Halma ALICAT SCIENTIFIC PC Series User manual

OPERATING MANUAL
FOR PRESSURE CONTROLLERS
Models PC · PCS · PC3 · IVC

2 Introduction
Thank you for purchasing your pressure 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 pressure controller every year.
Annual calibration is necessary to ensure the continued accuracy
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, visit alicat.com/certifications for more information.
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-PC Rev 1 • 2021.05.26
PCR5PSID
PCR5PSIG

2021.05.26  REV.   PRESSURE CONTROLLER OPERATING MANUAL 3
Introduction
Your pressure controller has many innovative features:
• 1000 readings per second guarantees high
resolution data, page 11.
• 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 19.
• Ability to control gases and liquids to accommodate
a wide range of pressure control applications.
• Connection to a computer for control and data
logging to capture all pressure data for logging
and analysis, page 20.
This manual covers the following instruments:
• PC-Series: absolute, gauge, and differential
pressure controllers
• PCS-Series: anti-corrosive absolute, gauge, and
dierential pressure controllers
• PC3-Series: remote-sensing pressure controllers
• IVC-Series: integrated vacuum controllers
• EXTSEN-Series: external sensor pressure
controllers
For support or questions regarding the use or oper-
ation of this device, please contact us using the
information on page 2.
Alicat oers countless combinations of device sizes,
accessories, connections, and configurations. These
custom solutions are offered 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.
PCP5PSID
PC1PSIG
PCP5PSIG

4 Table of Contents
Contents
Introduction 3
Quick Start Guide 5
Getting Started 6
Getting to Know Your Pressure Controller 6
The Pressure Controller Display 6
Status Messages 6
Mounting 6
Filters 6
Device Ports 7
Connecting Your Pressure Controller 7
Forward (Downstream) Pressure Control 8
Back Pressure Control 8
Dierential Pressure Control 8
Remote-Sensing Controller 9
Integrated Vacuum Controllers (IVC) 9
Using Alicat Pressure Instruments with Liquids 9
Power and Signal Connections 10
Analog Signals 10
Displaying Live Data 11
Main Display 11
Taring Your Pressure Controller 11
Option: Color TFT Display 11
Control 12
Changing the Setpoint 12
Adjusting Setpoint with an IPC 12
Setpoint Setup 12
Using Autotare 12
Changing Between Setpoint Sources 12
Managing Setpoint with an Idle Modbus Connection 12
Managing Setpoint on Power-Up 12
Establishing Setpoint Limits 13
Control Loop 13
Changing the Controlled Variable 13
Adjusting the PD/PDF or PD²I Control Algorithms 13
Tuning the PD²I Control Algorithm 14
Troubleshooting Valve Performance with PID Tuning 14
Using a Control Deadband for Pressure Control 14
Setpoint Ramping 15
Setting the Ramp Rate 15
Ramping Options 15
Displaying Valve Drive Percentage 15
Device Information 16
Setup 17
Sensor Setup 17
Choosing Engineering Units 17
Pressure Averaging 17
Zero Band 17
Configuring Serial Communications 18
Unit ID 18
Modbus RTU Configuration 18
Baud Rate 18
Display Setup 19
Main Screen Options 19
Screen Lighting 19
Display Rotation 19
Advanced Setup 19
Serial Communication 20
Modbus RTU Communication 20
Establishing Communication 20
Polling Mode 20
Streaming Mode 21
Taring 21
Collecting Data 21
Commanding a New Setpoint 22
Sending Setpoints as Floating Point Numbers 22
Quick Command Guide 22
Troubleshooting 23
General Use 23
Pressure Readings 23
Serial Communications 24
Maintenance 24
Cleaning 24
Recalibration 24
Reference Information 25
Engineering Units 25
Pinouts 26
8-Pin Mini-DIN (Default) 26
Locking Industrial Connector Pinout 26
9-Pin D-Sub Connector Pinouts 27
15-Pin D-Sub Connector Pinouts 27
M12 Connector Pinouts 28

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Quick Start Guide
Setup
• Connect your pressure 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 17 for more details.
Operation: Pressure Verification
Monitor live pressure readings. Readings are
updated and displayed on your device in real
time. See page 11.
Connectors and Buttons
The drawing to the right represents a typical
configuration of a standard pressure controller.
Your pressure controller’s appearance and
connections may differ. See page 2 for
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 o the display to conserve power.
See page 11.
Maintenance and Care
• Pressure controllers do not require cleaning
when flowing clean, dry gases. Read more
on page 24.
• Calibrate your device annually. To schedule
a calibration, please contact support
(page 2).
This PC-1PSIG-D is a
typically-configured
pressure controller.
This is a typical gauge
pressure configuration.
This is a typical differential
pressure configuration.

6 Getting Started
Getting Started
Getting to Know Your Pressure Controller
The Pressure Controller Display
The figure below identifies the various features of the main pressure controller display.
Highlights pressure in the center of the display.
Tares the pressure (typically unavailable for abso-
lute pressure devices) (page 11).
Opens a menu to set the pressure control setpoint (page 12).
Enters the main menu system (page 11).
Toggles the backlight (more display options are on page 19).
✓ Note: Buttons 4 and 5 have no functions on the main display for pressure devices.
Status Messages
Status messages are shown to the right of the main readout number. In the example to
the right the LCK message indicates that the front display is locked.
ADC Analog-digital converter error
LCK Front display is locked
POV Pressure over range of device
Mounting
Pressure controllers do not require straight runs of pipe upstream or downstream. Most
pressure controllers can be mounted in any position, including upside-down. Corrosive-re-
sistant pressure controllers use media-isolated sensors that must be tared after changing
their orientation.
▲
Caution: Pressure controllers that use large Rolamite valves (PCR, PCR3, PCRS) should
be mounted with their valve oriented vertically (right-side up). Please contact Alicat
for other orientations.
Filters
When pressure drop is not a concern, use in-line sintered filters to prevent large particulates
from entering the pressure controller. Suggested maximum particulate sizes are as follows:
• 20 microns for PC, PCP, PCH, PC3
• 40 microns for PCR, PCR3 A PCR-5PSID-D pressure controller,
with its large Rolamite valve.
The main display. Note the button
behind the logo, which toggles the
device backlight.
The main menu with valve position
information, and a LCK status.

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Device Ports
Your pressure 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 pressure controllers have female inlet and outlet ports. VCR® 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. This
will minimize the possibility of getting tape into the flow stream.
• 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 Pressure Controller
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 pressure controller above the maximum specified common mode
or burst pressure will result in permanent damage to the internal pressure sensors.
Range Burst Pressure
Maximum Allowed Common Mode
Pressure (Differential Pressure Only)
0.07-100 PSI 3x full scale 200  (750  for anti-corrosive models)
500 PSI 1.5x full scale 750 
1000-3000 PSI 1.5x full scale N/A
A male VCR®-compatible
connection.
A default NPT female connection.
A male VCO®-compatible
connection.

8 Getting Started
Applications
Forward (Downstream) Pressure Control
When the valve is located on the upstream side (direct control), the sensor will control
pressure downstream. This configuration follows our standard pressure control algorithm.
Note: the valve opens to increase pressure, and closes to decrease pressure.
Example:
Gas Supply Pressure Regulator Pressure Controller Process Flow Exit Port
Upstream Valve
Back Pressure Control
When the valve is located on the downstream side (inverse control), the sensor will control
pressure upstream. This configuration is referred to as a back pressure controller. This
configuration follows our inverse pressure control algorithm. Note: the valve closes to
increase pressure, and opens to decrease pressure.
Example:
Gas Supply Pressure Regulator Pressure ControllerProcess Flow Exit Port
Downstream Valve
✓
Note: Back pressure controllers include “DS,” for downstream valve, in their part codes.
Changing the Valve Orientation
The valve position on your pressure controller can be switched in the field. The controller
must also be configured for either forward pressure control (direct control) or back pressure
control (inverse control). If you need to switch from forward to back pressure control, a video
and explanation can be found at alicat.com/valve-direction-change.
Dierential Pressure Control
Dierential pressure controllers have two ports for connecting to the points in the system
where the dierential pressure is to be measured. The upstream port is for the higher
pressure, and the downstream port is for the lower pressure. In these devices, the dierential
pressure ports have no flow, and are not connected to the flow path.
A 15-PSID pressure controller with
two differential pressure detector
ports in front and a DB-9 serial
connector.

2021.05.26  REV.   PRESSURE CONTROLLER OPERATING MANUAL 9
Remote-Sensing Controller
PC3-Series models sense and control the pressure at some point in the system outside of
the pressure controller itself. All PC-Series controllers can be ordered with an additional
NPT port on the front, which is connected directly to the pressure sensor in the device. The
pressure sensor is isolated from the flow path in this configuration.
Integrated Vacuum Controllers (IVC)
IVCs are similar to the PC-Series absolute pressure controllers in functionality and in the
navigation menus available on the screen. IVC devices are used in applications where
precise control of vacuum is required, and are available with 10 TorrA, 100 TorrA, 1000 TorrA,
and combined 1000 & 10 Torr sensors.
Integration of the vacuum sensor, control valve, and PID algorithm in a single device eliminates
the need for an external vacuum sensor and throttle valve in your system. These devices
have /-20 SAE ports, or optional VCR®-compatible, compression, and VCO®-compatible
fittings. Process port sizes may change depending on the valve on your device.
Using Alicat Pressure Instruments with Liquids
Many pressure devices may be used with chemically-compatible liquids, but a few warnings
must be taken into account:
• Water is more than 55 times more viscous than air. This is important when sizing a pressure
controller, as this significant increase in viscosity requires a larger valve to reach expected
flow rates. For example, a PC-Series pressure controller sized to flow up to 20  of
air will be limited to roughly 0.5 LPM of water (or similar fluid).
• The factory PID tuning is done using air. It may be necessary to adjust the PID tuning
parameters when using a controller with liquid. Find more information at alicat.com/PID,
or contact us (page 2) to help you through this tuning process.
▲
Caution: Please check with Alicat before using your pressure controller with liquids
unless specifically ordered for this purpose.
A PC3-Series 100-PSIG pressure
controller with its remote sensing
port in front, and a Mini-DIN serial
connector.
Gas
Supply
Alicat PC3
Controller
Flow
Pressure Sensor Line (no flow)
Process
An IVC-Series absolute (vacuum)
pressure controller.
Gas Supply
Alicat IVC
Optional Remote Sensor (on IVC3 models)
Process
Exhaust
Vacuum Pump

10 Getting Started
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 (5.12 Vdc Output) as the standard 0–5 Vdc analog output
signal. Pin 2 is normally a constant 5.12 Vdc.
More pinout configuration options begin on page 26.
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. As pressure is the only measured parameter in the pressure
series, this secondary analog output can be used as a comparison to the primary analog
output.
Option: 4–20 mA Current Output Signal
Controllers with a primary or secondary output signal of 4–20 mA current 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.
A 500-PSIG pressure controller
with the standard 8-pin Mini-DIN
serial connector.
Male Connector: Cable
Female Connector: Device
1
4
5
68
7
3
2 1
4
5
6
87
3
2

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Displaying Live Data
Main Display
The main display has four primary functions:
• Displaying live pressure data
• Setting the pressure controller’s setpoint
• Taring the pressure (page 11)
• Accessing the main menu (MENU)
Live data is measured 1000 times per second, and the LCD display is updated 10 times per
second. The button next to the measurement highlights its value in the center.
Taring Your Pressure Controller
MENU →TARE PRESS or TARES
Taring ensures your pressure controller ensures its most accurate measurements. This
function gives the pressure controller a zero reference for pressure measurements.
How to Tare
MENU →TARES →TARE PRESS
• Tares should be performed with the pressure controller open to atmosphere with no flow.
• Absolute pressure devices can be tared if purchased with the optional internal barometer,
and then opened to atmosphere with no flow.
• Dierential pressure devices require zero dierential pressure between the P1 and P2
ports. They must be either open to atmosphere on both ports, or connected to the same
pressure source.
When to Tare
• Before every new pressure measurement cycle
• After significant changes in temperature or pressure
• After dropping or bumping the pressure controller
• After installing the controller in a dierent orientation
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 pressure 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.
The main display. Note the button
behind the logo, which toggles the
device backlight.
The zero setpoint (autotare) menu
with Autotare on (page 13).
Tare pressure by selecting TARE
PRESS from the main menu.
A PCD3-1000PSIG-TFT-PCA13
model device with a TFT screen.

12 Control
Control
Changing the Setpoint
SETPT or MENU →CONTROL → Setpt:
The setpoint selection screen indicates the engineering units and maximum allowable
setpoint (e.g., PSIG: +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.
This menu also specifies how many seconds after a zero setpoint the controller will wait,
under Delay Before Tare.
▲Caution: Auto-tare is typically not recommended for pressure control applications.
Setpoint ramping (page 15) 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
Pressure controllers with RS-232 or RS-485 communication will accept setpoints from the
front panel and serial commands (page 20), 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 idle for a specified amount of time, the device can be configured
to set a zero setpoint, or maintain the previous setpoint. The idle time will be infinite by
default and can be adjusted (page 18).
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 in a value. If the setpoint will be digitally provided more often than every few
minutes, use a fixed setpoint on power-up to avoid wearing out the device’s non-volatile
memory.
The control menu.
An IPC knob atop a controller.
The zero setpoint (autotare) menu
with autotare on.
The setpoint source menu.
The modbus idle time menu.
The power-up setpoint menu.

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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 12), the device can either honor the ramp rate (Honor from 0) or jump to setpoint
(Jump from 0) as quickly as possible.
Establishing Setpoint Limits
CONTROL →Setpoint Setup → Setpoint Limits
The setpoint limits menu configures upper and lower limits for selecting a 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.
✓
Note: When changing from one control loop variable to another, the pressure controller
remembers setpoint limits as percentages of full scale. For example, a 15- limit on
a 30-PSIG pressure controller (50% of full scale) will become a limit of 50% if the control
loop is changed to valve drive.
Control Loop
Changing the Controlled Variable
CONTROL →Control Loop →Control
Selectable control loop variables include pressure (absolute, gauge, or dierential) and
valve drive.
✓ Note: Pressure controllers with upstream valves will control the outlet pressure. Those
with downstream valves can control upstream backpressure, but these must be
configured for this type of control.
! Warning: When changing the control loop, 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 pressure 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 issues with control stability, oscillation, or speed of response.
For most applications, the PD/PDF 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.

14 Control
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 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 pressure
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.
✓
Note: Valve tuning can be complex. More detailed information is available at
alicat.com/pid.
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.
To turn on the control deadband, enter a non-zero value in CONTROL → Control Deadband
→ Deadband. In order for the deadband to activate, the controller must reach the setpoint.
If the process variable drifts to 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 PC-Series controllers.
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 increase pressure until it reaches
the setpoint of 30 . With a setting of Hold valve position, it will hold the current valve
position until the pressure reading varies outside of the preset deadband.
▲
Caution: PC-Series devices do not have an exhaust valve to reduce pressure when
pressure exceeds the deadband. A dual-valve (PCD-Series) pressure controller with an
exhaust valve is recommended for closed volumes.
The control loop menu in PD²I
control mode.
The deadband menu.
Choosing deadband options.
Choosing deadband size.

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Setpoint Ramping
Setpoint ramping regulates how quickly the controller will reach the pressure setpoint. It
is often used to prevent bursts of 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 pressure to reach a given setpoint.
• Ramp Down can toggle between on and o. When o, the ramp rate will not be honored
when decreasing pressure 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.
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 increased
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 closed.
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.
The setpoint ramping menu.
Setting a maximum ramp rate.
Configuring delta/time ramping.
The valve display menu
Valve percentage on the main
display, above the large numbers.

16 Device Information
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 pressure readings. Most will
include only one type of pressure. Devices equipped with an optional barometer will show
absolute, gauge, and barometric pressures.
Manufacturer Information
ABOUT →About Manufacturer
About Manufacturer usually includes:
• Manufacturer name
• Web address
• Phone number
• Email address
The about device screen.
The full scale ranges screen.
The about menu.

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Setup
Sensor Setup
MENU →SETUP →Sensor
Choosing Engineering Units
SETUP →Sensor →Engineering Units
Changing device engineering units alters both the display and the data frame. Choose the
parameter whose unit you want to change, and then select your desired engineering unit,
confirming the change on the last screen.
Pressure Averaging
SETUP →Sensor →Pressure Averaging
Averaging the pressure over a longer time may be useful in smoothing fluctuating readings.
This menu changes the time constant of the geometric running average for 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 pressure under which pressure values are displayed
as 0. The maximum zero band is 6.38%. For example, a 20  setting with a zero band
value of 0.25% would display as 0  for all readings below 0.05 .
Selecting engineering units.
Selecting a pressure average.
Selecting a zero band.
The sensor setup menu.
The setup menu.

18 Setup
Configuring Serial Communications
MENU →SETUP →RS-232 Serial or RS-485 Serial
You can operate the pressure controller remotely via its data connection for easy streaming
and logging of all data. Before connecting the pressure controller to a computer, ensure
that it is ready to communicate with your computer by checking the options in this menu.
For more on how to issue commands from a computer, see page 20.
Unit ID
SETUP →RS-232 Serial or RS-485 Serial →Unit ID
The unit ID is the identifier that a computer uses to distinguish your device from other, similar
devices when connected to a network. Using the unit ID letters A–Z, you can connect up
to 26 devices to a computer at the same time via a single  port. This is called polling
mode (page 20). Unit ID changes take eect when you select SET.
If you select “@” as the Unit ID, the pressure controller will enter streaming mode when
you exit the menu (page 21).
Modbus RTU Configuration
SETUP →RS-232 Serial or RS-485 Serial →Modbus Address
SETUP →RS-232 Serial or RS-485 Serial →Modbus
Modbus Address
The Modbus address is the identifier that a computer or programmable logic computer (PLC)
uses to distinguish your device from other devices when connected to a Modbus network.
Values of 1–247 are available for use.
Managing Setpoint with an Idle Modbus Connection
If a Modbus connection is idle for a specified amount of time, the device can be configured
to set a zero setpoint, or maintain the previous setpoint. The idle time will be infinite by
default and can be set in seconds up to 99999.9 seconds (1 day, 3 hours, 46 minutes, 39.9
seconds).
Baud Rate
SETUP →RS-232 Serial or RS-485 Serial →Baud Rate
Baud rate is the speed at which digital devices transfer information. The pressure controller
has a default baud rate of 19200 baud (bits per second). If your computer or software uses
a dierent baud rate, you must change the pressure controller’s baud rate in the BAUD menu
to ensure they match. Alternatively, you can change your computer’s baud rate in Windows®
Device Manager. Baud rate changes take eect once you press SET, but you may need to
restart the software for it to recognize the change.
The serial communication menu.
Choosing a unit ID, or streaming.
Baud rate options.
The Modbus address menu.
The Modbus idle menu.
Setting a Modbus idle disconnect
time.

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Display Setup
MENU →SETUP →Display
The options in the display setup menu adjust the contrast/brightness of the display and
enable screen rotation.
Main Screen Options
SETUP →Display →MAIN Screen
• Any Key Press changes what happens when any of the parameter buttons on the main
display (page 11) are pressed (pressure or temperature, for example). By default,
these buttons highlight their measurement in the center of the display. If this option is
set to Show Actions Menu, an option to change that parameter’s engineering units will
be shown, as well as an option to highlight the parameter.
• Show Valve Drive shows or hides the valve’s drive percentage. See page 15.
• Top Left Key Value and Bot Left Key Value will show if the device has an optional
barometer installed. This option configures which type of pressure (barometric, gauge,
absolute) is displayed.
Screen Lighting
SETUP →Display →Screen Lighting
The options and wording in the screen lighting menu will vary for monochrome versus
color displays.
• On monochrome displays, press LESS CONTRAST or MORE CONTRAST to adjust the contrast
levels and move the contrast indicator left or right. POWER UP Lit or Dark toggles whether
the backlight of the unit will be on when the device powers on.
• On color displays, press DIMMER or BRIGHTER to adjust the brightness level and move the
brightness indicator left or right.
Display Rotation
SETUP →Display →Display Rotation
The device has the option of inverting (flipping) the screen upside-down, as configured in
this menu.
Advanced Setup
MENU →SETUP →Advanced
The advanced setup menu contains settings and detailed information that are useful when
troubleshooting with customer support.
Factory Restore
SETUP →Advanced →Factory Restore
This will immediately take you to a confirmation screen. When troubleshooting, an appli-
cations engineer may recommend doing a Factory Restore. If something is not acting as
expected, please contact an applications engineer prior to doing a Factory Restore.
Register Status
SETUP →Advanced →Register Status
The Register Status screen displays live values for the internal device registers. Many of
these values can help an applications engineer diagnose operational issues over the phone.
Some register values clearly distinguish between hardware and operational problems, which
speeds up the troubleshooting process.
Edit Register and Device Properties
SETUP →Advanced →Edit Register
SETUP →Advanced →Device Properties
!
Warning: Editing these settings may cause the device to become inoperable. Do not
modify them without working with an applications engineer.
The advanced setup menu.
The register status list.
The display setup menu.
The options for pressing buttons
on the main display.
The monochrome contrast menu.

20 Serial Communication
Serial Communication
Connecting your device to a computer allows you to log the data that it generates. The pressure controller communicates
digitally through its communications connector and cable using a real or virtual  port on your computer. This section
of the manual shows you how to operate the pressure controller using ASCII commands.
Modbus RTU Communication
For details on Modbus commands, please visit alicat.com/manuals for the Modbus operating bulletin.
Establishing Communication
After connecting your pressure controller using a communications cable, you will need to establish serial communications
through a real or virtual  port on your computer or programmable logic computer (PLC).
• If the device is connected to a serial port, note its  port number. This can be found in Windows® Device Manager.
• If you have used a USB cable to connect your device to your computer, then in most cases it will recognize your USB
as a virtual  port. If it does not, download the appropriateUSB device driver at alicat.com/drivers and note the
 port number as found inWindows® Device Manager.
The controller will be configured with the following settings:
• Baud: 19200 (by default; others can be used if the computer, its software and the controller are all set to the same rate)
• Data bits: 8
• Parity: none
• Stop bits: 1
• Flow control: none
Alicat’s Serial Terminal Application
Alicat’s Serial Terminal is a preconfigured program for serial communications functioning much like the older Windows®
HyperTerminal.
Download Serial Terminal for free at alicat.com/drivers. Once downloaded, simply run SerialTerminal.exe. Enter the 
port number to which your device is connected and the baud rate of the pressure controller. The default baud rate is
19200, but this is adjustable by entering the RS-232 Serial menu on your pressure controller (page 18).
✓
Note: In the following examples, indicates an ASCII carriage return (decimal 13, hexadecimal D). For many devices, this
is the same as hitting the Enter key. Serial commands are not case-sensitive.
Polling Mode
Your controller is shipped in polling mode with a unit ID of A, unless requested otherwise. Each poll returns one line of
data every time you request it. To poll, simply enter its unit ID.
Poll the device: [unit ID]
Example: a(polls unit A)
You can change the unit ID of a polling device by typing:
Change the unit ID: [current unit ID]@=[desired unit ID]
Example: a@=b(changes unit A to unit B)
The front panel menu can also be used to change the unit ID (page 18). Valid IDs are letters A–Z, and up to 26 devices
may be connected at a time, as long as each unit ID is unique.