AirTest CN9000 Series User manual

1
AirTest Model CN9000 Series Sensor Controller
AirTest Model CN9000 Series Sensor Controller
THEORY OF OPERATION
Abasic CN9000 configuration consists of Input/Process/Display combination modules, a3relay output module,
a12 slot interconnect board, and apower supply sized to system requirements. Refer to color image for
component identification.
INPUT MODULE
An input module provides aconnection for asensors data signal and power requirements. Circuitry is provided
to condition the sensor signal for processing. An input module can have any one of avariety of input
specifications to accommodate any sensor signal output type including temperature, pressure etc. These
signals are then output to other modules via the interconnect board. Because power requirements between
sensors can also vary, input modules can be configured to supply virtually any low voltage power source.
Custom input modules may interface with override switches or keypads.
The basic input module has connections for 4-20mA input signal using a100 ohm current sensing load, 12 volt
DC sensor power source and an AC power source (optional).
PROCESS MODULE
Aprocess module can input signals on the interconnect board and perform some form of analysis or further
conditioning to the signal and in turn generate and direct an output signal back to the interconnect board to be
used by other modules. Processing can include generation of signals to trip relays, turn on status LED’s or
display comprehensive alphanumeric data on an LCD panel. The basic process module is part of the basic input
module.
DISPLAY MODULE
A display module can take many forms with the common theme of providing visual information, the most
common being simple LED’s.
OUTPUT MODULE
An output module inputs signals from the interconnect board and directs them to output devices as required by
the end user. An output module can provide the end user with asimple contact closure or acomplex data
stream that can be used by abuilding management system. The AirTest CN9000 controller is also not limited by
the number and output types per system configuration. Typical output modules provide one or more dry contact
relays, LED contact closure indicators and wiring terminals.
FEATURE MODULE
Feature modules allow intermediate logic processing of system signals. These signals can be any combination
of inputs from the interconnect board or onboard user wiring terminals. Processed signals can then be output to
the interconnect board for use by other modules and/or to user wiring terminals for connection to external
devices.
One example would be amodule that processes ahigh gas concentration level from an input/process module
and makes adry contact relay closure to power ahorn. If apush button is pressed (input through wiring
terminals) the horn is silenced for auser selectable time period.
INTERCONNECT BOARD
This board provides aconnection path between modules as well apower. The base interconnect board allows
connection for up to 12 modules of any type. Multiple interconnect boards can be wired together to expand the
system beyond 12 modules.
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2
AirTest Model CN9000 Series Sensor Controller
THEORY OF OPERATION continued
ATYPICAL SYSTEM WALK THROUGH
The external sensor’s power and 4-20mA status signal wires are connected to the input modules wiring
terminals. Processing of the 4-20mA takes the form of acomparator circuit where it’s digital output signal
changes state when the voltage across the 100 ohm current sensing resistor is greater than areference voltage.
The voltage at which the state change occurs is called the “trip point”.
The trip point voltage can be a fixed value, as in the sensor fail detect (out of operating range) circuit or be
variable through user adjustable trim potentiometers. The base input module incorporates four comparator
outputs, 2 of which have user settable trip points and the remaining 2 are have fixed trip points for high and
low sensor fault conditions. The 2 fault state comparator outputs are tied common to allow one fault
condition signal. The resulting 3 digital signals are placed onto 1 of 16 available signal channels on the
interconnect board through jumpers on the input module.
The signals available on the interconnect board are used by the output module. Channel selection is
accomplished but setting the appropriate jumper on the output module. There are 3channel selection blocks, 1
for each of the 5amp relays.
Common controller configurations use 3relays as the final output to external devices. Aventilation system is
activated by the contact closure of arelay when alow gas level is detected, while asecond relay activates an
audible and/or visual alarm when the gas level reaches ahigher level indicating apossible problem with the
ventilation system. The third relay is used to signal afault with the system such asensor signal loss which may
indicate asensor fault or abreak it sensor wiring. In any case it is important to incorporate basic fault detection
into any safety system.
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3
INSTALLATION
The controller is designed for wall mounting in acontrol room or working area. The enclosure incorporates asub
panel assembly and window.
1. CONTROLLER INSTALLATION/MOUNTING
Securely mount the controller to the wall using four (4) mounting screws with lock washers and nuts. Make
sure there is room for the door to open.
2. INTERCONNECT WIRING
Interconnect wiring is identified in the customer wiring diagram drawings in this manual. It is recommended that
all wiring is shielded and common shielding practices be used for installation to reduce the possibility of radio
frequency interference.
Step 1: Connect sensor to the interconnect cable. Record wire colours and what terminals they are connected
to. See sensor information as to number of wires used and their connection.
Step 2: Terminate the other end of the interconnect cable from sensors at the connectors located inside the
controller on the upper right of the motherboard. Observe correct polarity between sensor and
controller connections. Failure to do so may result in damage to amplifier circuits.
Interconnecting wiring between controller and sensors
3. ALARM RELAY OUTPUTS
Step 1: Terminate wiring to alarm output connectors as identified in customer wiring diagram drawing.
Step 2: Terminate power supply input wiring as identified in customer wiring diagram.
4. PREPARATION FOR OPERATION
Step 1: Check all wiring for correct polarity and good terminal connections.
Step 2: Apply power and observe visual indicators.
-Input Module indicator lights may cycle between off, green, red and yellow upon start up. Many
sensors will require astabilization period. Consult specification for the particular sensor
Step 3: Check voltage reading at each sensor.
This measurement will depend upon main power supply setting.
-+12 VDC to 14 VDC between (+) and (-) terminal connections.
5. INSTRUMENT START-UP
Step 1: Let the sensor settle after power has been applied. See sensor data for settling time.
Step 2: A zero air sample should be applied to each sensor to check absolute zero when acontinuous gas
background exists in the area where the sensor is installed.
NOTE: Airtest gas monitors are shipped calibrated and should not require any adjustment provided voltage
reading and operational tests give correct indication. However, it is recommended that acalibration
test be performed after installation.
Step 3: Testing of response to the presence of gas using atest sample or calibration sample of gas should be
applied to each sensor.
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4
CONTROLLER CALIBRATION
1. ALARM TRIP POINT ADJUSTMENT –By Voltage
To Set Alarm Trip Points
Step 1: Open the inner cabinet door of the Model 9000 controller to allow access to alarm adjustments.
Step 2: Using avoltmeter, connect to the black and the yellow (RTP1) testpoints.
Step 3: Adjust the RTP1 potentiometer until the DVM reads the desired value as recorded when calibration gas
was applied to the sensor.
The Input Module is normally set to operate from 0.4 to 2.0 VDC which is adirect correlation to the 4mA
to 20 mA signal produced by a4-20 transmitter. This allows for easy calculation of alarm set points. The
0.4 to 2.0 volts corresponds to 0ppm to max range ppm or in the case of the TR2000 0–200ppm CO.
2. ALARM TRIP POINT ADJUSTMENT –By Calibration Gas
Step 1: Open the inner cabinet door of the Model 9000 controller to allow access to low and high alarm
potentiometer adjustments.
Step 2: Apply to the sensor, calibration gas of aconcentration desired for low alarm relay activation.
Step 3: Adjust applicable “RTP1” potentiometer until the low alarm relay activates. (listen for “click” or watch relay
activation lights on the Output Module)
Step 4: Redo steps 2&3for the high alarm using calibration gas of aconcentration desired for high alarm relay
activation.
Step 5: Repeat steps 2through 4for each channel.
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5
CN9000 CONTROLLER SPECIFICATIONS
Channels: up to 17 inputs (and one Output Module) per Interface Board
Dim ensions: 12.6" W x 14.2" L x 8" D
(dimensions are based on a controller assembled for 11 analog inputs and 3 relay outputs)
Weight: 24 lbs.
Input Pow er: 120vac 50/60hz 1 Amp
-optional 220v 50/60hz.
-optional 12VDC, and/or 24VDC operation or backup pow er.
Input Pow er Fuse: 1 Amp (FastBlo)
Sensor pow er: 12VDC. at 0.2 amps per input.
-optional 24-28VAC
Operating Temperature Range: -30 Cto +65 C.
INPUT MODULE
Display: 3 colour LEDper Input Module
Indicators: -One 3 colour LED.
-POWER "ON" LED(GREEN) normally "ON".
-Relay Trip Point 1 (yellow ) normally "OFF".
-Relay Trip Point 2 (red) normally "OFF".
-SENSOR MALFUNCTION(fail) per channel (red) normally "OFF"
(fail relay normally energized.)
Input Im pedance -100 ohms
OUTPUT MODULE
Display: -each relay contact has LEDto indicate closure
Relay : -3 relays – each relay DPST 5 Amp non-latching
-All relays are configurable as RTP1 or RTP2.
WARRANTY
AirTest Technologies, Inc (thecompany) warrants theModel CN-9000, Controller to be free from defects in materials and workmanship under
normal useandservice for a period of oneyear. Thecompany’s obligationof this warranty shall be limited to therepair or replacement of any part
found to be defective.Thecompany shall notbe obligated to repair or replace units thatarefound to be in needof repair because of damage, (other
thannormal wear and tear), tampering or modification. The controller must be returned to AirTest suitably packaged and with freight prepaid.
Liability is limited to the replacement cost of a new unit. In no case shall the company be liable for any consequential or incidental damages
however caused. No agent, dealer or employee of thecompany has theauthority to increase or alter theobligations or limitations of this warranty.
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AirTest Model CN9000 Feature Module
This custom feature module incorporates a timing circuit, output relays and external input/output wiring
terminal block.
1 – Timing Circuit (Time Select Switch)
If the front panel pushbutton marked “Audible Acknowledge” is pressed the timer circuit silences the
audible horn for a period determined by the “Time Select Switch”. After the time period expires the
audible alarm will be enabled and will sound if the system detects a high gas level state.
The Time Select Switch is marked 0 through 9 and A through F (10 through 15) for a total of 16 positions.
Each position represents a 2 minute interval which is multiplied by the switch position value (0 through
15) to determine the audible silence time. If the switch is set to position A (value of 10) the silence time
would be 2 minutes X 10 or 20 minutes The maximum time would be 30 minutes at switch position “F”
(15 X 2 Min. = 30 Min.).
2 – Horn/Strobe Interlock Relays
Separate relays to drive the horn and strobe are provided to facilitate the audible silence function. When
a high gas level is detected relay 3 (marked on module in white) will activate and provide a grounding
(minus) signal to the horn and strobe. If the “Audible Acknowledge” button on the front panel is pressed
relay 2 will disconnect the grounding signal to silence the horn for a period determined by the Time
Selector Switch position.
3 – Input/Output Terminal Block
This terminal block provides connection points for the front panel switches, indicators, horn and strobe.
Refer to diagram below for details.
Input/Output Wiring Identification and Simplified Schematic.
Note: Symbols for connected devices are for quick reference only.
Refer to schematic diagram for more detail.
Acknowledge (Silence) Button
1
2
3
NC
NC
-12VDC Supply
Suuply
Fan 2 Switch
Horn Silence Relay Input
Horn Minus
Fan 1 & 3 & Damper Switch
+ -
+12VDC Supply
NC
-12VDC Supply
Suuply
Strobe Minus
- +
V+
V+
NC
V+
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AirTest Model CN9000 Feature Module
This custom feature module incorporates a timing circuit, output relays and external input/output
wiring terminal block.
Silence Timing Circuit
When the front panel pushbutton marked “Silence” is pressed the timer circuit silences the
audible horn for a period determined by the position of trim pot (1). After the time period expires
the audible circuit alarm will be enabled if the system detects a gas level above the Relay Trip
Point (RTP). The timer is adjustable from 0 to approximately 20 minutes. The image below
shows the trim pot set to offer a silence period of approximately 12 minutes.
LED (2) is illuminated during the silence period.
Terminal block (3) is custom wired and should not be modified unless instructed by AirTest or it’s
an authorized representative.
The 2 header pins (4) are connected to the front panel push button via an IDC plug.
1
2
3
4
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AirTest Model CN9000 Basic Input/Process Module Detail
This standard module incorporates a user wiring terminal block, trip point (TP) adjustment trimpots, TP output channel
selectors, a multi-colored LED status indicator and test points for connecting a Digital Volt Meter (DVM).
(1) – Wiring Terminal Block
A screw-less wiring terminal block provides connections for sensor power and 4-20 mA input. Two power sources,
typically 12-14 VDC and 24 VAC, are supplied for systems with mixed sensor types including loop powered
electrochemical sensors, 3 wire DC powered MOS or Catalytic bead sensors and 24 VAC powered IR CO2 sensors.
The power supplied to the terminals can be factory configured to many other standard or custom voltages. Refer to
Input/Output wiring for system specific details.
(2) – Input Signal Test Points
The 4-20mA input is terminated with a 100 ohm, 1% precision, current sensing resistor. To read the signal current of the
attached sensor connect the negative lead of a DVM (Digital Volt Meter) to the black ring terminal test point (common
ground reference) and connect the positive lead to the bare lead on the top of the current sense resistor. The use of small
alligator or flee clips is recommended. Multiply the voltage reading is by 10 to calculate the milliamp reading. For
example a reading of 0.40 volts would be 4mA. (0.40 x 10 = 4). Twenty milliamps would read as 2 volts on the DVM.
(2.00 x 10 = 20)
(3) – Relay Trip Point (RTP) adjustments and test points.
The standard input/process module incorporates 4 comparator circuits where 2 have user settable relay trip points or TP’s
for short. A TP is the point where a comparators single bit output changes to an active or inactive state when the rising or
falling sensor signal level passes a threshold level.
The voltage across the 100 ohm current sensing resistor is compared to a reference voltage. If the current sense voltage
level is higher than the reference voltage, the output signal of the comparator circuit is activated and will be available on
its’ Output Channel selector jumper block. Two comparators are used for sensor fault detection and have factory set TP
levels. See System specifications for more detail. These comparator outputs are combined and output to a single “FAIL”
channel selector.
The 2 remaining comparators have user adjustable TP’s through the turning of potentiometer screws (see 3a below). The
TP level for TP1 and TP2 can be read at yellow test points (see 3b below). In the image below, TP1’s yellow ring terminal
test point and level adjust potentiometer is located at the top of the board and is identified by the white lettering printed on
the circuit board, just to the left of the test terminal.
NOTE – Since a module can be plugged into the interconnect board on the left or right, the lettering and component
positions will be inverted to the images shown.
A TP’s voltage level can be read at it’s corresponding test point and be converted to a current level as described above.
To set a TP1 of 12mA connect the negative lead to the black common ground reference test point near the current
sensing resistor and set the voltage read at TP1 test point to 1.20 volts. (12mA / 10 = 1.20 volts)
NOTE – For correct operation of status indicator TP1 voltage level must be set lower than TP2 voltage level.
1
3a
2
3b
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AirTest Model CN9000 Basic Input/Process Module Detail
(4) – Output Channel Selector Block
Each comparators’ digital (on/off, 1/0) output signal can be assigned to any one of 16 interconnect signal lines referred to
as channels. A comparator output can use the same channel as another output to provide a logical “OR” configuration.
This allows for a common signal to be present when any (1 OR 2 OR …etc.) sensor level is above a TP. A typical system
will combine all Low level, all High level and all Fault TP’s signals to drive 3 individual Low, High and Fault/Fail dry contact
relays.
Each output channel selector block is identified by white lettering printed on the circuit board just to the left of each block.
NOTE – Since a module can be plugged into the interconnect board on the left or right, the lettering and component
positions will be inverted to the images shown.
Even though selection of a channel is totally arbitrary some logic should be applied to the decision. The factory default
settings are jumpers placed on selector position 1 (channel 1) for TP1, on selector position 2 (channel 2) for TP2 and on
selector position 16 (channel 16) for sensor Fail/Fault. These selector block pins are marked with white outlined
rectangles in the image below. Jumper pin positions or channels are identified with white numbers printed on the circuit
board. NOTE – Only the odd number pins are marked.
This feature is no longer available unless specified at order time. The channel selection is factory set (hard
wired) as required be system specification.
(5) – Module Status Indicator.
A multi-colored LED is provided as status indication of the four output states of the module.
State 1 – An LED that is not lit is an indication of a fault in the system. An “ON” signal is generated and placed onto
channel 16 (factory default) of the interconnect board. Refer to troubleshooting section on steps to resolve
this abnormal condition.
State 2 – No output signals are generated in this state.
State 3 – An “ON” signal is generated and placed onto channel 1 (factory default) of the interconnect board. This is a
normal condition as the long as it is expected that the sensor signal is at or above the TP1 level.
State 4 – An “ON” signal is generated and placed onto channel 2 (factory default) of the interconnect board. This is a
normal condition as the long as it is expected that the sensor signal is at or above the TP2 level.
State
Color
Description
4
Red
Sensor signal level is at or above TP2 level.
3
Amber
Sensor signal level is at or above TP1 level.
2
Green
Sensor signal in range and below all TP’s.
1
Off
Sensor signal is out of range or module has failed.
5
4
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AirTest Model CN9000 Basic Output Module Detail
Output Module
This standard module consists of three relays, terminal blocks, input channel selectors and relay status indicators. Relays are
Two Pole Single Throw type, with one pole NO (Normally Closed) and the other NC (Normally Closed).
This feature is no longer available unless specified at order time. The channel selection is factory set (hard
wired) as required be system specification.
The state of each relay contact is indicated by LED’s on board the Output Module. An illuminated LED indicates a closed
contact.
Refer to Input/Output Wiring sheet for more detail.
Interconnect Board
The Interface Board provides the interconnection between the Input Modules, the Output Modules, custom circuit boards
and any other future modules.
Power Supply
The Power Supply provided with the CN-9000 provides power for the CN-9000. Power supply size is determined by the
requirements of the sensors and accessories that will be powered by the system.
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