Next Generation Gas Detection
“
Specifications:
- Product: Danfoss Gas Detection Modbus communication
- Communication Interface: Modbus RTU
- Controller Address: Slave ID default = 1 (changeable in Display
Parameters) - Baud Rate: 19,200 baud
- Data Format: 1 start bit, 8 data bits, 1 stop bit, even
parity
Product Usage Instructions:
1. Modbus Function 03 – Read Holding Registers
This function is used to receive data from the Danfoss gas
detection controller. The following data blocks are available:
- Current value of digital sensors (addresses 1 to 96d)
- Current value of analog sensors (addresses 1 to 32d)
- Average value of digital sensors
- Average value of analog sensors
- Measuring range of digital sensors
- Measuring range of analog sensors
The measured values are represented in Integer format with
different factors depending on the measuring range.
Representation of measured values:
- 1 – 9: Factor 1000
- 10 – 99: Factor 100
- 100 – 999: Factor 10
- From 1000 onwards: Factor 1
If the value is below -16385, it is considered an error message
and should be interpreted as a hexadecimal value.
FAQ:
Q: Can the Controller Address (Slave ID) be changed?
A: Yes, the Controller Address can be changed in the Display
Parameters.
Q: What is the standard Baud Rate for communication?
A: The standard Baud Rate is set at 19,200 baud and is not
changeable.
Q: What is the standard protocol for the gas controller X
bus?
A: The standard protocol is Modbus RTU.
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User Guide
Danfoss Gas Detection Modbus communication
GDIR.danfoss.com
User Guide | Danfoss Gas Detection – Modbus communication
Contents
Page Part 1 Modbus communication from the Danfoss Gas Detection Controller Serial Modbus Interface at the X BUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 1. Modbus Function 03. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
1.1 Current value of digital sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 1.2 Current value of analog sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 1.3 Average value of digital sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 1.4 Average value of analog sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 1.5 Measuring range of digital sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 1.6 Measuring range of analog sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 1.7 Display of the alarms and the respective latching bits of digital sensors . . . . . . . . . . . . . . . . . . . . . . .5 1.8 Display of the alarms and the respective latching bits of analog sensors. . . . . . . . . . . . . . . . . . . . . . .5 1.9 Relay status of the signal relays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 1.10 Relay status of the alarm relays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 1.11 Gas detection controller Watch Outputs (WI), MODBUS addresses 50 to 57. . . . . . . . . . . . . . . . . . .6 1.12 Data block: Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2. Modbus-Function 05 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 2.1 Acknowledgement of latching mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 2.2 Acknowledgement of horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 2.3 Activation of the single Watch Output via Modbus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 3. Modbus Function 06. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 4. Modbus-Function 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 5. Modbus Function 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Part 2 Modbus Communication guide for the Danfoss Gas Detection Units (Basic, Premium and Heavy Duty Serial Modbus Interface at the ModBUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 1. Modbus Function 03. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
1.1 Measured Value Query (compressed form) from version 1.0. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 1.2 Measured Values & Status Query (uncompressed form) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.3 Operating data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2. Modbus Function 06. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3. Modbus Function 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4. Notes and General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.1 Intended Product Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.2 Installer’s Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.3 Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
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User Guide | Danfoss Gas Detection – Modbus communication
Part 1 – Modbus communication from the Danfoss Gas Detection Controller
Serial Modbus Interface at the X BUS
Please note: Using standard Modbus Protocoll will not include the dedicated gas detection SIL safety communication Protocoll. Safety aspect of SIL1/SIL2 is therefore not related to this kind of bus interface.
This functionality is available from display version 1.00.06 or higher.
The standard protocol for an additional serial port of the gas controller X bus is ModBus RTU.
Definition of communication The gas controller operates at the interface X bus only as MODBUS slave. Controller Address = Slave ID default = 1, (can be changed in Display Parameters).
Baud rate 19,200 baud (not changeable) 1 start bit, 8 data bits 1 stop bit, even parity
Address = Start address see descriptions below Length = Number of Datawords see descriptions below.
1. Modbus Function 03
Read Holding Registers (reading of holding registers) are used to receive data from the Danfoss gas detection controller. There are 9 data blocks.
1.1
Current value of digital sensors sensor
Current value of digital sensors addresses 1 to 96d.
1.2
Current value of analog sensors sensor
Current value of analog sensors addresses 1 to 32d.
Available in MODBUS Start address.. 1001d to 1096d.
Available in MODBUS Start address.. 2001d to 2032d.
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Representation of measured values: The measured values are shown in the Integer format with a factor of 1, 10, 100 or 1000. The factor depends on the respective measuring range and is used as follows:
Range
Factor
1 -9
1000
10-99
100
100-999
10
From 1000 on
1
If the value is below -16385, it is an error message and should be considered as a hexadecimal value in order to break the errors down.
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1.3 Average value of digital sensors
Average value of digital sensors sensor addr.. 1 to 96d. Available in MODBUS Start address.. 3001d to 3096d.
1.4 Average value of analog sensors
Average value of analog sensors- sensor addr.. 1 to 32d. Available in MODBUS Start address.. 4001d to 4032d.
1.5 Measuring range of digital sensors
1.6 Measuring range of analog sensors
Measuring range of digital sensors – sensor addr. 1 to 96d. Available in MODBUS Start address.. 5001d to 5096d.
Measuring range of analog sensors – sensor addr.. 1 to 32d. Available in MODBUS Start address.. 6001d to 6032d
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User Guide | Danfoss Gas Detection – Modbus communication
1.7 Display of the alarms and the respective latching bits of digital sensors
1.8 Display of the alarms and the respective latching bits of analog sensors
Display of the local alarms generated by the gas detection controller as well as of the respective latching bits of digital sensors – sensor addresses 1 to 96d. Available in MODBUS Start address 1201d to 1296d.
Display of the local alarms generated by the gas detection controller as well as of the respective latching bits of analog sensors – sensor addresses 1 to 32d. Available in MODBUS Start address 2201d to 2232d
.
Here, the representation in the hexadecimal form is easier to read because the data are transmitted in the following form:
0xFFFF = 0x 0b
F 1111 Local latching
F 1111 Controller latching
There are four status bits for the four alarm stages each. 1 = alarm or latching active 0 = alarm or latching not active
The above example: There are two local alarms at DP1, with the second being in latching mode. The first alarm generated by the gas detection controller is present at DP4. The first alarm generated by the gas detection controller is present at AP5.
F 1111 Local alarms
F 1111 Controller alarms
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User Guide | Danfoss Gas Detection – Modbus communication
1.9 Relay status of the signal relays
Relay status of the signal relays signal relay address 1 to 96d. Available in MODBUS Start address…. 7001d to 7096d
1.10 Relay status of the alarm relays
Relay status of the alarm relays alarm relay address 1 to 32d. Available in MODBUS Start address…. 8001d to 8032d
The relay status of the controller`s fault message relay is in register 8000d.
1.11 Gas detection controller Watch Outputs (WI), MODBUS addresses 50 to 57
In register 50d, all watch outputs are shown as a byte as used for evaluation in the gas detection controller.
In the Start address 51d 57d the individual bit values are available as Integer values.
0d = No output set 1d = Switch on by clock 256d or 0x0100h = Switch on by Modbus 257d or 0x0101h = Switch on by Modbus and clock
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User Guide | Danfoss Gas Detection – Modbus communication
1.12 Data block: Output
Start address 0d: My own slave MODBUS address at the X Bus
Address 1d:
Relay information bits of the first module (Controller Module) Relay 1 is bit 0 to relay 4 is bit 3
Address 2d:
Relay information bits of the extension module address_1 Relay 5 is bit 0 to relay 8 is bit 3
Address 3d:
Relay information bits of the extension module address_2 Relay 9 is bit 0 to relay 12 is bit 3
Address 4d:
Relay information bits of the extension module address 3 Relay 13 is bit 0 to relay 16 is bit 3
Address 5d:
Relay information bits of the extension module address_4 Relay 17 is bit 0 to relay 20 is bit 3
Address 6d:
Relay information bits of the extension module address_5 Relay 21 is bit 0 to relay 24 is bit 3
Address 7d:
Relay information bits of the extension module address_6 Relay 25 is bit 0 to relay 28 is bit 3
Address 8d:
Relay information bits of the extension module address_7 Relay 29 is bit 0 to relay 32 is bit 3
The addresses 9d to 24d stand for hardware analog output 1 to analog output 16.
The definition of the values is done between 0 and 10000d ( 0 = 4mA Output; 10.000d = 20mA Output= full scale value of the sensor, 65535 mark as not used)..
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User Guide | Danfoss Gas Detection – Modbus communication
2. Modbus-Function 05
Write Single Coil (writing of single states ON/OFF) is used to acknowledge the latching mode or the horns as well as to set clock outputs individually.
2.1 Acknowledgement of latching mode
For this purpose, the command 05 is sent to the address of the gas detection controller with the indication of the respective register from 1.7 or 1.8 Display of the alarms and the respective latching bits
The acknowledgment only takes place when the value ON(0xFF00) has been sent.
2.2 Acknowledgement of horn
For this purpose, command 05 is sent to the address of gas detection controller and register 7000d.
The acknowledgment only takes place when the value ON(0xFF00) has been sent.
2.3 Activation of the single Watch Output via Modbus
For this purpose, the command 05 is sent to the address of the g as detection controller with the indication of the respective register from 1.11 Display of the Watch Outputs witch register 50 not being allowed.
3. Modbus Function 06
Write Single Registers (writing of single registers) is used to write on individual registers in the gas detection controller.
Currently, it is only possible to write on the own slave address.
Modbus address 0 (see 1.12)
4. Modbus-Function 15
Write Multiple Coil (writing multiple states OFF/ ON) is used to set all watch outputs at once. The command must be sent to gas detection controller address with the indication of register 50d with a maximum length of 7 bits.
5. Modbus Function 16
Write Multiple Registers (writing of several registers) is used to write on several registers in the gas detection controller.
Currently, it is only possible to write on the own slave address.
Modbus address 0 (see 1.12)
All other parameter changes are not permitted for safety reasons; therefore, the data direction is clearly defined from the warning system to the open MODBUS side. Retroaction is not possible.
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User Guide | Danfoss Gas Detection – Modbus communication
Part 2 – Modbus Communication guide for the Danfoss Gas Detection Units (Basic, Premium and Heavy Duty)
Serial Modbus Interface at the ModBUS
The standard protocol for an additional serial port of the gas controller Modbus is ModBus RTU.
Definition of communication:
The gas detection unit (Basic, Premium or Heavy Duty) operates at the RS 485 interface (Bus A, Bus B Terminals) only as MODBUS slave.
Parameter for communication:
Baud rate 19,200 baud 1 start bit, 8 data bits 1 stop bit, even parity
Periodic polling rate:
> 100 ms per address. For polling rates < 550 ms it is essential to insert at least one pause of > 550 ms per polling cycle.
Fig 1: Settings for Modbus query
1. Modbus Function 03
Read Holding Registers (reading of holding registers) are used to receive data from the Gas Detection Controller system.
1.1 Measured Value Query (compressed form) from version 1.0
It is possible to query the initial address 0 with a length of exactly 10 information (words).
Example here SlaveID = Slave address = 3
Fig 1.1a: Query values
Basic and Premium units:
In the ModBus query, the values are as follows:
offs Register Addresses 0 – 9 0 Current Value Sensor 1 1 Average Sensor 1 2 Current Value Sensor 2 3 Average Sensor 2 4 Current Value Sensor 3 5 Average Sensor 3 6 Type + Range Sensor 1 7 Type + Range Sensor 2 8 Type + Range Sensor 3 9 Current Temperature °C
Table 1.1b: Registered values
Fig. 1.1c: Window section from Modbus query
Heav Duty units:
In the case of the Heavy Duty ModBus query, only the values of the first input are occupied, all others are shown with 0:
Dynamic resolution for the gas information is used, that means that if the measuring range < 10, then the gas value is multiplied with 1000, if the measuring range < 100 & >=10, then the gas value is multiplied with 100, if the measuring range < 1000 & >=100, then the gas value is multiplied with 10, if the measuring range >= 1000, then the gas value is multiplied with 1. So in all cases a resolution of 1000 can be guaranteed.
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User Guide | Danfoss Gas Detection – Modbus communication
1.2 Measured Values & Status Query (uncompressed form)
Two query options are available here:
A: Query all information via the base address of the device: Fixed register (start) address 40d (28h) with variable length 1 to 48 d information (words) Example here Slave ID = Slave Address = 3 (The other addresses 4 and 5 are not necessary because all information is transferred in a block)
B: Only query the corresponding sensor via the different individual addresses: The start addresses are defined according to Table 1.2c, with a fixed length of 12 values
Fig.1.2a: Modbus query parameters for version A
The data are arranged in the following order:
offs Sensor 1 Device Base Address Register Addr. 40-51 Device Base Address Register Addr. 40-51
0 gastype_1 1 range_1 2 divisor_1 3 current_value_1 4 average_value_1 5 error_1 6 alarm_1 7 di+relay 8 threshold_1a 9 threshold_1b 10 threshold_1c 11 threshold_1d Table 1.2c: Arrangement of information
Fig. 1.2b: Sensor 1 – 3 Modbus query parameters for version B
Sensor 2 Device Base Address Register Addr. 52-63 Device Base Address +1 Register Addr. 40-51 gastype_2 range_2 divisor_2 current_value _2 average_value _2 error_2 alarm_2 di+relay threshold_2a threshold_2b threshold_2c threshold_2d
Sensor 3 Device Base Address Register Addr. 64-75 Device Base Address +2 Register Addr. 40-51 gastype_3 range_3 divisor_3 current_value _3 average_value _3 error_3 alarm_3 di+relay threshold_3a threshold_3b threshold_3c threshold_3d
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User Guide | Danfoss Gas Detection – Modbus communication
1.2 Measured Values & Status Query (uncompressed form)
Offs Sensor 1 Sensor 1 Register addr 40-51 Sensor 1 Register addr. 40-51
0 gastype_1 1 range_1 2 divisor_1 3 current_value_1 4 average_value_1 5 error_1 6 alarm_1 7 di+relay 8 threshold_1a 9 threshold_1b 10 threshold_1c 11 threshold_1d
Table 1.2e: Value example
Values
1302 25 100 314 314 0 0 12
1301 1402 1503 1604
Sensor 2 Sensor 2 Register addr 52-63 Sensor 2 Register addr. 52-63 gastype_2 range_2 divisor_2 current_value_2 average_value_2 error_2 alarm_2 di+relay threshold_2a threshold_2b threshold_2c threshold_2d
Values
1177 100 10 306 306
0 0 12 501 602 703 803
Sensor 3 Sensor 3 Register addr. 64-75 Sensor 3 Register addr. 64-75 gastype_3 range_3 divisor_3 current_value_3 average_value_3 error_3 alarm_3 di+relay threshold_3a threshold_3b threshold_3c threshold_3d
Values
1277 2500
0 1331 1331
0 112 12 2400 3600 1600 80
Register description of measuring values for 1.2 A and 1.2 B
Addresses offs Parameter Name
Meaning
40,52,64 0 Gastype_x ui16
Gas type code of sensor 1, 2, 3 see table
41,53,65 1 Range_x ui16
Measuring range of sensor 1, 2, 3 (integer without translation)
42,54,66 2 divisor_x ui16
Divisor factor of sensor 1, 2, 3 (e.g. register value = 10 -> all measured values and alarm thresholds have to be divided by 10.
43,55,67 3 cur_val_x signed i16
Current value of sensor 1, 2, 3: Value presentation as integer (is multiplied with the divisor factor, therefore the actual gas value has to be divided by the divisor factor)
44,56,68 4 average_val_x signed i16 Average value of sensor 1, 2, 3: Value presentation as integer (is multiplied with the divisor factor, therefore the actual gas value has to be divided by the divisor factor)
45,57,69 5 error_x ui16
Error information, binary coded, see table 1.3f error codes
46,58,70 6 alarm_x ui16
Alarm status bits of sensor 1, 2, 3, binary coded, Alarm1(bit4) Alarm4 (bit7), SBH (Self Hold Bit) information bits Alarm1(bit12)- Alarm4(bit15)
47,59,71 7 di+rel_x uii16
Alarm status bits of relay 1(bit0) 5(bit4), and digital input states 1(bit8)-2 (bit9)
48,60,72 8 threshold_x y ui16
Threshold 1 of sensor 1, 2, 3, Value presentation as integer (is multiplied with the divisor factor, therefore the actual gas value has to be divided by the divisor factor)
49,61,73 9 threshold_x y ui16
Threshold 2 of sensor 1, 2, 3, Value presentation as integer (is multiplied with the divisor factor, therefore the actual gas value has to be divided by the divisor factor)
50,62,74 10 threshold_x y ui16
Threshold3 of sensor 1, 2, 3, Value presentation as integer (is multiplied with the divisor factor, therefore the actual gas value has to be divided by the divisor factor)
51,63,75 11 threshold_x y ui16
Threshold 4 of sensor 1, 2, 3, Value presentation as integer (is multiplied with the divisor factor, therefore the actual gas value has to be divided by the divisor factor)
Table 1.2f: Register description of measuring values for 1.2 A and 1.2 B
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User Guide | Danfoss Gas Detection – Modbus communication
1.3 Operating data
Two query options are available here:
A: Query all information via the base address of the
device:
Fixed register (start) address 200d (28h) with
length 1 to 48 d information (words)
Example here: Slave ID = Slave Address = 3
(The other addresses 4 and 5 are not used here.)
Start Address always 200d.
Number of sensors: 1 2
Lengths:
18 36
B: Only query the corresponding sensor via the different individual addresses: The start addresses are defined according to Table 1.2c, with a fixed length of 18 values
Fig.1.3a: Modbus query parameters Version A
Fig. 1.3b: Sensor 1 – 3 Modbus operating data Modbus query parameters Version B
Arrangement of the data
Table 1.3c: Arrangement of the data
offs Sensor 1 (all devices) Device base address Start address 200-217d Device base address Start address 200-217d
0 prod_dd_mm_1 1 prod_year_1 2 serialnr_1 3 unit_type_1 4 operating_days_1 5 days_till_calib_1 6 opday_last_calib_1 7 calib_interv_1 8 days_last_calib_1 9 sensibility_1 10 cal_nr_1 11 tool_type_1 12 tool_nr_1 13 gas_conz_1 14 max_gas_val_1 15 temp_min_1 16 temp_max_1 17 free
Sensor 2 (Only Premium) Device base address Start address 218-235d Device base address +1 Start address 200-217d prod_dd_mm_1 prod_year_2 serialnr_2 unit_type_2 operating_days_2 days_till_calib_2 opday_last_calib_2 calib_interv_2 days_last_calib_2 sensibility_2 cal_nr_2 tool_type_2 tool_nr_2 gas_conz_2 max_gas_val_2 temp_min_2 temp_max_2 free
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User Guide | Danfoss Gas Detection – Modbus communication
1.3 Operating data (Continued)
Register description of operating data acc. to 1.3 A and 1.3 B
Adresses offset bildname
Meaning
200,218,236 0
prod_dd_mm ui16
= Device manufacturing day + month, hex coded e.g. 14.3: 0x0E03h = 14 (day) 3 (month)(year)
201,219,237 1
prod_year ui16
Device manufacturing year e.g. 0x07E2h = 2018d
202,220,238 2
Serialnr ui16
Manufacturer’s device serial number
203,221,239 3
unit_type ui16
Device type: 1 = Sensor Head 2 = Basic, Premium unit 3 = Gas Detection Controller
204,222,240 4
operating_days ui16
Number of current operating days
205,223,241 5
days_till_calib signed i16
Number of remaining operating days until next maintenance negative values stand for exceeded maintenance time limit
206,224,242 6
opday_last_calib Operating days until last calibration ui16
207,225,243 7
calib_interv ui16
Maintenance interval in days
208,226,244 8
days_last_calib ui16
Number of remaining operating days of the previous maintenance period until next maintenance
209,227,245 9
Sensibility ui16
Current sensor sensitivity in % (100% = new sensor)
210,228,246 10
cal_nr b ui16
Number of already performed calibrations
211,229,247 11
tool_type ui16
Manufacturer’s serial number of calibration tool
212,230,248 12
tool_nr ui16
Manufacturer’s ID number of calibration tool
213,231,249 13
gas_conz ui16
Average value of the gas concentration measured at the sensor over the time
214,232,250 14
max_gas_val signed i16
Highest gas concentration measured on the sensor
215,233,251 15
temp_min signed i16
Lowest temperature meassured on the sensor
216,234,252 16
temp_max signed i16
Highest temperature measured on the sensor
217,235,253 17 ui16
Not used
Table 1.3d: Register description of operating data acc. to 1.3 A and 1.3 B
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User Guide | Danfoss Gas Detection – Modbus communication
1.3 Operating data (Continued)
Gas types and units
Gas Code
Type
1286
E-1125
1268
EXT
1269
EXT
1270
EXT
1271
EXT
1272
EXT
1273
EXT
1275
EXT
1276
EXT
1179
P-3408
1177
P-3480
1266
S164
1227
S-2077-01
1227
S-2077-02
1227
S-2077-03
1227
S-2077-04
1227
S-2077-05
1227
S-2077-06
1227
S-2077-07
1227
S-2077-08
1227
S-2077-09
1227
S-2077-10
1227
S-2077-11
1230
S-2080-01
1230
S-2080-02
1230
S-2080-03
1230
S-2080-04
1230
S-2080-05
1230
S-2080-06
1230
S-2080-07
1230
S-2080-08
1233
S-2125
Table 1.3e: Table of gas types and units
Gas Type Ammonia TempC TempF Humidity Pressure TOX Comb. External Digital Ammonia Propane Carbon dioxide R134a R407a R416a R417a R422A R422d R427A R437A R438A R449A R407f R125 R32 R404a R407c R410a R434A R507A R448A R717
Formula NH3 TempC TempF Hum. Press TOX Comb
NH3 C3H8 CO2 C2H2F4
C2HF5 CH2F2
NH3
Unit ppm C F %rH mbar ppm %LEL % % % LEL % LEL % Vol ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm
Error codes occurring in the Modbus query are the same as documented in the user guide “Controller unit and Expansion module”. They are bit coded and may occur combined.
,,DP 0X Sensor Element” ,,DP 0X ADC Error” ,,DP 0X Voltage” ,,DP 0X CPU Error” ,,DP 0x EE Error” ,,DP 0X I/O Error ” ,,DP 0X Overtemp.” ,,DP 0X Overrange” ,,DP 0X Underrange” ,,SB 0X Error” ,,DP 0X Error” ,,EP_06 0X Error” ,,Maintenance” ,,USV Error” ,,Power Failure” ,,Horn Error” ,,Warning Sign Error” ,,XXX FC: 0xXXXX” Table 1.3f: Error Codes
0x8001h (32769d) Sensor element in the sensor head – error 0x8002h (32770d) Monitoring of the amplifier and AD converter – error 0x8004h (32772d) Monitoring of the sensor and/or process power supply – error 0x8008h (32776d) Monitoring of the processor function error 0x8010h (32784d) Monitoring of the data storage reports an error. 0x8020h (32800d) Power ON / monitoring of the in/outputs of processor – error 0x8040h (32832d) Ambien temperature too high 0x8200h (33280d) Signal of sensor element at the sensor head is over range. 0x8100h (33024d) Signal of sensor element at the sensor head is under range. 0x9000h (36864d) Communication error from central unit to SB 0X 0xB000h (45056d) Communication error of SB to DP 0X sensor 0x9000h (36864d) Communication error to EP_06 0X module 0x0080h System maintenance is due. 0x8001h (32769d) USV doesn’t work properly, can only be signalled by the GC. 0x8004h (32772d) can only be signalled by the GC. 0xA000h (40960d) can only be signalled by the GC/EP with hardware option. 0x9000h (36864d) can only be signalled by the GC/EP with hardware option. Occurs, if there are several errors from one measuring point.
14 | BC283429059843en-000301
© Danfoss | DCS (ms) | 2020.09
User Guide | Danfoss Gas Detection – Modbus communication
2. Modbus Function 06
Write Single Registers (writing of single registers) is used to write on individual registers in the gas detection controller.
Currently, it is NOT possible to write any information.
3. Modbus Function 16
Write Multiple Registers (writing of several registers) is used to write on several registers in the gas detection controller.
This command is used to change the device addresses.
Attention: They must be known in advance, and only one device with the same address may be on the bus, otherwise all devices will be readdressed. This example changes device address 3 to address 12 Fixed start address 333d (0x14dh) with exact length 1 (1 word).
After writing this command, the device can only be reached with the new address! All other parameter changes are not allowed for security reasons; therefore the data direction is clearly defined from the warning system side to the open MODBUS side. Retroaction is not possible.
Fig. 3.1
4. Notes and General Information
It is important to read this user manual carefully in order to understand the information and instructions. The Danfoss GD gas monitoring, control and alarm system may only be used for applications in accordance to the intended use.
The appropriate operating and maintenance instructions and recommendations must be followed.
Due to permanent product developments, Danfoss reserves the right to change specifications without notice. The information contained herein is based on data considered to be accurate. However, no guarantee or warranty is expressed or implied concerning the accuracy of these data.
4.1 Intended Product Application
The Danfoss gas detection system is designed and manufactured for controlling, for saving energy and keeping OSHA air quality in commercial buildings and manufacturing plants.
4.2 Installer’s Responsibilities
It is the installer’s responsibility to ensure that all gas detection units are installed in compliance with all national and local regulations and OSHA requirements. All installation shall be executed only by technicians familiar with proper installation techniques and with codes, standards and proper safety procedures for control installations and the latest edition of the National Electrical Code (ANSI/NFPA70).
The equipotential bonding required (also e.g. secondary potential to earth) or grounding measures must be carried out in accordance with the respective project requirements. It is important to ensure that no ground loops are formed to avoid unwanted interference in the electronic measuring equipment. It is also essential to follow strictly all instructions as provided in installation guide/user guide.
4.3 Maintenance
Danfoss recommend checking the GD gas detection system regularly. Due to regular maintenance differences in efficiency can easily be corrected. Re-calibration and replacement of parts can be realised on site by a qualified technician with the appropriate tools.
© Danfoss | DCS (ms) | 2020.09
BC283429059843en-000301 | 15
16 | BC283429059843en-000301
© Danfoss | DCS (ms) | 2020.09
Documents / Resources
![]() | Danfoss Next Generation Gas Detection [pdf] User Guide BC283429059843en-000301, Next Generation Gas Detection, Generation Gas Detection, Gas Detection |