
account on the TSI web site, register your 2950 LFC in the My Instruments section (using the
serial number) to access the software.
Figure 12: Priming the 2950 LFC
Evacuation
Priming
• Close the Shut off Valve upstream of the 2950
LFC
• Close the Piezo Valve
• Open the Pneumatic Shut off Valve
• Close the Pneumatic Shut off Valve
• Open the Piezo Valve
• Open the upstream shut off valve
• Wait until the vacuum pulls the gas out of the
2950 LFC
• Allow the vacuum in the 2950 LFC to draw liquid
in.
Table 13: Summary of Evacuation & Priming Procedures

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It is designed to run on a computer that meets the
following requirements.
Operating system: Windows 7 or greater
Speed: At least 2 GHz of processing speed
Communication: Serial communication (USB port or
DB 9 Port)
Framework: Dot Net Framework 4.6.0
The communications parameters are in Table 13.
Use a properly grounded ESD strap hen connecting cables to the 2950 LFC.
4.2.1 PRODUCT OVERVIEW TAB
Figure 16: Product Overview Tab
When the 2950 Service Tool is started, it opens to the Product Overview tab. The product
overview tab displays the basic information about the unit connected to the 2950
Configuration Tool, including the model number, serial number, firmware version etc, which is
read from 2950 (ref: Error! Reference source not found.).
Communications can be established using the Controller Pull Down Menu. The essential
items that need to be set are in the other tabs. They include selecting the liquid and entering
the PID tuning parameters.
Figure 14: Location of RS485
Termination
Parameter
Value
Baud Rate
115,200
Data Bits
8
Stop Bits
1
Parity
None
Table 15: Serial Parameters
RS485
Termination
Switch

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4.2.2 ESTABLISHING COMMUNICATION
After a cable is
connected to the
serial port, select
the Controller pull
down window and
select Connect.
The Connect pop
up window then
appears (ref: Figure
17). Select the
com port from the serial port pull down window and click the ‘Ok’ button.
4.2.3 FLOW TUNING TAB
The flow tuning tab is where the tuning parameters are entered and tuned.
Figure 18: Flow Tuning Tab
In normal steady state operation, the output signal sent to the piezo valve is determined by the
following simplified formula.
             
The error is the difference between the setpoint and the sensor signal. The sum of errors is the
sum of all errors () that occurred plus the initial Bias/Offset value. The change of error
() is how much the error has changed in the most recent iteration. As the system
approaches steady state, the error goes to zero and the change of error goes to zero, so the
output is dominated by the sum of errors and the integral factors.
The goal of tuning the Liquid Flow Controller (LFC) is to minimize overshoot, minimize
response time and to dampen pressure spikes. However there is often a trade-off between
these parameters.
Bias/Offseting and the Multi-point Tuning Window will allow the system to quickly reach steady
state flow. Once the system is close to steady state flow, it uses the PID values in the
Figure 17: Establishing Communication
Recipe Table
Multipoint Tuning
Parameters
Real Time Data
Parameters
Save Table
Zero
Transducer
Piezo
Configuration
Stream
Flow Button
Flow Control
Parameters

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Bias/Offset table to adapt to minor disturbances in the system and adjust the output signal
accordingly.
To test the effectiveness of the tuning, the ‘Stream Flow Screen’ can be used.
4.2.3.1 Loading or Saving the Recipe Table
When communication is first established, the tuning
parameters that are on the 2950, are uploaded to the
computer and displayed in the Flow Recipe Table. The
Liquid Calibration parameters are also uploaded and
available under the Liquid Configuration tab. A Recipe
Table can also be loaded by selecting the Controller pull
down menu and selecting ‘Read Flow Recipe Table’
(see Figure 19). In addition to the Current Liquid
parameters
that are
loaded, parameters for additional liquids stored on
the 2950 are also loaded into the Service Tool.
4.2.3.2 Recipe Table
Up to eight zones can be entered into the recipe table. The eight zones are numbered 0
through 7 on the left side of the table. The parameters being set in each zone are the
Threshold, Proportional Gain, Integral Gain, Derivative Gain, Bias/Offset Voltage and
Bias/Offset Time. Each zone corresponds to a range of set points based upon the threshold
value.
Threshold: corresponds to the upper most setpoint for the zone. It is a number ranging from
0.0% of full scale to 100.0% of full scale. In a given row, the threshold is the upper limit of the
range of user setpoint that the PID parameters in that zone will be used for. The lower limit is
the threshold of the zone below it on the table. For zone 0, the lower limit is 0% of full scale
flow.
Note: the full scale for a given liquid is found in the Real Time Data parameter section.
For example, if the threshold for zone 0 is 15 and the threshold for zone 1 is 30, then if the
setpoint is 25 the PID parameters of zone 1 would apply.
Proportional Gain: is the proportional value used in PID loop, while the controller is in PID
Mode.
Integral Gain: is the integral value used in PID loop, while the controller is in PID Mode.
Derivative Gain: is the differential value used in PID loop, while the controller is in PID Mode.
Figure 19: Location of Piezo Valve
Figure 20: Reading the Flow Recipe Table
Figure 21: Flow Recipe Table
Select this
to Load the
recipe table

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Bias/Offset Voltage: is the piezo voltage that is used for the Bias/Offset Time when the set
point is changed from zero to a value in the corresponding zone. These values are located in
the Bias/Offset column of the Flow Recipe table (ref: Figure 21). If no Bias/Offset is desired,
set the Bias/Offset Time to 0. For more details on how to use Bias/Offseting read section
4.2.3.3
Note: this value is only applied if the “Use Table Bias/Offset Value” click the value selected.
Otherwise one of the Stored Bias/Offset Methods are used, either Current or Alternate.
Note: If 0V is sent to the piezo-valve on a 28XX series vaporizer that corresponds to the
valve being fully open and a voltage between 100V and 120V (depending upon how it is
tuned) corresponds to the valve being fully closed.
Bias/Offset Time: is the amount of time the Bias/Offset voltage is applied when the setpoint is
changed from zero to a different value. The units of Bias/Offset time are milliseconds and it
ranges from 0ms to 9999 ms.
Dynamic Bias/Offset Adder: although this parameter is in the Table, it is only used when the
Bias/Offset Source is set to Dynamic rather than Recipe Table. This value is applied to the
stored Dynamic Bias/Offset, to allow the piezo to be more closed (positive value) or more open
(negative value) than the last stored operating voltage. The Dynamic Bias/Offset Adder voltage
is generally set at 1 or 2 volts. The Dynamic Bias/Offset Adder can be applied to compensate
for overshoot,
Save Table Button: After the values in the table have been changed. The Save Table Button
needs to be clicked for the values in the table to be sent to the Liquid Flow Controller.
4.2.3.3 Multipoint Tuning Parameters - Bias/Offsetting
The multi-point tuning box is where the user selects the Bias/Offset Method used and the
parameters used if a Dynamic Bias/Offset Method is used by the liquid flow controller.
The goal of Bias/Offsetting is to reach the desired flowrate as quickly as possible, while
minimizing the downsides of a traditional control loop. The Bias/Offset Method used can
reduce the response time, overshoot, oscillations and settling time. It does this by setting the
output signal to predetermined value (Bias/Offset voltage) determined to match a given flowrate
in a given zone, for a short period of time (the Bias/Offset Time). After this time expires control
is turned over to standard PID loop.
The Bias/Offset Voltage is determined by one of three methods determined by the Bias/Offset
Source and Store Method Settings.
The first method uses Bias/Offset values entered by the user and stored in the Recipe Table.
Figure 22: Dynamic Bias/Offsetting Concept
In Dynamic Bias/Offsetting, the
data collected during one flow
pulse is used to provide bias
voltage to the next pulse.
Flow Pulse

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The other two methods are Dynamic, where the Bias/Offset voltage is determined by using
data collected the last time the setpoint was operating in a given zone. Dynamic Bias/Offset
also provides improved response time. When Dynamic Bias/Offset is chosen, the Bias/Offset
Value is determined by either the Current Method or the Alternate Method.
The Current Method stores the last piezo voltage one half second before the trailing edge of
the flow (before the set point was changed to zero).
The Alternate Store Method stores the piezo voltage at the time stability is first achieved.
Stability is determined by using the Stability Threshold (% of full scale) and Stability Interval
(number of cycles inside the threshold window) entered by the user, which are described
below.
Stability Interval: for the Current Method is a fixed interval one half second before the flow is set
to zero. For the Alternate Method, it is a variable interval after the setpoint before stability is
declared. Stability is declared by summing the absolute value errors for each PID cycle and if
the resulting error sum is less than a Stability Threshold then it is considered stable.
The graph in Figure 23 illustrates the previous concepts
Figure 23: How Dynamic Bias Offset values can be determined
Bias/Offset Source Pull Down: is used to switch between
using Bias/Offset voltages from the recipe table (by selecting
Bias Source as Recipe Table) or using a Dynamic Store
Method (by selecting the Bias Source as Dynamic). If no
Bias/Offset is desired then select the Bias Source as Recipe
Table and set the Bias/Offset Times in the Recipe Table to
zero (0).
Store Method: is either Current or Alternate. Current uses
the last voltage applied to the piezo, before the setpoint
switched to zero, while the Alternate method uses the voltage
applied just after the flowrate stabilizes as determined by the
Stability Interval and Stability Threshold.
Stability Interval: is the number of PID intervals over which the PID needs to be stable before
the Bias/Offset is saved. The stability function adds up the absolute value errors of each PID
cycle during the Stability Interval.
Stability Threshold: is the average error under which the PID is considered stable. The default
is 2% and the acceptable range is between 0% & 100% of full scale. The Stability Threshold is
generally 1% to 2% of setpoint.
Dynamic Bias Offset Adder:
Dynamic Bias/Offset tends to cause flow overshoot by causing the valve to open too quickly.
To compensate for this overshoot, the Dynamic Bias/Offset Adder can be applied. The
Figure 24: Multi-Point Tuning

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Dynamic Bias/Offset Adder voltage is generally set at 1 or 2 volts and can be entered by the
user in the Flow Recipe Table (Figure 21). This value is applied to the stored Dynamic
Bias/Offset to allow the piezo to be more closed (positive value) or more open (negative value)
than the last stored operating voltage.
For example if the flow controller determined and stored a Dynamic Bias/Offset of 64 volts for a
zone 0 and the Bias/offset Adder is set to 2 volts then the piezo output for the next cycle in
zone 0 will be 62 volts for the Zone 0 bias time. This will start the piezo valve to be more
closed to limit overshoot in the next cycle.
Each time the setpoint is set to a value in that zone afterwards, that Dynamic Bias/Offset will be
used as the Piezo Voltage for the Bias/Offset Time.
Apply Settings: To send the settings in the Multipoint Tuning box to the Liquid Flow Controller,
the Apply Settings box needs to be clicked.
4.2.3.4 Real Time Data
The parameters in the Real Time Data Box are updated in
real time after the Stream Flow Button is pressed. To see
a graph of the parameters in Real time, the Data Window
can be opened and used as described in section 4.3
Full Scale Flow: displays what the maximum settable
flowrate for the 2950 LFC, with the liquid currently selected.
Digital Setpoint: displays the value of the digital setpoint in
the 2950 LFC
Analog Setpoint: displays the value of the analog setpoint
that the 2950 LFC received from the serial port, in the form
of a 0 to 5 volt signal (where 5 volts is full scale) or from 0 to
10 volts (depending upon how the unit was set up). The analog voltage read by the 2950 is
converted into grams per minute based upon the parameters of the liquid selected.
Measured Flow: displays the current flow measurement with units of grams per minute
Piezo Voltage: displays the voltage being supplied to the piezo connector
Temperature Average: displays the current average
temperature value from the two internal temperature sensor
Pressure Sensor 1: displays the pressure in kPa from the
upstream pressure sensor
Pressure Sensor 2: displays the pressure in kPa from the
downstream pressure sensor
Differential Pressure: displays the pressure difference between pressure sensor one and
pressure sensor 2 in units of kPa.
Stream Flow Button: Clicking this button starts and
stops data being collected by the 2950 and sent to the
Service Tool.
4.2.3.5 Flow Control Functions
Mode: is used to select how the piezo voltage is
calculated.
AnalogSetpoint will use an analog signal from the
Figure 25: Real Time Data
Figure 26: Stream Flow Button
Figure 27: Flow Control Box