Danfoss DGS User guide

User Guide

Danfoss Gas Sensor Type DGS

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User Guide | Danfoss Gas sensor, type DGS

Contents

1. Intended use ...................................................................................................................................3

2. Introduction ....................................................................................................................................3

3. Installation and maintenance .......................................................................................................3

3.1 Technician use only! ............................................................................................................................................ 3

3.2 Regular Test .......................................................................................................................................................... 3

3.3 Location .................................................................................................................................................................. 3

3.4 Dimensions and appearance ............................................................................................................................ 4

3.5 Cable gland opening ........................................................................................................................................... 4

3.6 Board pinout ......................................................................................................................................................... 4

3.7 Installation instructions ..................................................................................................................................... 5

3.8 Installation Test .................................................................................................................................................... 6

3.9 Troubleshooting ................................................................................................................................................... 7

3.10 Power Conditions and Shielding Conceptions ..............................................................................................7

4. Operation ......................................................................................................................................9

4.1 Function of the keys and LEDs on the keypad .............................................................................................10

4.2 Setting / changing of parameters and set points .......................................................................................10

4.3 Code levels ...........................................................................................................................................................10

5. Menu overview .............................................................................................................................11

5.1 Error status...........................................................................................................................................................12

5.2 Alarm Status ........................................................................................................................................................ 13

5.3 Relay Status ......................................................................................................................................................... 13

5.4 Menu Measuring Values ...................................................................................................................................13

5.5 Display Parameters ............................................................................................................................................14

5.5.1 Software Version ................................................................................................................................... 14

5.5.2 Language ................................................................................................................................................ 14

5.5.3 LCD Function Check .............................................................................................................................14

5.6 Alarm Reset Settings .........................................................................................................................................14

5.6.1 Relay Reset .............................................................................................................................................. 14

5.6.2 Alarm reset duration ............................................................................................................................ 15

5.7 Alarm Settings ....................................................................................................................................................15

5.7.1 Room mode ............................................................................................................................................ 15

5.7.2 Alarm limits ............................................................................................................................................ 15

5.7.3 Alarm relay ............................................................................................................................................. 15

5.8 AO Settings ..........................................................................................................................................................16

5.9 Operating Data ..................................................................................................................................................17

5.10 Calibration ........................................................................................................................................................... 18

5.10.1 Zero calibration ..................................................................................................................................... 19

5.10.2 Gain calibration ....................................................................................................................................20

5.10.3 Zero point calibration of analogue output .....................................................................................21

5.11 Addressing ........................................................................................................................................................... 21

6. MODBUS menu survey .................................................................................................................22

7. Ordering ....................................................................................................................................24

2 | BC291049702513en-000201 © Danfoss | Climate Solutions | 2022.01

User Guide | Danfoss Gas sensor, type DGS

1. Intended use This document has the intent to provide the guidelines to avoid possible damages deriving from overvoltage and other possible issues resulting from the connection to the DGS power supply and the serial communication network. Moreover it provides the operations executed via handheld Service Tool. The display of the hand-held Service Tool and the MODBUS interface for integration with Building Management Systems is used as interface for operation, commissioning and calibration of the DGS gas detection unit.

2. Introduction

3. Installation and

maintenance

3.1 Technician use only!

For what concerns display devices, this user guide contains the maximum possible functionality.

Depending on the DGS type some features described here are not applicable and therefore the menu items may be hidden.

Some special features are available via the hand-held Service Tool interface only (not via MODBUS). This includes the calibration routine and certain properties of the sensor head.

This unit must be installed by a suitably qualiﬁed technician who will install this unit in accordance with these instructions and the standards set down in their particular industry/country.

Suitably qualiﬁed operators of the unit should be aware of the regulations and standards set down by their industry/country for the operation of this unit.

These notes are only intended as a guide, and the manufacturer bears no responsibility for the installation or operation of this unit.

Please observe that DGS works as a safety device securing a reaction to a detected high gas concentration. If a leakage occurs, the DGS will provide alarm functions, but it will not solve or take care of the leakage root cause itself.

Failure to install and operate the unit in accordance with these instructions and with industry guidelines may cause serious injury including death, and the manufacturer will not be held responsible in this regard.

It is the installer’s responsibility to adequately ensure that the equipment is installed correctly and set up according to the environment and the application in which the products are being used.

3.2 Regular Test

3.3 Location

To maintain product performance and comply with the local requirements, the DGS must be tested regularly. DGSs are provided with a test button that may be activated to validate the alarm reactions. Additionally, the sensors must be tested by either bump test or calibration. Danfoss recommends the following minimum calibration intervals: DGS-IR: 60 months DGS-SC: 12 months DGS-PE: 6 months

For all gases heavier than air, Danfoss recommends placing the sensor head app. 30 cm (12”) above the ﬂoor and, if possible, in the air ﬂow. All gases measured with these DGS sensors are heavier than air: HFC grp 1, HFC grp 2, HFC grp 3, CO and propane.

For further details on Test and Location please see the Danfoss Application Guide: “Gas detection in refrigeration systems”.

With DGS-IR it is recommended to do an annual bump test in years without calibration. Check local regulations on calibration or testing requirements. For propane: after exposure to a substantial gas leak, the sensor should be checked by bump test or calibration and replaced if necessary.

Danfoss

User Guide | Danfoss Gas sensor, type DGS

3.4 Dimensions and

appearance

Fig. 1

3.5 Cable gland opening

3.6 Board pinout

Fig. 2

Hole punching for cable gland:

1. Select the location for the safest

cable entry

2. Use a sharp screwdriver and a

small hammer

3. Place the screwdriver and

hammer with precision while moving the screwdriver within a small area until the plastic is penetrated.

Fig. 3

open: 0-20mA closed: 0-10V

JP5

not used

LED Yellow/Green/Red

GND

AO_01

DI_01

S&H supply

Continue precision punching with small movements until the round piece can be pulled out with your ﬁngers.

Remove potential burrs and secure ﬂat surfaces.

Install the cable gland according to the enclosed guide.

WARNING: be very careful not to damage the internal

board components with the screwdriver.

Rel. 3

Ackn.-/Test button

(critical)

Rel. 1

(warning)

Danfoss

80Z790.1

BMODBUS

A+

24 V AC/D +

148H126_01-2018

JP4

Sensor 2

Tool

Sensor 1

JP3 JP2 JP1

not used

B&L

open: 19200 Baud closed: 38400 Baud

Note: For what concern the power supply, please refer to chapter 3.10 Power Conditions and Shielding Conceptions.

A Class II power supply is recommended

4 | BC291049702513en-000201 © Danfoss | Climate Solutions | 2022.01

User Guide | Danfoss Gas sensor, type DGS

Status LED / B&L:

GREEN is power on.

– ﬂashing if maintenance needed

YELLOW is an indicator of Error.

– the sensor head is disconnected or not the

expected type

– AO conﬁgured as 0 – 20 mA, but no current

is running

– ﬂashing when sensor is in special mode (e.g.

when changing parameters with the Service Tool)

– Supply voltage out of range

RED ﬂashing: is an indication of alarm due to gas concentration level. The Buzzer & Light behaves identical to the status LED.

Ackn. / Test button / DI_01:

TEST: The button must be pressed for 8 sec.

– Critical and warning alarm is simulated and

AO goes to max. (10 V/20 mA), stops on release.

ACKN: If pressed during critical alarm, as default* the relays and Buzzer go out of alarm condition and back on after 5 minutes if the alarm situation is still active.

* the duration and whether to include the relay status with this function or not is user deﬁned. DI_01 (terminals 1 and 2) is a dry-contact (potential-free) behaving identically to the Ackn./Test button.

DC supply for external Strobe & Horn

Whether the DGS is powered by 24 V DC or 24 V AC, a 24 V DC power supply (max. 50 mA) is available between terminals 1 and 5 on connector x1.

Jumpers

* JP4 open → 19200 Baud JP4 closed → 38400 Baud (default)

* JP5 open → AO 0 – 20 mA JP5 closed → AO 0 – 10 V (default)

Note: the DGS must be power cycled before any change to JP4 takes eﬀect.

Analog Output:

If the analog output AO_01 is used (terminals 4 and 5) then you need the same ground potential for the AO and the connected device.

Note: JP1, JP2 and JP3 are not used.

3.7 Installation instructions

The DGS is available with one or two sensors and B&L (Buzzer and Light) as option (see ﬁg. 1). For sensors that can be poisoned by e.g. silicones like all semiconductor and catalytic bead sensors, it is imperative to only remove the protective cap after all silicones are dry, and then energize the device. The sensor protection cap must be removed before taking the DGS into operation

Mounting and wiring

To wall mount the DGS, unscrew the lid by releasing the four plastic screws in each corner and remove the lid. Mount the DGS base to the wall by ﬁtting screws through the holes which the lid screws were fastened by. Complete the mounting by re-applying the lid and fastening the screws. The sensor head must always be mounted so that it points downwards. The DGS-IR sensor head is sensitive to shock – special attention should be paid to protect the sensor head from shocks during installation and operation. Observe the recommended placing of the sensor head as stated on page 1. Extra cable glands are added by following the instruction in ﬁg. 2. The exact position of the terminals for the sensors, alarm relays, digital input and analogue output is shown in the connection diagrams (see ﬁg. 3). The technical requirements and regulations for wiring, electrical security, as well as project speciﬁc and environmental requirements and regulations must be met.

Conﬁguration

For convenient commissioning, the DGS is preconﬁgured and parameterized with factory-set defaults. See Menu Survey on page 5.

Jumpers are used to change the analogue output type and the MODBUS baud rate. See ﬁg. 3. For DGS with Buzzer & Light, alarm actions are given according to following table below.

System integration

To integrate the DGS with a Danfoss system manager or general BMS system, set the MODBUS address using the DGS Service Tool, using password "1234" when prompted. See the DGS User Guide for details on operating the DGS Service Tool. The Baud Rate is adjusted by jumper JP4. As default, the setting is 38.4k Baud. For integration with AK-SM 720/350 change the setting to 19.2k Baud. For more information about data communication see Danfoss document RC8AC--

Sensor replacement

The sensor is connected to the DGS via a plug connection enabling simple sensor exchange instead of an on-site calibration. The internal replacement routine recognizes the exchanging process and the exchanged sensor and re-starts the measurement mode automatically. The internal replacement routine also examines the sensor for actual type of gas and actual measuring range. If the data does not match the existing conﬁguration, the built-in status LED indicates an error. If everything is OK the LED will light up green.

As an alternative, the on-site calibration via the DGS Service Tool can be performed with the integrated, user friendly calibration routine.

See the DGS User Guide for details on operating the DGS Service Tool.

User Guide | Danfoss Gas sensor, type DGS

Action Reaction

Loss of power to DGS OFF OFF X (closed) Gas signal < warning alarm threshold Gas signal > warning alarm threshold Gas signal > critical alarm threshold Gas signal ≥ critical alarm threshold, but ackn. button pressed No alarm, no fault OFF GREEN No fault, but maintenance due OFF GREEN Slow

Sensor communication error OFF YELLOW DGS in special mode OFF YELLOW ﬂashing

Alarm thresholds can have the same value, therefore both the relays and the Buzzer and Light can be triggered simultaneously. The alarm thresholds have a hysteresis of app. 5% * whether to include the relay status with the acknowledge function or not is user deﬁned. ** If the DGS has two sensors and the "Room Mode" is conﬁgured to "2 rooms", then relay 1 acts as a critical

relay for sensor 1 and relay 3 acts as a critical relay for sensor 2. Both relays are SPDT NC. The Buzzer and Light operation is independent of the "Room Mode" setting.

Buzzer

OFF GREEN

OFF RED Slow ﬂashing X (closed)

ON RED Fast ﬂashing X (closed) X (closed)

OFF (ON after delay)

3.8 Installation Test As DGS is a digital device with self-monitoring, all internal errors are visible via the LED and MODBUS alarm messages. All other error sources often have their origins in other parts of the installation. For fast and comfortable installation test we recommend proceeding as follows.

Optical Check

Right cable type used. Correct mounting height according to deﬁnition in the section about mounting. LED status – see DGS trouble shooting.

Reaction Light

RED Fast ﬂashing X (closed)* (open)*

ﬂashing

Warning relay 1** SPDT NO (Normally Open)

Critical relay 3** SPDT NC (Normally closed)

In doing so, the set alarm thresholds are exceeded, and all output functions are activated. It is necessary to check if the connected output functions are working correctly (e.g. the horn sounds, the fan switches on, devices shut down). By pressing the push-button on the horn, the horn acknowledgement must be checked. After removal of the reference gas, all outputs must automatically return to their initial position. Other than the trip testing, it is also possible to perform a functional test by means of calibration. For further information, please refer to the User Guide.

Functional test (for initial operation and maintenance)

Functional test is done by pressing the test button for more than 8 seconds and observing that all connected outputs (Buzzer, LED, Relay connected devices) are working properly. After deactivation all outputs must automatically return to their initial position.

Zero-point test (if prescribed by local regulations)

Zero-point test with fresh outdoor air. A potential zero oﬀset can be read out by use of the Service Tool.

Trip test with reference gas (if prescribed by local regulations)

The sensor is gassed with reference gas (for this you need a gas bottle with pressure regulator and a calibration adapter).

Comparing sensor gas type with DGS speciﬁcation

The replacement sensor speciﬁcation must match the DGS speciﬁcation.

The DGS software automatically reads the speciﬁcation of the connected sensor and compares with the DGS speciﬁcation.

This feature increases the user and operating security.

New sensors are always delivered factorycalibrated by Danfoss. This is documented by the calibration label indicating date and calibration gas. A re-calibration is not necessary during commissioning if the device is still in its original packaging (including air-tight protection by the red protective cap) and if the calibration certiﬁcate has not expired

6 | BC291049702513en-000201 © Danfoss | Climate Solutions | 2022.01

oss

80Z875

Busmaster

User Guide | Danfoss Gas sensor, type DGS

3.9 Troubleshooting

3.10 Power Conditions and

Shielding Conceptions

Symptom: Possible cause(s):

LED oﬀ • Check power supply. Check wiring.

• DGS MODBUS was possibly damaged in transit. Check by installing another DGS to conﬁrm the fault.

Green ﬂashing • The sensor calibration interval has been exceeded or the sensor has reached the

end of life. Carry out calibration routine or replace with a new factory calibrated sensor.

Yellow • AO conﬁgured but not connected (only 0 – 20 mA output). Check wiring.

• Sensor type does not match DGS speciﬁcation. Check gas type and measuring range.

• Sensor may be disconnected from printed circuit board. Check to see if the sensor is properly connected.

• The sensor has been damaged and needs to be exchanged. Order replacement sensor from Danfoss.

• Supply voltage out of range. Check power supply.

Yellow ﬂashing • The DGS is set to service mode from the hand-held Service Tool. Change setting

or await time-out within 15 minutes.

Alarms in the absence of a leak

The zero-measurement drifts

• If you experience alarms in the absence of a leak, try setting an alarm delay.

• Perform a bump test to ensure proper operation.

The DGS-SC sensor technology is sensitive to the environment (temperature, moist, cleaning agents, gases from trucks, etc). All ppm measurements below 75 ppm should be disregarded, i.e. no zero-adjustment made.

Standalone DGS without Modbus network communication

Shield/screen is not required for standalone DGS with no connection to a RS-485 communication line. However, it can be done as described in the next paragraph (Fig. 4).

DGS with Modbus network communication in combination with other devices powered by the same power supply

It is strongly recommended to use direct current power supply when:

• more than 5 DGS units are powered by the same power supply

• the bus cable length is longer than 50 m for those powered units

It is moreover recommended to use class 2 power supply (see AK-PS 075)

Make sure to not interrupt the shield when connecting A and B to the DGS (see Fig. 4).

–

A+B

Fig. 4: Loop trough

Shield

Shld

DGS 1 #adr 10 A B Gnd

Danfoss Modbus

device

Fig. 5: Wiring diagram for system with one power supply

Danf

AK-PS 075 power supply

DGS 2 #adr 11 A B Gnd

1 KΩ

DGS n #adr xx A B Gnd

–

Input 230 V

230 V

Danfoss

80Z876

Ground potential diﬀerence between nodes of the RS485 network might aﬀect the communication. It is advised to connect a 1 KΩ 5% ¼ W resistor between the shield and the ground (X4.2) of any unit or group of units connected to the same power supply (Fig. 5). Please refer to Literature No. AP363940176099.

Busmaster

User Guide | Danfoss Gas sensor, type DGS

DGS with Modbus network communication in combination with other devices powered by more than one power supply

It is strongly recommended to use direct current power supply when:

• more than 5 DGS units are powered by the same power supply

• the bus cable length is longer than 50 m for those powered units It is moreover recommended to use class 2 power supply (see AK-PS 075)

Make sure to not interrupt the shield when connecting A and B to the DGS (see Fig. 4).

1 KΩ

Shield

DGS 1 #adr n1 A B Gnd

Shield

DGS 1 #adr n11 A B Gnd

AK-PS 075 power supply

DGS 2 #adr n2 A B Gnd

DGS 2 #adr n12 A B Gnd

DGS n #adr nx A B Gnd

DGS n #adr ny A B Gnd

–

AK-PS 075 power supply

–

230 V

Danfoss

Modbus

device AK-SM

Shld

Busslave

230 V

Danfoss

Modbus

device AK-CC

Shld

Fig. 6: Wiring diagram for system with multiple power supplies

Power supply and voltage alarm

The DGS device goes into voltage alarm when voltage exceeds certain limits. The lower limit is 16 V. The upper limit is 28 V, if DGS software version is lower than 1.2 or 33.3 V in all other cases. When in the DGS the voltage alarm is active, in the System Manager the “Alarm inhibited” is raised.

Danfoss

80Z878

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