GA-180 Gas Detector

Operation and Maintenance Manual

The information contained in this manual was current at the time of printing. The most current versions of all

Hydro Instruments manuals can be found on our website: www.hydroinstruments.com

GA-180 Rev. 9/25/15

1

2

GA-180

Gas Detector

Operation Manual

Table of Contents

I. Installation

A. Monitor Installation ..................................................................................3

B. Sensor Installation .....................................................................................3

C. Battery Backup Installation .......................................................................4

II. Operation

A. Navigating the Controller........................................................................11

B. Operating Screens and Settings ..............................................................11

C. Configuring a Sensor Channel ................................................................12

D. Installing and Configuring Temperature .................................................18

E. Alarms and Outputs ................................................................................18

F. Modbus Communication .........................................................................22

G. Response Checks (Bump Testing) ..........................................................22

III. Troubleshooting

A. Installation Check ...................................................................................23

B. Symptoms, Likely Causes, and Suggested Responses ............................23

C. Explanation of Responses .......................................................................24

Figures

1a. Sensor Installation (heavy gases) ............................................................3

1b. Sensor Installation (light gases) ..............................................................3

2. Remove Calibration Cap .........................................................................4

3. Wiring Diagram up to 2 sensors, No Battery, No Thermocouple ...........5

4. Wiring Diagram up to 4 sensors, No Battery, No Thermocouple ...........6

5. Wiring Diagram up to 4 sensors, Battery, No Thermocouple .................7

6. Wiring Diagram up to 4 sensors, No Battery, Thermocouple .................8

7. Wiring Diagram up to 2 sensors, Battery, Thermocouple .......................9

8. Wiring Diagram (inside of door) ...........................................................10

9. Calibration Cap .....................................................................................14

10. Sensor and Calibration Kit ....................................................................14

11. GA-180 Operating Screens ...................................................................15

12. GA-180 Configuration Screens .............................................................16

13. GA-180 Modbus Configuration and Node Enable Screens...................17

14. External Alarm Light and Horn .............................................................21

15. Bump Testing (Chlorine Gas Example) ................................................22

Tables

1. Standard Ranges For Hydro Instruments Gas Sensors ..........................13

2. Relay Options for Common Relays (33 & 34) ......................................19

3. Relay Options for Sensor Relays (1-32) ...............................................19

I. INSTALLATION AND OPERATION

A. Monitor Installation

All monitors are able to accept either 120 VAC or 240 VAC single phase power at 50-60 Hz. When connecting A/C power it is imperative that the power source is well grounded. Improper grounding will disrupt proper operation of the unit.

Warning: Ensure source power is disconnected from main power, prior to making the instrument connection.

Monitors are NEMA 4X rated and should be installed at/near eye level and protected from exposure to direct sunlight and rain. The monitor should be installed near, but outside of the chemical storage room it is monitoring (see Figure 1a and 1b). Four 5 ⁄

16

" DIA through holes are provided on the enclosure for mounting the monitor against the wall.

FIGURE 1a FIGURE 1b

B. Sensor Installation

Refer to Figures 1a and 1b for more information.

1. Determine a suitable mounting location. For monitoring gases heavier than air, the sensor should be placed approximately 12-24 inches from the floor. For gases lighter than air, the sensor should be placed 12-24 inches from the ceiling. Do not place sensor in any location where it could become wet. This will damage the sensor.

2. Attach the enclosure to the wall using two 1 ⁄

4

"-20 mounting screws (recommended).

3. Remove sensor calibration cap. Store this cap in a known location as it is necessary for calibration when using a span gas. See Figure 2.

4. If necessary, open the sensor enclosure front cover and reconnect the signal wires. Connect

Red to Red and Black to Black on the terminal strip inside the sensor enclosure. Replace enclosure front cover and be sure to check that the gasket is evenly sealed around the enclosure. Also tighten the liquid tight fitting.

5. If necessary, connect the signal wire to the appropriate terminals. Refer to Figures 3, 4, 5, 6, and 7 so that you can connect the sensor to the right channel. The Black wire will connect to

AI1 or AI2 and the red wire will connect to V+ depending on the required channel number.

3

6. Connect GA-180 main power, allow sensor to stabilize.

7. Configure the sensor channel. See section II.C.

8. Perform a bump test on all sensors installed on the monitor. Confirm sensor has appropriate response to the test gas.

FIGURE 2

C. Battery Backup Installation

1. Disconnect A/C power before beginning this procedure.

2. Insert the battery into the enclosure by removing the surface protection tape and placing the

Velcro strips on the enclosure back plate. The battery should be installed so that the leads are facing up.

3. Identify the positive (+) and negative (-) leads on the battery. Remove the plastic protectors on the battery leads and connect the positive lead of the battery to the “BAT +” terminal on the battery backup board (MB101). Connect the negative lead of the battery to the “BAT –” terminal on the battery backup board (MB101).

4. Ensure that the appropriate 24 VDC from the power supply is connected to the appropriate PS + and PS- terminal. For units with battery backup, the DC power must go into these terminals for proper operation and detection of A/C power failure.

5. If necessary, enable battery backup on relevant sensor channels. Use the screen tree (Figure 10) to access the relevant screens. Cycle the power to save the enabled battery backup setting.

Note: Battery 1 will need to be enabled to back up sensors 1-4, Battery 2 will need to be enabled to back up sensors 5-6, Battery 3 will need to be enabled to back up sensors 7-12, and Battery 4 will need to be enabled to backup sensors 13-16. For example, if a system is ordered with 8 sensors then two batteries will need to be installed (into their respective enclosures). Battery 1 and Battery 2 will need to be enabled. If a unit was purchased at the factory to have battery backup this will have already been done.

4

*Remote acknowledge and 4-20 mA outputs must also have appropriate V- (GND) connection

Relays shall be wired in either a normally open (NO) or normally closed (NC) arrangement

GA-180 WIRING DIAGRAM

DATE: MAR 2015

DWG NO: GA-180-1

5

6

CB-8RELAY (MB108)

RELAY 33

RELAY 34

CB-2RELAY (MB123)

RELAY 8

RELAY 7

RELAY 6

RELAY 5

RELAY 4

RELAY 3

RELAY 2

RELAY 1

24VDC FROM POWER SUPPLY

*REMOTE ACKNOWLEDGE

*SENSOR 4 - 4-20 mA OUTPUT

*SENSOR 3 - 4-20 mA OUTPUT

*SENSOR 2 - 4-20 mA OUTPUT

*SENSOR 1 - 4-20 mA OUTPUT

CB-2X2MA (MB122)

CB-2X2MA (MB122)

RED

BLACK

BLACK

RED

SHIELD

*Remote acknowledge and 4-20 mA outputs must also have appropriate V- (GND) connection

Relays shall be wired in either a normally open (NO) or normally closed (NC) arrangement

RED

BLACK

BLACK

RED

SHIELD

SENSOR 2 INPUT

SENSOR 1 INPUT

SENSOR 4 INPUT

SENSOR 3 INPUT

GA-180 WIRING DIAGRAM

DATE: FEB 2015

DWG NO: GA-180-2

CB-8RELAY (MB108)

TO BATTERY

* WARNING: Reverse connection of + and - battery leads will destroy the MB101 Battery Board.

24VDC FROM

POWER SUPPLY

CB-BAT (MB101)

RELAY 4

RELAY 3

RELAY 2

RELAY 1

RELAY 8

RELAY 7

RELAY 6

RELAY 5

CB-2RELAY (MB123)

CB-2X2MA (MB122)

CB-2X2MA (MB122)

RED

BLACK

BLACK

RED

SHIELD

RED

BLACK

BLACK

RED

SHIELD

*Remote acknowledge and 4-20 mA outputs must also have appropriate V- (GND) connection

Relays shall be wired in either a normally open (NO) or normally closed (NC) arrangement

*SENSOR 4 - 4-20 mA OUTPUT

*SENSOR 3 - 4-20 mA OUTPUT

*SENSOR 2 - 4-20 mA OUTPUT

*SENSOR 1 - 4-20 mA OUTPUT

RELAY 34

RELAY 33

*REMOTE ACKNOWLEDGE

SENSOR 2 INPUT

SENSOR 4 INPUT

SENSOR 1 INPUT

SENSOR 3 INPUT

GA-180 WIRING DIAGRAM

DATE: FEB 2015

DWG NO: GA-180-3

7

8

CB-8RELAY (MB108)

THERMOCOUPLE INPUT

HIGH TEMPERATURE ALARM

CB-THERM (MB141)

YELLOW

RED

CB-2RELAY (MB123)

CB-2X2MA (MB122)

CB-2X2MA (MB122)

RED

BLACK

BLACK

RED

SHIELD

RED

BLACK

BLACK

RED

SHIELD

*Remote acknowledge and 4-20 mA outputs must also have appropriate V- (GND) connection

Relays shall be wired in either a normally open (NO) or normally closed (NC) arrangement

RELAY 8

RELAY 7

RELAY 6

RELAY 5

RELAY 4

RELAY 3

RELAY 2

RELAY 1

24VDC FROM POWER SUPPLY

*SENSOR 4 - 4-20 mA OUTPUT

*SENSOR 3 - 4-20 mA OUTPUT

*SENSOR 2 - 4-20 mA OUTPUT

*SENSOR 1 - 4-20 mA OUTPUT

RELAY 34

RELAY 33

*REMOTE ACKNOWLEDGE

SENSOR 2 INPUT

SENSOR 4 INPUT

SENSOR 1 INPUT

SENSOR 3 INPUT

GA-180 WIRING DIAGRAM

DATE: FEB 2015

DWG NO: GA-180-4

CB-8RELAY (MB180)

TO BATTERY

TO POWER SUPPLY

CB-BAT (MB101)

RELAY 8

RELAY 7

RELAY 6

RELAY 5

RELAY 4

RELAY 3

RELAY 2

RELAY 1

24VDC FROM POWER SUPPLY

HIGH TEMPERATURE ALARM

*SENSOR 2 - 4-20 mA OUTPUT

*SENSOR 1 - 4-20 mA OUTPUT

RELAY 34

CB-2RELAY (MB123)

CB-2X2MA (MB122)

CB-THERM (MB141)

YELLOW

RED

RELAY 33

*REMOTE ACKNOWLEDGE RED

BLACK

BLACK

RED

SHIELD

THERMOCOUPLE INPUT

SENSOR 2 INPUT

SENSOR 1 INPUT

*Remote acknowledge and 4-20 mA outputs must also have appropriate V- (GND) connection

Relays shall be wired in either a normally open (NO) or normally closed (NC) arrangement

GA-180 WIRING DIAGRAM

DATE: MAR 2015

DWG NO: GA-180-5

9

10

FIGURE 8: Wiring Diagram (inside of door)

II. OPERATION

A. Navigating the Controller

The GA-180 is provided with a Nema 4x, 2 line alphanumeric display controller that will display and output all important features and conditions. Navigating the controller is done by the use of four push button keys. The push button functions are described below.

key: Cycles to the previous screen.

key: Cycles to the next screen.

key: Increases/changes value, also used to enter screens.

key: Decreases/changes value.

Note: When adjusting parameter values, the number displayed is automatically saved upon leaving the screen. Thus no “enter” button is needed.

Password: All editable features of the GA-180 are password protected to prevent the unwanted tampering of the gas detector settings. To access these screens the correct password must be entered to proceed. The password for the GA-180 is “180”.

B. Operating Screens and Settings

This section gives a description of the operating screens and settings for each channel. To determine how to access each of these screens, use Figure 11.

stabilize without the program running to prevent unwanted tripping of alarms and relays. Once, the five minutes has expired the program will begin. The key can also be pressed to bypass the countdown and begin the program.

channel. If one or both channels are activated on a particular screen, then that screen will appear.

The plug and battery symbol represent A/C power and battery power respectively. A solid symbol represents stable power. A blinking symbol represents loss of, or low power. If the battery symbol does not appear than the battery backup is not enabled.

only appear if the thermocouple channel has been enabled.

GA-180. Pressing the key will activate the horn. Pressing the key will trip the relays.

sensor channel is in, if any. Typical statuses would be “Normal”, “Danger”, “Alarm”, or “Error”.

Refer to Sections II.E and III for alarm warning explanations and corrective actions.

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(relays, thermocouples, battery backups) the main display CPU will request information from the relevant circuit boards to display and operate properly. The GA-180 is able to detect if any boards on this system are not communicating properly and address the user for immediate correction. Communication statuses will be “Normal” or “Error”. Refer to Sections II.F for more details.

has exceeded the high temperature alarm setting. Status is either “Normal”, “Alarm High”, or

“Alarm Fail”. Refer to Section II.D for more details

Using the and keys, the password may be entered. The password for this unit is “180”.

C. Configuring a Sensor Channel

After the correct password has been entered, press to proceed to the configuration mode. Using the and keys, select the “sensor” option so that it is blinking and press the key to proceed to the channel configuration settings.

This section gives a description of the configuration screens and settings for each channel. To determine how to access each of these settings, use Figure 12.

channel. The GA-180 can accept up to 16 separate channel inputs. Use the and keys to select the relevant channel. Once the relevant channel is blinking, press to enter the sensor channel settings. All screens will be identical regardless of the channel selected. Settings will be adjusted and saved to each independent channel.

the high set, the channel low set is the point above which the “Danger” alarm will activate. The high set is the point above which the “Alarm” alarm will activate.

In the falling alarm configuration; in which the low set is greater than the high set, the channel low set is the point below which the “Danger” alarm will activate. The high set is the point

below which the “Alarm” alarm will activate.

Settings are adjusted using the and keys. Once the alarm levels are set press to proceed to the next screen.

0 represents non-latching and 1 represents latching. These values can be adjusted using the and keys. When latching is selected and a high alarm occurs, the alarm will stay in an alarm state until the user has acknowledged it, even if the condition has since been alleviated.

The high alarm for each channel can also be set to failsafe or non-failsafe. 0 represents nonfailsafe and 1 represents failsafe. When failsafe is selected, the high alarm relay becomes energized, in effect making the N.O. contact closed. Therefore should power be lost the relay will trip/activate.

in alarm state before the relays and other alarm features activate. This setting is adjustable from

0-60 seconds, with 5 seconds as the recommended default.

periodically drift from 0.0 ppm even though no gas is present. To reset this press the key to

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increase the value and press the key to decrease the value on this screen. The keys must be pressed one at a time to move the value, pressing and holding will have no effect. Wait at least

10 seconds after a new zero has been entered to confirm signal stability. A bump test should be performed after calibration.

Warning: The zero calibration should only be adjusted if the sensor is offset by 5% or less from zero. Confirm that no gas is present prior to recalibration and always ensure adequate safety procedures are enacted to confirm there is no gas present. If the value is offset by more than 5% do not recalibrate and consult Hydro Instruments for more information.

changing the gas type from “OFF” to one of the following options “NH

“Cl

2

”, “ClO to detect.

2

”, “CO”, “H

2

”, and H

2

3

”, “O

2

”, “O

3

”, “SO

2

”,

S”. The gas type must match that which the sensor is designed so that it will match the full scale of the sensor output connected to the channel. Should the two outputs be misaligned, improper operation will result. Standard full scales for sensors supplied by Hydro Instruments can be seen in Table 1. If unsure about the full scale output of a sensor, please contact Hydro Instruments.

TABLE 1: Standard Ranges For Hydro Instruments Gas Sensors

Gas Type

Chlorine (Cl

2

)

Sulfur Dioxide (SO

2

)

Ammonia (NH

3

)

Other

Sensor Range

0-10 ppm

0-30 ppm

0-100 ppm

Consult Factory calibration upon installation setup. Span calibration is rarely required, however, it may be required or desired to perform span calibrations periodically over the life of the sensor. If calibration is to be carried out, then the appropriate span gas calibration kit must be purchased

(Figures 9 and 10).

8a. The calibration cap must be installed on the sensor and connected as indicated in Figures

9 and 10. Span gas must be allowed to flow at 500 cc/min for at least 1 or 2 minutes until the displayed reading stabilizes. The reading on this screen should be adjusted to match the ppm value of the span gas being used. Use the key to increase the reading of the key to decrease the reading. Press and release the keys one at a time. Do not press and hold the keys. After adjusting, wait 10 seconds to confirm that the reading is stable before proceeding to the next step.

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FIGURE 9: Calibration Cap FIGURE 10: Sensor and Calibration Kit

After passing over the sensor membrane the span gas will exit through the other port on the calibration cap.

Ordering Information

Product

Number

Description

GA-CK-CL2-10 Calibration Kit – 10 PPM Chlorine Gas with Regulator

GA-CRS-CL2-10 Replacement Sensor – 0-10 PPM

Chlorine

Note: The sensor is shipped with the calibration cap already installed. After calibration the calibration cap should be removed for normal use. Do not dispose of the calibration cap as it will have to be reinstalled and used for any further sensor calibrations.

used for remote monitoring/indication of gas residual. Although each channel is calibrated using

NIST certified equipment, it may be necessary to adjust the output of from the controller to match the input of the remote system. This screen allows the user to adjust the A/D count that outputs the 4 mA signal. Pressing the key will increase the current output and pressing the key will decrease the output.

screen allows the user to make minor adjustments to the A/D value that controls the 20 mA output. Pressing the key will increase the current output and pressing the key will decrease the output.

the sensor. The filter time can be set anywhere from 0-60 seconds using the and keys.

The recommended factory default value is 5 seconds.

points and their corresponding A/D values for diagnostic purposes.

and current output for a particular sensor.

14

1

Sensor Startup 5:00

Press + To Exit

2

01 CL2 0.0 PPM

02 CL2 0.0 PPM

2A*

03 CL2 0.0 PPM

04 CL2 0.0 PPM

2G*

15 CL2 0.0 PPM

16 CL2 0.0 PPM

3*

4

Temperature

75 F

Test Operation

+ Horn - Relays

5

01 Status: Normal

02 Status: Normal

5A*

03 Status: Normal

04 Status: Normal

5G*

15 Status: Normal

16 Status: Normal

6*

7*

8

Comm Status

Normal

Temperature Status

Normal

Enter Password

180

* These screens will only appear if the relevant sensor, temperature, and/or communication settings have been enabled.

15

16

FIGURE 12: GA-180 Configuration Screens

Press with

“Sensor” blinking

Enter Password

180

Setup

Sensor Temp

Press with

“Temp” blinking

1

2

Configure Channel

Ch_

Ch_ Lo Set = 1.0 ppm

Hi Set = 2.0 ppm

3

4

Ch_ Alarm Latch = 0

Failsafe = 0

Ch_ Alarm Delay

5 Secs

5

Ch_ Zero Calibrate

0.0 PPM 0%

6

Ch_ Gas Type = CL2

Units = ppm

7

8

9

Ch_ Full Scale

10 ppm

Ch_ Span Calibrate

5.0 ppm 50%

Ch_ 4mA Output Cal

193

10

Ch_ 20 mA Output Cal

956

11

Ch_ Filter Time

5 Secs

12

Zero = 800 0.0 ppm

Span = 2000 5.0 ppm

13

Ch_ Live A/D = 810

0.0 ppm 4.0 mA

Press and hold the down arrow on the

Ch_Alarm Delay screen to bypass screen 5 and access screens 6-13.

T1 Temp Units

F

T2

Temp Alarm = 120 F

Alarm Delay = 5 Secs

1

2

3

4.1

With “Sensor” blinking, press and hold the key until screen 1 appears

Modbus Baud=250000

Node=1 Data=8/N/1

Relay 33

Any Sensor Low

Relay 34

Any Sensor High

Enter Password

180

Setup

Sensor Temp

Press and hold the on the Relay 33 screen to bypass screen 3 and access screens 4.1-14.

Relay 1

Ch1 Low

4.32

5

6

7

8

9

Relay 32

Any Senor High

Thermocouple Enable

No

Relay 33-34 Enable

No

Relay 1-8 Enable

No

Battery 1 Enable

No

Relay 9-16 Enable

No

10

11

12

Battery 2 Enable

No

Relay 17-24 Enable

No

Battery 3 Enable

No

13

14

Relay 25-32 Enable

No

Battery 4 Enable

No

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D. Installing and Configuring Temperature

1. Determine adequate mounting location for thermocouple and support bracket. Mount the support bracket to a wall or fixture using appropriate hardware (hardware not supplied with GA-180).

2. If necessary, connect the thermocouple to the thermocouple circuit board using the TI + and TI- terminals. Connect the Red wire to TI- and the Yellow wire to TI+. Only type K thermocouples can be used on the GA-180.

3. If necessary, connect the thermocouple board (MB141) to the display through the Modbus connector.

4. If necessary, enable the thermocouple communication. Follow the screen tree (Figure 13) to navigate to the screen “thermocouple enable”. Change to yes by pressing the key and cycle the power. Unless you turn the power off and back on, the change will not take effect.

5. Check communication by confirming that the appropriate live temperature screen and temperature alarm screen have appeared in the correct area (Figure 11).

6. Using the screen tree (Figure 12), navigate to the “Temperature Units” screen. Units can be adjusted between “F” for Fahrenheit and “C” for Celsius. Select the appropriate unit using the

and keys.

7. Press and select the high temperature alarm set point. Values can be selected anywhere from

0-255 F/C. At a minimum, Hydro Instruments recommends the alarm setting be at least 20ºF lower than the fusible plug melting temperature of the gas containers. Contact your chemical supplier to confirm the temperature for the fusible plug melting point. Other equipment or local restrictions may apply. Select the appropriate value by pressing the and keys.

8. Press and select the alarm delay time. This setting sets the amount of time the temperature must remain above the alarm setting before the alarm will activate. Values can be set in the range of 0-60 seconds and values are adjusted using the and keys. Press to exit the thermocouple configuration.

E. Alarms and Outputs

a. Normal – The sensor is operating normally and is below the “Danger” set point.

b. Danger – The sensor reading has reached or exceeded the “Lo Set” level, but is lower than the

“Hi Set” level. Refer to Section II.C and Figures 10 and 11 for additional details.

c. Alarm – The sensor reading has reached or exceeded the “Hi Set” level. Refer to Section II.C and Figures 11 and 12 for additional details.

d. Error – The sensor signal has been lost.

Alarms: The GA-180 comes with two common relays and eight sensor relays to every four sensors ordered. The two common relays (relay 33 and relay 34) can be configured to any of the alarm conditions outlined in Table 2. The sensor relays can be configured to any of the alarm conditions outlined in Table 2. All relays are dry contacts with a maximum power rating of 10 A.

To change any alarm relay to an alarm condition outlined in Tables 2 & 3. Follow the configuration sceen layout screen tree. Once at the appropriate relay, change the alarm condition by pressing the

key. Cycle the power to save the new condition.

18

TABLE 2: Relay Options for Common Relays (33 & 34)

Relay

Relay 33 & 34

Options

Any Sensor High

Any Sensor Low

Any Sensor Signal Loss

Loss of AC Power (must have battery backup)

Loss of / Low Battery Power (must have battery backup

TABLE 3: Relay Options for Sensor Relays (1-32)

Relay

Odd Numbered

Even Numbered

Options

Ch_ low alarm

Any sensor low

Any sensor high

Any sensor signal loss

Loss of A/C Power (must have battery backup)

Loss of / Low Battery Power (must have battery backup)

Ch_ High alarm

Any sensor low

Any sensor high

Any sensor signal loss

Loss of AC Power (must have battery backup)

Loss of / Low Battery Power (must have battery backup)

19

20 illuminate and the relay will be activated. To acknowledge an alarm (and deactivate the relay) for all sensors in the “Alarm” condition press the key. Pressing the key once will inactivate the horn, pressing the key twice will inactivate the relay. Alarms can also be acknowledged remotely through the use of a SCADA system / PLC. To do this, connect a contact input to the

DI1 input terminal on the 2 relay board (MB123) and to a relevant ground. Connecting the input once will inactivate the horn, connecting the input twice will inactivate the relay.

Note: Even after acknowledging the alarm, both LEDs will remain illuminated until the alarm condition has been removed.

level alarm), then the GA-180 will automatically configure the channel as a rising alarm.

Therefore, if the sensor reading is higher than the Danger or Alarm setting the GA-180 will activate the appropriate alarm(s). To configure a sensor rising/falling alarm, follow the steps outlined in Section II-C.

level alarm), then the GA-180 will automatically configure the channel as a falling alarm.

Therefore if the sensor reading is lower than the Danger or Alarm setting the GA-180 will activate the appropriate alarm(s). To configure a sensor rising/falling alarm, follow the steps outlined in Section II-C.

level alarm) relay will become normally energized. This will cause a reversal of the NC/

NO connections. Therefore, the normally closed connection will be open unless an alarm condition is present or power is lost. To configure a sensor failsafe alarm, follow the steps outlined in Section II-C.

ordered. This output signal will represent the current gas residual value. See Figures 3, 4, 5, 6, and 7 for 4-20mA output wiring locations.

FIGURE 14

External Alarm Light and Horn

An external alarm light with combination audible horn is an electronic device designed to alert operators and other personnel both visually and audibly to a specific danger.

Most commonly an external alarm light and horn is used with a gas leak detector to warn of gas leaks before entering a structure or room.

Features

• Single compact unit for wall mounting

• Rotating strobe light with red housing

• Audible horn

• Weather resistant

Available in GA-AL-110 (110V AC) and GA-AL-220

(220V AC).

Optional accessory for use with the Hydro

Instruments gas leak detection equipment.

NOTE: The diagram illustrates a normally open connection.

Power

Source

Gas Alarm

Relay Switch

NC1

CO1

NO1

Jumper wire

Alarm Light

21

F. Modbus Communication:

Modbus RS-485 communication. The GA-180 is equipped for remote display and communication using the modbus RS-485 standard. To do this, you must define the node, baud rate and parity of the system. For more information on how to setup modbus refer to the Modbus Installation and Instruction manual. The Modbus Installation manual can be downloaded from the Hydro

Instruments website (www.hydroinstruments.com). Printed copies are available upon request.

G. Bump Testing

To verify responsiveness, the gas sensors can be bump tested (exposed to a small amount of the target gas) in order to test the reaction of the sensor. A plastic squeeze bottle is provided with each gas detector for this purpose (Figure 15). It is suggested that bump testing be done at quarterly intervals, however required frequency is determined by environment, conditions, number of and severity of leaks. Proper bump testing will not substantially degrade the sensor or shorten sensor life. Figure 15 diagrams a bump testing procedure for chlorine gas. Contact Hydro Instruments for other bump testing procedures should the sensor be for something other than chlorine gas.

FIGURE 15: Bump Testing (Chlorine Gas Example)

Bump Test Bottle

For Chlorine sensors bottle contains 2 parts

NaClO solution (bleach) and 1 part vinegar

22

III. TROUBLESHOOTING

A. Installation Check – Review each of the following points first.

a. Sensor enclosure cover must be securely fastened to protect against corrosion of the transmitter board etc.

b. Sensor must be mounted at a height that is according to Figures 1a and 1b.

c. Sensor must be mounted so that (rain) water cannot come into contact with the sensor element.

Water coming into contact with the sensor element will damage the sensor and cause the need for sensor replacement. Generally, water damage will cause the sensor to have an above zero reading that will not return to zero.

d. Ensure that the sensor calibration cap has been removed completely. See Figure 2.

a. Monitor should be installed at eye level in a location that is suitable for personnel to check the sensor status before entering the chemical storage room.

b. Monitor should be mounted in a location that is protected from rain and it is recommended that it should not be mounted under direct sunlight.

c. Monitor enclosure bolts must be securely fastened and wiring seal tights must be plugged if not used in order to protect against corrosion of the circuit boards etc.

d. Ensure that the alarm relay output and/or 4-20mA outputs are wired according to Section II.E and Figures 3, 4, 5, 6, and 7.

B. Symptoms, Likely Causes, and Suggested Responses

Symptoms Likely Causes Suggested Responses*

Slightly off zero in air Inaccurate zero calibration Perform zero calibration

Zero & no response with

Alarm Status: Normal

False alarm and no display response with Alarm Status:

Error

1. Calibration cap not removed

2. Wrong span calibration

1. Sensor disconnected

2. Sensor damaged

1. Remove calibration cap

2. Correct span calibration

1. Check sensor wiring

2. Replace the sensor

High reading or reading that won’t return to zero

Sensor damaged Replace the sensor

Blank display

1. Lost A/C power

2. Damaged circuit board

3. Blown fuse

1. Check A/C Power

2. Replace circuit board

3. Replace fuse

* See Section III.C for a more detailed explanation of the suggested responses.

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C. Explanation of Responses

Refer to Section II.C.5 and Figure 12.

and storage, but must be removed upon installation. If the sensor cap is not removed, then there will be no response or a very slow response. Refer to Section I.B.3 and Figure 2.

air with zero target gas) then this will cause the readings to be inaccurate. Unless you intend to perform the span calibration and have a span gas calibration kit, do not touch the and keys if you enter the span calibration screen. See Section II.C.8 and Figures 9, 10, and 12.

message, then the sensor may not be connected to the monitor. Check the wiring from the circuit board in the monitor to inside the sensor enclosure. See Figures 3, 4, 5, 6, and 7.

gases will eventually cause failure of the sensor. If water is allowed to contact the sensor element this will also eventually cause failure of the sensor. Under normal circumstances a sensor life is typically 2 years or more. However, lightning, other power surges, chemical leaks, and contact with water can all cause sensor failure. Replacement sensors are easily installed with the quick disconnect fitting.

wrong terminals, by lightning, other power surges, or by corrosion. If you believe that the circuit board is damaged, then contact the factory and your local sales representative. Refer to Figures

3, 4, 5, 6, and 7.

replace if necessary.

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