Halma MC Series User manual

OPERATING MANUAL
FOR MASS FLOW CONTROLLERS
Models MC · MCD · MCE · MCQ · MCR · MCS · MCV · MCW

2 Introduction
Thank you for purchasing your mass flow controller.
If you have any questions, or if something is not working as
expected, please contact us. We are eager to help you in
any way possible.
Contact Information
World Headquarters,
Tucson, Arizona, USA
[e-mail]
alicat.com
7641 N Business Park Dr.,
Tucson, AZ 85743 USA
[phone]
Europe
[email protected]om
Geograaf 24
6921 EW Duiven
The Netherlands
+31 (0)26 203.1651
China & SE Asia
[e-mail]
alicat.com.cn
2nd Floor, Block 63, No. 421,
Hong Cao Rd,
Shanghai 200233
PRC
[phone] ext. 801
India
[e-mail]
Halma India Pvt. Ltd.
Plot No . A-147, Road No. 24,
Next to Spraytech Circle
opp. Metropolitan Company,
Wagle Industrial Estate
Thane-West
Mahārāshtra 400 604
[phone]
Recalibrate your mass flow controller every year.
Annual calibration is necessary to ensure the continued accu-
racy of readings, and to extend the Limited Lifetime Warranty.
Fill out the Service Request Form at alicat.com/service,or
contact us directly when it is time to send in your device for
recalibration.
For devices ordered with CSA, ATEX, ISO 17025, or
other certifications, please visit alicat.com/certifications.
For information about our limited lifetime warranty, visit
alicat.com/warranty.
Serial #:
Next Calibration:
This device comes with a NIST-
traceable calibration certificate.
This device conforms to the European
Union’s Restriction of Use of Hazardous
Substances in Electrical and Electronic
Equipment (RoHS) Directive 2011/65/EU.
This device complies with the
requirements of the Low Voltage
Directive 2014/35/EU and the EMC
Directive 2014/30/EU and carries
the CE Marking accordingly.
This device complies with the
requirements of the European Union’s
Waste Electrical & Electronic Equipment
(WEEE) Directive 2002/96/EC
DOC-MANUAL-MC Rev 4, 2021.05.25
MC10SLPM
MCV1SLPM
MCS10SLPM
MCES2SLPM

2021.05.25  REV. 4  MASS FLOW CONTROLLER OPERATING MANUAL 3
Introduction
Your new flow controller has a variety of innovative
features:
• High-accuracy performance for all your gases.
Use your flow controller with any of the 98+ gases
included with Gas Select™, page 18.
• Control pressure while monitoring flow rate.
Set the closed loop control algorithm to pressure
control, page 15.
• 1000 readings per second guarantees high
resolution data, page 21.
• Monitor live pressure and temperature during
flow control, page 10.
• Backlit display with adjustable contrast is easy to
read even in direct sunlight. In dimly lit areas, press
the logo to turn on the backlight, page 21.
• Change your STP to match any standard
temperature and pressure reference, page 20.
• Log data to your PC with a serial data connection
to control the device and capture data for logging
and analysis, page 23.
This manual covers the following instruments:
• MC-Series: gas mass flow controllers
• MCW-Series: low pressure drop gas mass flow
controllers
• MCS-Series: anti-corrosive gas mass flow
controllers
• MCQ-Series: high-pressure gas mass
flow controllers
• MCE-Series: SEMI compatible
gas mass flow controllers
• MCV-Series: vacuum gas mass
flow controllers
• MCD-Series: dual-valve gas
mass flow controllers
For support or questions regarding
the use or operation of this device,
please contact us using the informa-
tion on page 2.
Alicat oers countless combinations of device sizes,
accessories, connections, and configurations. These
custom solutions are oered to meet a variety of
application challenges brought forth by users pushing
the boundaries of our standard oerings.
If you have an idea for a new process or a challenging
application, contact Alicat for specialized engineering
and application support.
MCRH5000SLPM
MCR100SLPM
MCP100SLPM

4 Table of Contents
Contents
Introduction 3
Quick Start Guide 5
Getting Started 6
Getting to Know Your Mass Flow Controller 6
The Flow Controller Display 6
Status Messages 6
Mounting 6
Filters 6
Device Ports 7
Connecting Your Gas Flow Controller 7
MCV Controller Operating Notes 8
MCD Dual Valve Controller Operating Notes 8
Power and Signal Connections 9
Analog Signals 9
Displaying Live Data 10
Option: Color TFT Display 11
Option: Collecting Totalized Flow Data 11
Dispensing Gas in Batches 12
Repeating a batch 12
Pausing or canceling a batch 12
Control 13
Changing the Setpoint 13
Adjusting Setpoint with an IPC 13
Setpoint Setup 13
Using Autotare 13
Changing Between Setpoint Sources 13
Managing Setpoint with an Idle Modbus Connection 13
Managing Setpoint on Power-Up 13
Establishing Setpoint Limits 14
Control Loop 14
Changing the Controlled Variable 14
Adjusting the PD/PDF or PDI Control Algorithms 14
Tuning the PDI Control Algorithm 15
Troubleshooting Valve Performance with PID Tuning 15
Limiting Flow Rate While Controlling Pressure 15
Using a Control Deadband for Pressure Control 16
Setpoint Ramping 16
Setting the Ramp Rate 16
Ramping Options 16
Displaying Valve Drive Percentage 17
Device Information 17
Setup 18
Gas Selection 18
Gas Select™ 18
Using COMPOSER™ Gas Mixes 18
Creating New Mixes in COMPOSER™ 19
Viewing, Deleting, and Creating Similar Mixes 19
Sensor Setup 20
Choosing Engineering Units 20
Defining STP/NTP Reference Values 20
Flow and Pressure Averaging 20
Zero Band 20
Configuring Serial Communications 21
Unit ID 21
Modbus RTU Configuration 21
Baud Rate 21
Display Setup 22
Main Screen Options 22
Screen Lighting 22
Display Rotation 22
Advanced Setup 22
Serial Communication 23
Modbus RTU Communication 23
Establishing Communication 23
Polling Mode 23
Streaming Mode 24
Taring 24
Collecting Data 24
Commanding a New Setpoint 25
Sending Setpoints as Floating Point Numbers 25
Using Gas Select™ and COMPOSER™ 25
Quick Command Guide 26
Troubleshooting 27
General Use 27
Flow Readings 27
Serial Communications 28
Maintenance 28
Cleaning 28
Recalibration 28
Reference Information 29
Engineering Units 29
Gas List by Number 30
Gas List by Category 31
Pinouts 32
8-Pin Mini-DIN (Default) 32
Locking Industrial Connector Pinout 32
9-Pin D-Sub Connector Common Pinouts 33
15-Pin D-Sub Connector Common Pinouts 33
M12 Connector Common Pinouts 34

2021.05.25  REV. 4  MASS FLOW CONTROLLER OPERATING MANUAL 5
Quick Start Guide
Setup
• Connect your flow controller. Ensure
that flow will pass through your device in
the same direction as the arrow on the
flow body (usually left to right).
• Choose your engineering units. You
can choose the measurement units by
selecting MAIN MENU →SETUP →Sensor
→ Engineering Units , see page 20
for more details.
Operation: Flow Verification
• Monitor live flow, temperature, and
pressure readings. Readings are
updated and displayed on your device
in real time. See page 6.
• (Optional) Capture totalized readings.
The totalizer option displays the total
flow that has passed through the device
since the last time the totalizer was reset.
If your device has a totalizer, press NEXT
from the main live data display to access
the totalizer. See page 11.
Connectors and Buttons
The drawing to the right represents a
typical configuration of a standard mass
flow controller. Your flow controller’s
appearance and connections may differ.
See page 2for more examples.
Backlight
The monochrome display comes equipped
with a backlight. To toggle the backlight
power, press the logo on the front of
your device.
For optional color TFT displays, pressing
this button will turn off the display to
conserve power. See page 11.
Maintenance and Care
• Flow controllers do not require cleaning
when flowing clean, dry gases. Read
more on page 28.
• Calibrate your flow controller annually.
To schedule a calibration, please contact
support (page 2).
+0.0 +0.0
+13.49 +22.73
Mass Flow
CCM SCCM MENU
PSIA ¤C SETPT
+0.0
SCCM
A ir
Process
Connection Mounting
Holes
Light
Switch
Softkey
Controls
LCD
Display
I/O PORT
DC
IN
This MC-1SLPM-D model mass
flow controller is a typical unit.
The flow body and the valve
sizes can vary significantly.

6 Getting Started
Getting Started
Getting to Know Your Mass Flow Controller
The Flow Controller Display
The figure to the right identifies the various features of the flow controller display.
Highlights pressure in the center of the device.
Highlights temperature in the center of the device
Opens a menu to set the flow or pressure control setpoint (page 13).
Highlights volumetric (actual) flow rate in the center of the device.
Highlights mass flow rate in the center of the device (default).
MENU enters the main menu system.
NEXT accesses the optional flow totalizer (page 11).
Toggles the backlight.
Status Messages
Status messages are shown to the right of the main readout number. In the example to the
right the OVR message indicates that the totalizer rolled over to zero.
ADC Analog-digital converter error
EXH Exhaust mode active
HLD Valve hold active
LCK Front display is locked
MOV Mass flow over range of device
OVR Totalizer rolled over to zero
POV Pressure over range of device
TMF Totalizer missed out-of-range flow
TOV Temperature over range of device
VOV Volumetric flow over range of device
Mounting
Flow controllers do not require straight runs of pipe upstream or downstream. Most flow
controller models can be mounted in any position, including upside-down. Corrosive-resistant
flow controllers use media-isolated sensors that must be tared after changing orientation.
▲Caution: Flow controllers with large Rolamite valves (see example to the right) should
be mounted with their valve oriented vertically (right-side up). For other orientations,
please contact support.
Filters
When pressure drop is not a concern, use in-line sintered filters to prevent large particulates
from entering the flow body of the controller. Suggested maximum particulate sizes are as
follows:
• 5 microns for units with flow ranges ≤1 .
• 20 microns for units with flow ranges between 1  and 1 .
• 50 microns for units with flow ranges ≥1 .
The Main Display. Note the button
behind the logo, which toggles the
device backlight.
The Main Display with barometer
(PSIG), valve % displayed (page 17),
an OVR status message, and a
totalizer (the NEXT button).
An MCR-50SLPM-TFT mass flow
controller, with its attached large
Rolamite valve.

2021.05.25  REV. 4  MASS FLOW CONTROLLER OPERATING MANUAL 7
Device Ports
Your controller has been shipped with plastic plugs fitted into its ports. To decrease the
chance of contaminating the flow stream, do not remove these plugs until you are ready to
install the device.
Standard gas flow controllers have female inlet and outlet ports. VCR®-compatible and other
specialty fittings may have male connections.
• If you are using a fitting that does not have a face seal, use thread-sealing Teflon tape to
prevent leakage around the port threads, but do not wrap the first two threads entering
the device. This will minimize the possibility of getting tape into the flow stream and
clogging the laminar flow elements.
• Face seal fittings do not need Teflon tape applied to the threads.
!
Warning: It is not recommended to use pipe dopes or sealants on the process connections
as these compounds can cause permanent damage to the controller should they get
into the flow stream.
Connecting Your Gas Flow Controller
Your flow controller can measure and control flow generated by positive pressure and/or
suction. Connect the controller so that the flow travels in the same direction as the flow
arrow, usually from left to right from the front of the device.
!
Warning: Using the flow controller above the maximum specified common mode, or
changing the pressure by more than the maximum recommended dierential pressure
too quickly, will result in permanent damage to the internal pressure sensors.
Model
Maximum
Common Mode Pressure
Maximum
Differential Pressure*
Standard controllers 175  75 
Low-pressure-drop controllers 80  10 
High-pressure controllers 400  75 
*The maximum dierential pressure only applies to the measurement portion of the device, and the valve
will act as a buer. The most common cause of this problem is giving the device a non-zero setpoint prior
to applying the pressure or suction to create flow. This will cause the valve to be fully open and expose
the sensor to any instantaneous changes in pressure, such as from a snap-acting solenoid valve.
Control Valve
(upstream valve shown)
Inlet
Connection Outlet
Connection
Flow Direction Indicator
A mass flow controller with male
VCR®-compatible connections.
A mass flow controller’s basic
process connections.
A mass flow controller with male
VCO®-compatible connections.

8 Getting Started
MCV Controller Operating Notes
Alicat’s MCV mass flow controller is equipped with an integrated
Swagelok® positive shuto valve. This valve is normally closed,
but can be opened by supplying 60–120  of air pressure.
The shut-o valve closes again when this pressure is reduced
below 60 .
A common method for actuating the shuto valve incorporates
a three-way solenoid valve (shown to the right). Pressure is
applied to one side of the solenoid valve while the other side
of the solenoid is left open to atmosphere. When the solenoid
is energized, pressure is delivered to the shuto valve, causing
it to open. When the solenoid is returned to a relaxed state, the
gas vents to atmosphere, allowing the shut-o valve to close.
MCD Dual Valve Controller Operating Notes
The MCD is a versatile dual-valve mass flow controller that
can be used to:
• Measure mass flow and volumetric flow in both directions,
plus absolute pressure and temperature.
• Control mass or volumetric flow from a pressurized source
or to vacuum.
• Control pressure in a flowing process.
• Control pressure in a closed volume with automatic venting.
An MCV-1SLPM-D mass flow controller.
An MCD-1SLPM-D
mass flow controller.
Outlet
Valve
Inlet
Valve
Process
Connection
Positive flow
Process
Gas
Source
Vacuum source or vent
Negative flow
+0.0 +0.0
+13.49 +22.73
Mass Flow
CCM SCCM MENU
PSIA ¤C SETPT
+0.0
SCCM
A ir
Three-way
solenoid valve
Vent
60―120
PSIG
MCV
Mass flow
controller
Pressure opens
the shuto valve
A typical MCV configuration.

2021.05.25  REV. 4  MASS FLOW CONTROLLER OPERATING MANUAL 9
Power and Signal Connections
Power can be supplied to your controller through either the power jack or the multi-pin
connector on top of your device.
✓ Note: Power requirements vary based on analog configuration and valve type. Please
reference the associated specification sheet at alicat.com/specs for power requirements.
Standard 8-Pin Mini-DIN Pinout
Pin Function
Not Connected Optional: 4–20 mA primary output signal
Static 5.12 Vdc by default. Optional: secondary analog output
(4–20 mA, 0–5 Vdc, 1–5 Vdc, 0–10 Vdc) or basic alarm
Serial RS-232 RX / RS-485(−) Input Signal (receive)
Analog Setpoint Input
Serial RS-232 TX / RS-485(+) Output Signal (send)
0–5 Vdc Optional: 1–5 Vdc or 0–10 Vdc output signal
Power In (as described above)
Ground (common for power, digital communications, analog signals and alarms)
The above pinout is applicable to all devices with the Mini-DIN connector. The availability of dierent output
signals depends on the options ordered. Optional configurations are noted on the unit’s calibration sheet.
▲Caution: Do not connect power to pins 1 through 6, as permanent damage can occur.
It is common to mistake pin 2 (labeled 5.12 Vdc Output) as the standard 0–5 Vdc analog
output signal. Pin 2 is normally a constant 5.12 Vdc.
For more pinout configurations, see page 32 to page 34.
Analog Signals
Primary Analog Output Signal
Most devices include a primary analog output signal, which is linear over its entire range.
For ranges that start at 0 Vdc, a zero-pressure condition is indicated at approximately 0.010
Vdc. Full scale pressure is indicated by the top of the range: 5 Vdc for 0–5 Vdc, 20 mA for
4–20 mA signals, and so on.
Option: Secondary Analog Output Signal
The default 8-pin Mini-DIN connector places the secondary analog output on pin 2 for
both voltage and current signals. Your device’s secondary analog signal may dier from its
primary output signal.
The calibration sheet that shipped with the device shows which output signals were ordered.
Option: 4–20 mA Current Output Signal
If your controller has a primary or secondary 4–20 mA current output signal, your flow
controller will require 15–30 Vdc power.
▲
Caution: Do not connect 4–20 mA devices to “loop powered” systems, as this will
damage portions of the circuitry beyond repair and void the warranty. If you must
interface with existing loop powered systems, always use a signal isolator and a separate
power supply.
MC-50SCCM-D mass flow
controller with the 8-pin Mini-DIN
connector on top.
Male Connector: Cable
Female Connector: Device
1
4
5
68
7
3
2 1
4
5
6
87
3
2

10 Getting Started
Displaying Live Data
Main Display
The main display has three primary functions:
• Displaying live temperature, pressure, and flow data
• Changing the flow or pressure control setpoint (page 13)
• Accessing the main menu (MENU) or the optional totalizer (NEXT) (page 11)
This screen displays live data for all flow parameters simultaneously. Live data is measured
1000 times per second and the LCD display is updated 10 times per second. The button
next to the four measurements highlight their values in the center.
Taring Your Flow Controller
MENU →TARE FLOW or TARES
Taring is an important practice that ensures your flow controller provides its most
accurate measurements. This function gives the flow controller a zero reference for flow
measurements. For controllers with a barometer, the absolute pressure reading can also
be tared when the device is exposed to the local barometric pressure.
How to Tare
When auto tare is on (Autotare: On), flow rate is tared whenever a zero setpoint is given for
more than two seconds. See (page 13).
Taring Flow
MENU →TARES →TARE FLOW
Flow tares should take place at the expected process pressure, with no flow. A message,
"ENSURE NO FLOW BEFORE PRESSING TARE" will be displayed. Press TARE to complete the
taring process.
Optional: Taring Pressure
MENU →TARES →TARE PRESS
Absolute pressure tares require an optional barometer, and the controller open to atmo-
sphere. A message, " PRESS TARE WHEN VENTED TO AMBIENT WITH NO FLOW " followed by " CURRENT
PRESSURE OFFSET:" will be displayed. The oset between the absolute pressure sensor in
the flow body and the internal barometer will also be displayed.
When to Tare
• Before every new flow measurement cycle
• After significant changes in temperature or pressure
• After dropping or bumping the flow controller
• After changing the device’s orientation The zero setpoint (autotare) menu
with autotare on (see page 13).
Tare mass flow by selecting
TARE FLOW from the main menu
(top), or TARES if the device has
a barometer (above).
The tare confirmation screen.
The main display.

2021.05.25  REV. 4  MASS FLOW CONTROLLER OPERATING MANUAL 11
Option: Color TFT Display
Instruments ordered with a color display are functionally the same as standard backlit
monochrome instruments. The color enables additional on-screen information.
Multi-Color Display Indicators
• GREEN: Parameter labels and adjustments associated with the button directly above or
below the label are presented in green.
• WHITE: The color of each parameter will be displayed in white when the device is
operating within device specifications.
• RED: The color of a parameter will be displayed in red when its value exceeds 128% of
the device’s specifications.
• YELLOW: Menu items that are ready to be selected appear in yellow. This color replaces
the >symbol in selections on monochrome display.
✓ Note: Press the logo to turn o the color display backlight. The flow controller remains
in operation while the backlight is o.
✓
Note: Color displays will require an additional 40 mA when using a 12 Vdc power supply.
All other device specifications from your device’s specification sheet remain in eect.
Option: Collecting Totalized Flow Data
MAIN DISPLAY →NEXT (totalizer menu)
The optional flow totalizer displays the total amount of mass or volume that has flowed
through the instrument since its last reset, similar to a gasoline pump. It also enables batch
dispensing (page 12).
• TOTAL/TIMER toggles between totalized flow and elapsed time as the highlighted
parameter in the center.
• SETPT displays the current setpoint. Press to set or clear a setpoint (page 13).
• SLPM (or another measurement of mass flow) displays the live flow rate. Press to change
engineering units.
• (Optional) M AVG or V AVG: Shows totalizer averaging, which displays average flow rate
since last reset, updated live.
• SL (in this example): Alternating display of selected engineering units for flow or time
(page 20) and the selected gas (page 18).
• BATCH selects the quantity to be dispensed in each batch. -NONE- appears if the batch
mode is o.
• RESET clears all totalized data and immediately resets the timer to . The next batch, if
set, begins immediately.
• MENU enters the main menu.
Totalizer Rollover Functions
The totalizer will report a maximum of 7 digits. By default, the placement of the decimal is
the same as the live flow rate. The totalizer can be configured at the time of order for the
following behaviors:
• Rollover (Default): Totalizer resumes counting from zero as soon as the maximum count
has been reached.
• Freeze: Totalizer stops counting at max count, until it is reset manually.
• Error (Default): Displays OVR status message when maximum count has been reached;
compatible with the rollover and freeze functions.
The elapsed time counter has a maximum value of 9999:59:59 (h:m:s) (416 days, 16 hours). If
flow is still being totalized at that point, the timer freezes, regardless of the behavior chosen
above for the totalized flow readings.
A typical TFT display.
The totalizer displaying a mass
flow average without a batch.

12 Getting Started
Dispensing Gas in Batches
Batch dispensing allows you to choose a desired total volume to flow, after which the valve
closes. You can repeat batches with a single button press.
Starting batch dispensing
1. From the totalizer screen, press BATCH. Choose the total quantity to be dispensed in
each batch. Press SET to accept the new batch size.
2. From the totalizer screen (page 11), press SETPT to choose a non-zero setpoint.
Flow begins as soon as you press SET.
✓ Note: Batch dispensing requires an active batch size and a non-zero setpoint. If your
controller already has a non-zero setpoint, flow begins as soon as you press SET from
the batch size screen.
While a new batch is being dispensed, the BATCH button changes to show the quantity that
remains to be dispensed. When the batch size has been achieved, the BATCH button displays
-DONE- and flow stops automatically.
The batch size can be changed while a batch is in progress. If the new batch size is larger
than the current totalized flow, then flow continues until the new value is reached. If the new
batch size is smaller than the current totalized flow, then the flow stops immediately. Press
RESET to start the new batch.
Repeating a batch
• For an identical, new batch, press RESET. Flow begins immediately.
• For a new batch of a dierent size, press BATCH, and select the new batch size. If there
is a non-zero setpoint, flow will begin as soon as SET is pressed.
Pausing or canceling a batch
1. To stop flow while a batch is in progress, set the mass flow setpoint to  by pressing
SETPT → CLEAR → SET within the totalizer menu. This will not stop the timer. Resume
flow with a non-zero set point.
2. To remove a batch setting, press BATCH or REMAIN → CLEAR → SET. Deleting the batch
does not aect the setpoint. Flow will continue at the setpoint rate.
! Warning: Flow will resume immediately at the current setpoint when batch dispensing
is turned o.
✓ Note: The batch size is retained across power cycles of your flow controller. It must be
manually cleared when no longer desired.
Using the Totalizer while Controlling Pressure
While using a mass flow controller to control pressure, the flow rate may exceed the maximum
measurable flow (128% of full scale) with an abrupt pressure change. In this case, the totalizer
will use the maximum 128% of full scale as the measured flow rate, the totalized flow value
will flash, and the TMF error will appear to indicate that the totalizer missed flow data. Reset
the totalizer to clear the error message.
Setting an upper flow limit (page 15) within the readable range will prevent this error;
however, this will take preference over reaching the pressure setpoint.
! Warning: In certain situations, it is possible to exceed the batch size. As an example, if
the feed pressure is too low to achieve the flow setpoint and then pressure is suddenly
increased, the batch size may be exceeded before the valve reacts to the sudden burst
of pressure.
Selecting a batch size of 1000 SL.
The totalizer displaying a mass
flow average without a batch, with
a batch in progress, and with a
finished batch.

2021.05.25  REV. 4  MASS FLOW CONTROLLER OPERATING MANUAL 13
Control
Changing the Setpoint
SETPT or MENU →CONTROL → Setpt:
The setpoint selection screen indicates the engineering units and maximum allowable
setpoint (e.g., SLPM: +10.000 Max). To cancel a setpoint, press CLEAR, then SET.
Adjusting Setpoint with an IPC
For controllers ordered with a potentiometer control knob (IPC), the setpoint source must be
set to analog for the controller to receive setpoint commands from the IPC (see “Changing
Between Setpoint Sources” below).
Leave the IPC knob at the midpoint when it is not in use.
Setpoint Setup
Using Autotare
CONTROL → Setpoint Setup → Zero Setpoint
When the setpoint is zero, the controller will automatically tare itself if autotare is enabled
(default). This menu also specifies how many seconds after given zero setpoint the controller
will wait before taring, under Delay Before Tare.
Setpoint ramping (page 16) can either be set to honor the ramp rate limit or go to zero
as quickly as possible.
Changing Between Setpoint Sources
CONTROL → Setpoint Setup → Setpoint Source
Mass flow controllers with RS-232 or RS-485 communication will accept setpoints from the
front panel and serial commands (see page 23), or from an analog signal.
• When the source is set to Serial/Front Panel, the controller will accept input from either
the front panel, or an RS-232/RS-485 connection. Neither source is a slave of the other,
so the controller will accept the most recent command from either source.
• When the source is set to Analog, the device ignores serial setpoint commands and will
prevent setpoint input from the front panel.
Managing Setpoint with an Idle Modbus Connection
CONTROL →Setpoint Setup → On Modbus Timeout
If a Modbus connection is timed out, the device can be configured to either set a zero
setpoint, or maintain the last setpoint it was given. The timeout time will be infinite by default
and can be adjusted (page 21).
Managing Setpoint on Power-Up
Power Up Setpoint Value
CONTROL →Setpoint Setup →Power Up Setpoint →Value
By default, the controller remembers its last setpoint across power cycles. However, it can
be changed to give a specified setpoint upon power up by selecting Fixed Setpoint and
entering a value. If the setpoint will be digitally provided more than every few minutes, use
a fixed setpoint on power-up to avoid wearing out non-volatile memory in the device.
Power Up Setpoint with Ramping
CONTROL →Setpoint Setup →Power Up Setpoint →Ramp
Any setpoint ramp will always start from zero on power-up. Similar to the zero setpoint
option (page 16), the device can either honor the ramp rate (Honor from 0) or jump to
setpoint (Jump from 0) as quickly as possible.
The control menu.
An IPC knob atop a controller.
The zero setpoint (autotare) menu
with Autotare off.
The setpoint source menu.
The modbus timeout menu.
The power-up setpoint menu.

14 Control
Establishing Setpoint Limits
CONTROL →Setpoint Setup → Setpoint Limits
The setpoint limits menu configures upper and lower limits for selecting a flow or pressure
control setpoint. By default, the controller will only be limited by its measuring range; however,
more strict limits may be beneficial in certain critical applications.
Over a serial connection, requesting a setpoint outside the limit will be rejected and an
error will be returned. When using an analog setpoint signal, setpoints that are outside of
the setpoint limits are treated as if they were at the nearest limit. For example, if you request
a setpoint that is below the lower limit, the controller sets the setpoint at the lower limit.
!
Warning: Flow controllers that have non-zero lower setpoint limits cannot be set to stop
flow until the lower limit has been cleared.
✓
Note: When changing from one control loop variable to another, the flow controller
remembers setpoint limits as percentages of full scale. For example, a 10- limit on
a 20- controller (50% of full scale) will become a limit of 80  (50% of 160 )
if the control loop is changed to absolute pressure.
Control Loop
Changing the Controlled Variable
CONTROL →Control Loop →Control
The controller can control the flow rate or the pressure in your process. Selectable control
loop variables include mass flow, volumetric flow, absolute pressure, and valve drive. Devices
with internal barometers also allow control of gauge pressure.
✓
Note: When pressure is selected as the control loop variable, flow controllers with
upstream valves will control the outlet pressure. Those with downstream valves can
control upstream back pressure, but these must be configured for this type of control.
! Warning: When changing the control loop from mass or volumetric flow to absolute or
gauge pressure, you may need to adjust the PID settings for optimal stability and speed
of response.
Adjusting the PD/PDF or PDI Control Algorithms
CONTROL →Control Loop →Loop Type
Your mass flow controller uses an electronic closed loop controller to determine how to
actuate its valve(s) in order to achieve the commanded setpoint. These settings were tuned
for your specific operating conditions, but changes to your process sometimes require on-site
adjustments to maintain optimal control performance. Fine-tuning your closed loop control
may help correct issues with control stability, oscillation, or speed of response.
For most applications, the PD/PDF algorithm is recommended. When controlling pressure
with an MCD dual valve controller, the PDI algorithm is recommended.
Tuning the PD/PDF control algorithm
The controller’s default control algorithm (PD) employs pseudo-derivative feedback (PDF)
control, which uses two editable variables:
• The larger the Dgain, the slower the controller will correct errors between the commanded
setpoint and the measured process value. This is equivalent to the Pvariable in common
PDF controllers.
• The larger the Pgain, the faster the controller will correct for osets based on the size of
the errors and the amount of time they have occurred. This is equivalent to the Ivariable
in common PDF controllers.
✓
Note: The D and P variables in the PD/PDF control algorithm are more typically referred
to as P and I, respectively, in PDF controllers.
Setting a minimum setpoint.
The setpoint limits menu.
The control loop menu in PD/PDF
control mode.
Setting a P Gain.

2021.05.25  REV. 4  MASS FLOW CONTROLLER OPERATING MANUAL 15
Tuning the PDI Control Algorithm
The controller’s PDI control algorithm (also called PDDI) is used to provide faster response,
most commonly in dual-valve flow and pressure controllers. This algorithm uses typical PI
terms and adds a squared derivative term (D):
• The larger the Pgain, the more aggressively the controller will correct errors between
the commanded setpoint and the measured process value.
• The larger the Igain, the faster the controller will correct for osets based on the size
of the errors and the amount of time they have occurred.
• The larger the Dgain, the faster the controller will predict needed future corrections
based on the current rate of change in the system. This often results in slowing the
system down to minimize overshoot and oscillations.
Troubleshooting Valve Performance with PID Tuning
The following issues can often be resolved by adjusting the PID gain values for your mass
flow controller.
Fast oscillation around the setpoint
• PD: Reduce the Pgain in decrements of 10%.
• PDI: Increase the Pgain in increments of 10%, and then adjust the Igain to fine-tune.
Overshot setpoint
• PD: Reduce the Pgain in decrements of 10%.
• PDI: If Dis not , increase the Pgain in increments of 10%.
Delayed or unattained setpoint
• PD: Increase the Pgain in increments of 10%, and then decrease the Dgain by small
amounts to fine-tune.
• PDI: Increase the Pgain in increments of 10%, and then increase the Igain to fine-tune.
✓ Valve tuning can be complex. More detailed information is available at alicat.com/pid.
Limiting Flow Rate While Controlling Pressure
CONTROL →Control Loop →Flow Limiter
Limiting the flow rate while controlling pressure can help to avoid exceeding the measurable
range of the device as well as prevent damage of sensitive devices later in the process.
To limit flow:
1. Choose either mass flow or volumetric flow to limit by pressing TYPE.
2. Set the maximum value of flow rate desired by pressing MAX FLOW and entering the
maximum value in the engineering units displayed.
3. Set the Limiter Gain to 500 and adjust as needed. Limiter gain determines how
aggressively the proportional control function will correct the error when the flow rate
exceeds the maximum flow setting. A higher value will correct more aggressively, but
is also more likely to oscillate near the flow limit.
✓
Note: If both flow limiting and pressure setpoint ramping are active when controlling
pressure, the more restrictive function will regulate the controller’s operation as it
attempts to attain the setpoint.
✓
Note: For bidirectional controllers, the flow limit will be symmetric. For example an
MCD-20SLPM with a maximum set to 10 SLPM will be limited to between −10 slpm and
10 slpm.
The control loop menu in PD²I
control mode.
The flow limiter menu.
Setting a maximum flow limit.

16 Control
Using a Control Deadband for Pressure Control
CONTROL →Control Loop →Control Deadband
The control deadband is designed to minimize the amount of gas exhausted and improve
stability. There is no active control within the deadband setting.
✓Note: A control deadband cannot be set when the device is configured to control flow
(the Control menu item within the control loop menu, see page 14). If control is set to
mass flow, the error, Only active when controlling pressure will show instead
of the deadband menu.
To turn on the control deadband, enter a non-zero value in CONTROL → Control Deadband →
Deadband. The controller must first reach the setpoint for the deadband to activate. If the
process variable drifts outside a deadband limit, active control resumes until the setpoint
is reached again.
The controller can be set to either hold the current valve position or close the valve(s) in
CONTROL → Control Loop → Control Deadband → When in Band. It is recommended to hold
the current position on MC-Series devices and close valves for MCD-Series devices.
Example: With a setpoint of 30 , a deadband of ±0.25  allows absolute pressure
to vary between 29.75 and 30.25 . The device will hold the current valve position until
the pressure reading varies outside of the preset deadband.
▲
Caution: MC-Series devices do not have an exhaust valve to reduce pressure when
pressure exceeds the deadband.
Setpoint Ramping
Setpoint ramping regulates how quickly the controller will reach the flow or pressure setpoint.
It is often used to prevent bursts of pressure or flow from damaging delicate instruments
when starting a process.
To activate setpoint ramping, you will set a maximum ramp rate and configure when to
enable the ramping function.
Setting the Ramp Rate
• Ramp is a quick way to change the maximum rate of change.
• Units is a quick way to change the engineering units used.
• Set By Delta / Time allows for more detailed control of the ramp rate including changing
the value of the time period.
Ramping Options
Changing ramping options allows you to have a ramp in only one direction, increasing
or decreasing. It also allows you to ignore the ramp rate when initially powering on or
commanding a zero setpoint.
• Ramp Up can toggle between on and o. When o, the ramp rate will not be honored
when increasing flow to reach a given setpoint.
• Ramp Down can toggle between on and o. When o, the ramp rate will not be honored
when decreasing flow to reach a given setpoint.
• Power Up toggles between Allow Ramp and No Ramp . If set to No Ramp , the device will
ignore the ramp rate just after powering on, otherwise it will honor the ramp rate from
a zero setpoint.
• 0 Setpt determines whether the controller ramps when a zero setpoint has been given.
If this setting is set to No Ramp, when given a zero setpoint, the controller will immediately
snap to the zero setpoint; otherwise it will ramp at the selected rate.
✓ Note: Setpoint ramping can be used with flow or pressure setpoints, depending on the
control loop selected. Ramping for pressure control limits how quickly pressure changes
before reaching the setpoint. To limit flow rates directly while controlling pressure, see
page 15.
The deadband menu.
Choosing deadband options.
Choosing deadband size.
The setpoint ramping menu.
Setting a maximum ramp rate.
Configuring delta/time ramping.

2021.05.25  REV. 4  MASS FLOW CONTROLLER OPERATING MANUAL 17
Displaying Valve Drive Percentage
The valve drive is represented as a percentage of the amount of voltage driven to the valve.
Percentages do not directly correlate with percentage open.
Viewing the valve drive percentage is particularly helpful for troubleshooting. An increase
in percentage over time likely indicates a clog in the system where more voltage is required
to drive the valve to attain the same amount of flow. A valve percentage of 0% indicates
the valve is not open.
This information may be displayed on the main display and/or as part of transmitted serial
data. There are four valve display options:
• None: No valve information is displayed.
• Main Screen: Only on the main display.
• Digital Data: Only in the serial data frame.
• Screen and Digital: Both the main display and serial data frame.
Device Information
The ABOUT menu (MENU →ABOUT) contains useful information for setup, configuration, and
troubleshooting.
Basic Device Information
ABOUT →About Device
This includes information on the following:
• MODEL: Device model
• SERIAL NO: Serial number
• DATE MFG: Manufacturing date
• DATE CAL: Most-recent calibration date
• CAL BY: Initials of the person who calibrated the device
• SW: Firmware version
• Display SW (color displays only): Firmware version of the display
Device Full Scale Ranges
ABOUT →Full Scale Ranges
This displays the maximum calibrated range of available flow and pressure readings. Most
will include mass flow, volumetric flow, and absolute pressure. Devices equipped with an
optional barometer will also show gauge and barometric pressures.
Manufacturer Information
ABOUT →About Manufacturer
About Manufacturer usually includes:
• Manufacturer name
• Web address
• Phone number
• Email address
The valve display menu
Valve percentage on the main
display, above the large numbers.
The about device screen.
The full scale ranges screen.
The about menu.

18 Setup
Setup
Gas Selection
MENU →SETUP →Active Gas
Gas Select™
In most cases, your flow controller was physically calibrated at the factory using air. Gas
Select™ allows you to reconfigure the flow controller to flow a dierent gas without any
need to send it back for a physical recalibration.
Within this menu, there are a variety of categories (such as Standard, Chromatography and
Welding ), as well as recent selections, and ™ mixes (see next page). Each category
will list a subset of available gases and preconfigured mixtures.
As soon as you press SET from the gas list, your flow controller will reconfigure its flow rate
calculations to the newly selected gas’s properties. There is no need to restart the device.
Your current gas selection appears just below the unit’s indicator on the right side of the
main display (see page 10).
Category and Gas List Controls
• PAGE advances the view to the next page of categories or gases.
• SELECT (in the category list) opens a list of gases in that category.
• SET (in the gas list) immediately loads the gas measurement properties and exits to the
setup menu.
Using COMPOSER™ Gas Mixes
SETUP →Active Gas →COMPOSER Mixes
To remain accurate, your flow controller needs to reference the viscosity of the gas you are
flowing through it. The more closely you can define your actual gas composition, the more
accurate your flow readings will be. ™ is an included feature of Gas Select™ that
lets you define new mixed gas compositions to reconfigure your flow controller on the fly.
Wilke’s semi-empirical method is used to define a new gas mixture based on the molar
(volumetric) ratios of the gases in the mixture. You can define these gas compositions to
within 0.01% for each of up to five constituent gases in the mixture. Once you define and
save a new ™ gas mix, it becomes part of the Gas Select™ system and is accessible
under the gas category COMPOSER User Mixes . You can store up to 20 ™ gas mixes
on your flow controller simultaneously.
✓
Note: The ™ is device firmware, and does not physically mix gases. It only
configures the device’s calculations to report flow readings more accurately based on
the constituent gases of your defined mixture.
Select any existing mix and press SET to immediately configure your device to measure that
gas mixture. To create new mixes, see the next section.
The first page of the Gas Select™
category list.
The setup menu.
The Gas Select™ standard gas list.

2021.05.25  REV. 4  MASS FLOW CONTROLLER OPERATING MANUAL 19
Creating New Mixes in COMPOSER™
SETUP →Active Gas →COMPOSER Mixes →Create Mix
Give the Mix a Short and Long Name
UP/DOWN will change the character. Valid characters include A–Z, 0–9, punctuation (. , -),
and space. CANCEL exits to the mix settings menu. SET accepts the name.
✓
Note: Using a space in the short name can cause the serial data frame to be read
incorrectly by some programs.
Define the Mix.
• Add Gas to Mix enters the Gas Select™ category listing. Once you find the correct gas,
press SET. Enter the composition percentage and press SET.
• As gases are added, the total used percentage will be shown on the mix settings menu.
• Once gases have been added, ™ can change the gas percentage to fill the
remaining portion to 100% by selecting the component gas, then selecting Set % to
Balance.
• The mixture can be saved when its gases total 100% by selecting Save Mix. Selecting
BACK will permanently discard the mix.
• Mixes that contain several gases will push the menu to a second page; use the PAGE
button to see the remaining list.
Viewing, Deleting, and Creating Similar Mixes
SETUP →Active Gas →COMPOSER Mixes →[Select mix] →INFO
The current configuration of any existing ™ mix can be viewed by selecting INFO
instead of SET in the mix list. It will show:
• Options to delete the mix, or to create a similar mix.
• Short and long names.
• The gas number.
• The composition, which may extend to a second page; if so, pressing the PAGE button
will move to the next page.
The mix settings menu.
Defining a mixture’s long name.
The ™ menu with the
new custom mix.
Setting the percentage of a
constituent gas CH
The results of the addition of CH
The COMPOSER™ menu without
existing mixes.

20 Setup
Sensor Setup
MENU →SETUP →Sensor
Choosing Engineering Units
SETUP →Sensor →Engineering Units
Changing engineering units alters both the display and the data frame. Choose the parameter
whose unit you want to change, and then choose an engineering unit, confirming the change
on the last screen.
Defining STP/NTP Reference Values
SETUP →Sensor →STP Flow Ref or NTP Flow Ref
Standardized flow rates are reported in “standard” or “normal” volumetric flow units that
reference a given temperature and pressure combination. This reference is called STP
(standard temperature and pressure) or NTP (normal temperature and pressure). Depending
on the engineering units selected, either STP or NTP will be editable from this menu.
Reference options:
• Stan T: Standard Temperature
• Stan P: Standard Pressure
• Norm T: Normal Temperature
• Norm P: Normal Pressure
• Ref temp units changes the temperature units used for STP and NTP calculations.
• Ref pressure units changes the pressure units used for STP and NTP calculations
Unless otherwise requested, your flow controller ships with a default STP of 25°C and 1 atm
(which aects flow units beginning with “S”), and an NTP of 0°C and 1 atm (which aects
flow units beginning with “N”).
!
Warning: Changes to STP or NTP references will alter your mass flow readings.
Flow and Pressure Averaging
SETUP →Sensor →Flow Averaging
SETUP →Sensor →Pressure Averaging
Averaging the flow over a longer time may be useful in smoothing fluctuating readings. This
menu changes the time constants of the geometric running averages for flow and pressure.
Values roughly correspond to the time constant (in milliseconds) of the averaged values.
Higher numbers generate a greater smoothing eect, to a maximum of 255 ms.
Zero Band
SETUP →Sensor →Zero Band
The zero band threshold is an amount of flow under which flow values are displayed as .
The maximum zero band is 6.38%. This function also applies to gauge pressure readings
when using the optional barometer. For example, a 20  controller with a zero band
value of 0.25% would display as   for all readings below 0.05 .
The sensor setup menu.
The engineering units menu,
including units for the totalizer
(page 11).
Adjusting the flow averaging time
constant.
Configuring the zero band.