iSMA CONTROLLI iSMA-B-MG-IP User manual
www.ismacontrolli.com
DMP260en | 1st Issue rev. 6 | 05/2022
iSMA-B-MG-IP
User Manual
iSMA-B-MG-IP User Manual
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DMP260en | 1st Issue rev. 6 | 05/2022
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Table of Contents
1 Introduction ........................................................................................................................... 4
1.1 Revision History............................................................................................................................. 5
2 Safety Rules............................................................................................................................ 6
3 Technical Specification ........................................................................................................ 7
4 Hardware Specification ....................................................................................................... 8
4.1 Dimensions .................................................................................................................................... 8
4.2 Power Supply................................................................................................................................. 8
4.3 Grounding and Shielding............................................................................................................ 8
4.4 Firmware Version and Device Type (30001) .......................................................................... 9
4.5 Uptime (30012) ............................................................................................................................. 9
4.6 Device Actions (40001)................................................................................................................ 9
4.7 Front Panel...................................................................................................................................10
4.7.1 LED Indicators .......................................................................................................................10
4.8 Default Settings...........................................................................................................................10
4.8.1 Restoring Default Settings.................................................................................................. 11
5 Modbus Gateway................................................................................................................12
5.1 Communication...........................................................................................................................13
5.1.1 RS485 Connection................................................................................................................ 13
5.2 Modbus Settings.........................................................................................................................14
5.2.1 Setting Modbus Address .................................................................................................... 14
5.2.2 Setting Baud Rate ................................................................................................................. 14
5.2.3 Setting Protocol..................................................................................................................... 15
5.3 Modbus Configuration Registers ............................................................................................15
5.3.1 Device Address (30002) ......................................................................................................15
5.3.2 Baud Rate and Protocol (30003).......................................................................................15
5.3.3 Counter of Received Messages (30004)..........................................................................16
5.3.4 Counter of Error Messages (30006)................................................................................. 16
5.3.5 Counter of Sent Messages (30008).................................................................................. 16
5.3.6 Hardware_Version (30130)................................................................................................. 16
5.3.7 MAC_Address (30131) .........................................................................................................16
5.3.8 Device Actions (40001)........................................................................................................ 16
5.3.9 Baud Rate (40136)................................................................................................................ 16
5.3.10 Stop Bits (40137) ..................................................................................................................17
5.3.11 Data Bits (40138) ..................................................................................................................17
5.3.12 Parity Bit (40139) .................................................................................................................. 17
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5.3.13 Response Delay Time (40140)...........................................................................................18
6 M-Bus Gateway ...................................................................................................................19
6.1 M-Bus TCP IP Gateway ..............................................................................................................19
6.2 M-Bus UDP IP Gateway .............................................................................................................19
6.3 M-Bus Communication .............................................................................................................20
6.3.1 Connecting Communication Bus......................................................................................20
6.4 M-Bus Settings ............................................................................................................................21
6.4.1 About M-Bus..........................................................................................................................21
6.4.2 M-Bus Addressing ................................................................................................................22
6.5 M-Bus Configuration Registers................................................................................................22
6.5.1 Counter of Received Messages (30015)..........................................................................22
6.5.2 Counter of Sent Messages (30017).................................................................................. 22
6.5.3 Counter of Alarms (30019)................................................................................................. 23
7 iSMA-B-MG-IP WEB Configuration..................................................................................24
7.1 Web Server Access.....................................................................................................................24
7.2 Device Page..................................................................................................................................24
7.3 M-Bus Configuration..................................................................................................................24
7.4 RS485 Configuration..................................................................................................................25
7.5 IP Configuration ..........................................................................................................................26
7.6 Device Management..................................................................................................................27
7.7 Contact..........................................................................................................................................27
8 List of Modbus Registers ..................................................................................................28
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1 Introduction
The iSMA-B-MG-IP device (meter gateway) has been created to convert data from
Modbus RTU/ASCII and M-Bus protocols to corresponding TCP IP protocols (Modbus TCP
IP and M-Bus TCP IP) and M-Bus UDP IP protocols. The iSMA-B-MG-IP meter gateway
allows to use one type of these conversions or both at the same time, using the same
Ethernet connection.
The iSMA-B-MG-IP allows to service up to 128 Modbus RTU/ASCII devices with unique
addresses connected to a COM1 port and up to 60 M-Bus meters (with unique
addresses) connected to an M-Bus interface. At the same time the iSMA-B-MG-IP can
manage up to 2 M-Bus UDP IP clients, 4 M-Bus TCP IP clients, 4 Modbus TCP IP clients,
which means it can effectively manage 10 clients.
The figure below shows an example of a system with iSMA-B-MG-IP.
Figure 1. An example of Modbus TCP/IP to RS485 gateway and M-Bus TCP/IP to M-Bus gateway
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1.1 Revision History
Rev. Date Description
1.0 24 Jan 2017 First edition
1.1 14 Dec 2017 Added new Modbus registers: HW version, MAC
address;
Added RS485_BIASING bit in STOP_BITS registers;
Added possibility to deactivate RS485_BIASING in
hardware version 2.5 and newer
Added new elements on built-in web page: HW
version, RS485 biasing;
1.2 26 Oct 2018 Corrections of typing errors in the text
Added imperial unit of measure
1.3 15 Nov 2018 Added M-Bus extended star and tree topology
1.4 11 Feb 2019 Added MBUS BAUD RATE (32-bits) registers
Added MBUS CONNECTION TIMEOUT (32-bits)
registers
1.5 8 Jun 2020 Company data update
M-Bus UDP IP protocol update
Modbus function 0x17 read/write multiple registers
Modbus function 0x2B to read the VENDOR_NAME,
MODEL_NAME, FW_VERSION, HOMEPAGE
Supporting Modbus address 0xFF for communication
with gateway (IP module)
1.6 25 May 2022 Rebranded
Table 1. Revision history
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2 Safety Rules
Improper wiring of the product can damage it and lead to other hazards. Make sure
that the product has been correctly wired before turning the power on.
Before wiring or removing/mounting the product, make sure to turn the power off.
Failure to do so might cause an electric shock.
Do not touch electrically charged parts such as power terminals. Doing so might cause
an electric shock.
Do not disassemble the product. Doing so might cause an electric shock or faulty
operation.
Use the product only within the operating ranges recommended in the specification
(temperature, humidity, voltage, shock, mounting direction, atmosphere, etc.). Failure
to do so might cause a fire or faulty operation.
Firmly tighten the wires to the terminal. Failure to do so might cause a fire.
Avoid installing the product in close proximity to high-power electrical devices and
cables, inductive loads, and switching devices. Proximity of such objects may cause an
uncontrolled interference, resulting in an instable operation of the product.
Proper arrangement of the power and signal cabling affects the operation of the entire
control system. Avoid laying the power and signal wiring in parallel cable trays. It can
cause interferences in monitored and control signals.
It is recommended to power controllers/modules with AC/DC power suppliers. They
provide better and more stable insulation for devices compared to AC/AC transformer
systems, which transmit disturbances and transient phenomena like surges and bursts
to devices. They also isolate products from inductive phenomena from other
transformers and loads.
Power supply systems for the product should be protected by external devices limiting
overvoltage and effects of lightning discharges.
Avoid powering the product and its controlled/monitored devices, especially high
power and inductive loads, from a single power source. Powering devices from a single
power source causes a risk of introducing disturbances from the loads to the control
devices.
If an AC/AC transformer is used to supply control devices, it is strongly recommended
to use a maximum 100 VA Class 2 transformer to avoid unwanted inductive effects,
which are dangerous for devices.
Long monitoring and control lines may cause loops in connection with the shared
power supply, causing disturbances in the operation of devices, including external
communication. It is recommended to use galvanic separators.
To protect signal and communication lines against external electromagnetic
interferences, use properly grounded shielded cables and ferrite beads.
Switching the digital output relays of large (exceeding specification) inductive loads can
cause interference pulses to the electronics installed inside the product. Therefore, it
is recommended to use external relays/contactors, etc. to switch such loads. The use
of controllers with triac outputs also limits similar overvoltage phenomena.
Many cases of disturbances and overvoltage in control systems are generated by
switched, inductive loads supplied by alternating mains voltage (AC 120/230 V). If they
do not have appropriate built-in noise reduction circuits, it is recommended to use
external circuits such as snubbers, varistors, or protection diodes to limit these effects.
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3 Technical Specification
Power Supply Voltage 24 V AC/DC ± 20%
Power consumption At 24 V
DC
At 24 V AC
5 W 7.5 VA
RS485 Interface RS485 Up to 128 devices
Communication
protocols
Modbus RTU, Modbus ASCII set by switch
Baud rate From 2400 to 115200 set by switch
Address 0 to 99 set by switch
M-Bus Interface M-Bus Up to 60 devices
Baud rate From 300 to 38400
Ethernet 1 Fast Ethernet IP Interface
Baud rate 10/100 Mb/s
USB USB Mini USB 2.0
Ingress
protection
IP IP40
Temperature Storage -40°C to 85°C (-40°F to 185°F)
Operating -10°C to 50°C (14°F to 122°F)
Humidity Relative 5% to 95%
Connectors Type Removable
Maximum cable size 2.5 mm2(18-12 AWG)
Dimensions Width 110 mm (4.331 in)
Length 37 mm (1.457 in)
Height 62 mm (2.441 in)
Table 2. Technical specification
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4 Hardware Specification
4.1 Dimensions
Figure 2. The iSMA-B-MG-IP dimensions
4.2 Power Supply
Figure 3. DC voltage connection
Figure 4. AC voltage connection
4.3 Grounding and Shielding
In most cases controllers are installed in enclosures along with other devices, which
generate electromagnetic radiation (for example, relays, contactors, transformers, motor
invertors, etc.). Such electromagnetic radiation can induce electrical noise into both
power and signal lines, as well as direct radiation into the controller, causing negative
effects on the system. For this reason, an appropriate grounding, shielding, and other
protective steps should be taken at the installation stage to prevent negative
electromagnetic radiation effects, for example:
control cabinet grounding;
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cable shield grounding;
using protective elements for electromagnetic switching devices;
proper wiring;
consideration of cable types and their cross sections;
and other.
4.4 Firmware Version and Device Type (30001)
The type and firmware version of device are encoded in the 30001 Modbus register.
Low byte contains information about the type of device. In case of iSMA-B-MG-IP it is 5910
(0x3B16).
High byte contains the device firmware version multiplied by 10.
For example:
In the 30001 register the number is 1511410 = 0x3B0A16. It means that it is a iSMA-B-MG-
IP device (0x3B) with firmware in version 1.0 (0x0A16 = 1010).
4.5 Uptime (30012)
This 32-bits register contains information about uptime (in seconds). The value is reset
after a power cycle.
4.6 Device Actions (40001)
Setting the 40001 register according to the table below enables 1 of 3 available actions:
reset device, reload settings, and set to default.
Value [dec] Value [hex] Action
511 0x01FF Reset
767 0x02FF Reload settings
1023 0x03FF Set to default
Table 3. Device actions
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4.7 Front Panel
4.7.1 LED Indicators
Figure 5. The iSMA-B-MG-IP LED indicators
The power LED (ON) is on (green) if the device is running properly.
The communication M-BUS LED is on (green) for 20 ms after sending each message by
the M-Bus bus. If the device receives/sends a lot of messages, the LED can be lit
continuously.
The communication COM1 LED is on (orange) for 20 ms after sending each message
by the RS485 port. If the device receives/sends a lot of messages, the LED can be lit
continuously.
The communication ETH1 LED is on (orange) for 20 ms after sending each message by
the Ethernet. If the device receives/sends a lot of messages, the LED can be lit
continuously
The ALM LED is ON (green) if an overload is detected on the M-Bus bus (current on the
M-Bus bus exceeds 130 mA).
4.8 Default Settings
Out-of-the-box device, as well as after restoring default values procedure, has the
following default registers values:
Register Name Default Value
BAUD RATE 115200 (115200 bps)
STOP BITS 1
DATA BITS 8
PARITY BITS 0
RESPONSE DELAY 0
USERNAME platform
PASSWORD 1000
IP ADDRESS 192.168.1.123
MASK 255.255.255.0
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Register Name Default Value
GATEWAY 192.168.1.1
HTTP PORT 80
MODBUS TCP PORT 502
MODBUS TCP TIMEOUT 60 s
RS485 TIMEOUT 500 ms
SEND MODBUS ERRORS DISABLE
MBUS BAUD RATE 2400
MBUS TCP PORT 6021
MBUS UDP PORT 10002
Table 4. Default values
4.8.1 Restoring Default Settings
To restore the default configuration of all registers, follow the steps below:
Turn off the power supply.
Set section 6 of the S3 switch to on.
Turn on the power supply, power LED is blinking.
Switch section 6 of the S3 switch to off to restore the default settings. To cancel the
reset, turn off the power, and switch section 6 of S3 switch to the off position.
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5 Modbus Gateway
Figure 6. iSMA-B-MG-IP as a Modbus gateway
The device simultaneously supports up to 4 Modbus TCP clients. If the fifth device is to
be connected to the device, a TCP connection will be rejected. In order to secure the
device before filling up the call list, a mechanism for monitoring each Modbus TCP
connection was introduced. There is a parameter called Modbus TCP Connection
Timeout (by default, 60 s); if there is no request from the Modbus TCP client during this
time, the device will close the connection.
To read internal registers of the device, it needs to generate the correct Modbus TCP
frame with address according to the setting of a DIP switch. If the address is different, the
frame will be sent to the COM1 port.
If the device receives an incorrect Modbus TCP frame, it sends back a frame with an error
code:
0x01 - if the function code in the query is not supported;
0x02 - if the address of the register is invalid;
0x03 - if the amount of data disagrees in the query.
If the query is correct, the device instantly generates answer with data or
acknowledgment of receipt of data, depending on the query.
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The iSMA-B-MG-IP has a built-in Modbus TCP/IP toModbus RTU/ASCII gateway, which
allows to connect Modbus meters or other Modbus devices using the RS485. In order to
ensure proper operation of the Modbus gateway, please make sure that all parameters of
RS485 (baud rate, stop bits, etc.) for all the devices connected to RS485 (gateway and
Modbus meters/Modbus devices) are the same.
Operation of the gateway is based on checking the Modbus address in the Modbus TCP
query. If the address is different from the set on the DIP switch, data frame from the
query is converted to Modbus RTU/ASCII, and sent to the COM1 port. Then, the meter
gateway waits for an answer from the device connected to the COM1. If the slave device
does not respond within the estimated time defined by the RS485 Timeout (by default,
500 ms), an exception response will be given: error code 0x0B. If the slave device answers
the correct frame, it is converted to Modbus TCP, and sent to the master device.
The meter gateway sends an error code 0x0B in case the valid frame is not received.
Upon receipt of this error code, some systems do not repeat the query according to the
settings. No retry may cause the point to immediately go to down mode. That is why the
meter gateway has the ability to block the sending information about errors (Send
Modbus Errors setting in the web page or iSMA Configurator). Then, in absence of any
response, the system retries the request according to the settings.
5.1 Communication
5.1.1 RS485 Connection
Figure 7. RS485 connection
RS485 Network Termination
Transmission line effects often present problems for data communication networks.
These problems include reflections and signal attenuation.
To eliminate the presence of reflections of signal from the end of the cable, the cable
must be terminated at both ends with a resistor across the line adequate to its
characteristic impedance. Both ends must be terminated since the propagation is
bidirectional. In case of an RS485 twisted pair cable this termination is typically 120 Ω.
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5.2 Modbus Settings
5.2.1 Setting Modbus Address
To determine the address on the Modbus network, the device has two rotary switches, S1
and S2, located on the top panel of the device.
It is possible to set the device address from 0 to 99.
The formula for setting the address is as follows:
Address = S2 •10 + S1,
where S1 and S2 are values of switches.
For example:
Figure 8. Setting Modbus address with rotary switches
Switches set as in figure above will set the device address to 11.
5.2.2 Setting Baud Rate
Transmission baud rate is determined by the S3 DIP switch (sections 1, 2 and 3) in
accordance with the following table:
1 2 3 Baud Rate
Off (0) Off (0) Off (0) Defined by the user in the register
Off (0) Off (0) On (1) 76800
Off (0) On (1) Off (0) 4800
Off (0) On (1) On (1) 9600
On (1) Off (0) Off (0) 19200
On (1) Off (0) On (1) 38400
On (1) On (1) Off (0) 57600
On (1) On (1) On (1) 115200 (factory set)
Table 5. Setting baud rate
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5.2.3 Setting Protocol
Protocol selection is made by sections 4 and 5 of the S3 DIP switch according to the table:
4 5 Protocol
Off (0) Off (0) Modbus RTU
Off (0) On (1) Modbus ASCII
On (1) Off (0) N/A
On (1) On (1) N/A
Table 6. Setting protocol
5.3 Modbus Configuration Registers
5.3.1 Device Address (30002)
This register contains information about the address of the Modbus device. This address
is set by using switches S1 and S2 (see Modbus Settings section).
5.3.2 Baud Rate and Protocol (30003)
The register contains information about the baud rate of COM1 port and the type of
protocol in accordance with the table below. This register reflects the state of the S3 DIP
switch.
Baud rate Protocol
Bit 0 Bit 1 Bit 2 Baud rate Bit 3 Bit 4 Protocol
0 0 0 User defined 0 0 Modbus RTU
0 0 1 76800 0 1 Modbus ASCII
0 1 0 4800 1 0 N/A
0 1 1 9600 1 1 N/A
1 0 0 19200
1 0 1 38400
1 1 0 57600
WARNING!
Changing the parameters configuring a transmission (except for registers which value
is read from the switch) will only take effect after restarting the device.
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Baud rate Protocol
1 1 1 115200
Table 7. Setting baud rate and protocol
5.3.3 Counter of Received Messages (30004)
The 32-bit register with the number of valid Modbus messages received by the device
from last powering up. The value is reset after a power cycle or after changing
transmission parameters (speed, stop bits, parity, etc.).
5.3.4 Counter of Error Messages (30006)
The 32-bit register with the number of error Modbus messages received by the device
from last powering up. The value is reset after a power cycle or after changing
transmission parameters (speed, stop bits, parity, etc.).
5.3.5 Counter of Sent Messages (30008)
The 32-bit register with the number of Modbus messages sent by the device from last
powering up. The value is reset after a power cycle or after changing transmission
parameters (speed, stop bits, parity, etc.).
5.3.6 Hardware_Version (30130)
This 16-bits register contains the module hardware version multiplied by 10.
5.3.7 MAC_Address (30131)
This 32-bits register contains the module MAC address information.
5.3.8 Device Actions (40001)
Setting the 40001 register according to the table below will enable 1 of 4 available
actions: reset module, reload settings, set to default, and enter bootloader.
Value Action
511 Reset
767 Reload settings
1023 Set to default
1279 Enter Bootloader
Table 8. Device actions
5.3.9 Baud Rate (40136)
If sections 1, 2, and 3 of the S3 DIP switch are in off position, the baud rate is determined
in accordance with this register. Baud rate is determined by the following formula:
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Baud rate = Register value • 10
5.3.10 Stop Bits (40137)
Number of stop bits is determined on the basis of this register in accordance with the
following table:
Value No. of Stop Bits
1 (default) 1
2 2
256 RS485 biasing*
Table 9.
Bit no. 8 activates RS485 biasing resistors in order to pull up voltage on the RS485 bus. If
the bit no. 8 is true (bit 8 = 1), then RS485 biasing resistors are activated. The function is
only available in MG-IP devices with a hardware version 2.0 or higher.
The biasing resistors are useful in case the iSMA modules are connected with a third part
devices with the same RS485 bus and communication errors appears on the network.
Figure 9. Modbus frame
5.3.11 Data Bits (40138)
Number of data bits transmitted in a single byte is determined according to the following
table:
Value No. of Data Bits
7 7
8 (default) 8
Table 10. Data bits
5.3.12 Parity Bit (40139)
Each byte of data being transferred may have additional protection as a parity bit added
before stop bit (bits).
The method of calculating parity bit determines the table below:
WARNING! Only one single device in the network can have biasing resistors activated!
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Register Value Type of Parity Bit
0 (default) None
1 Odd (number of all ones in a byte is odd)
2 Even (number of all ones in a byte is even)
3 Always 1
4 Always 0
Table 11. Parity bit
5.3.13 Response Delay Time (40140)
The value of this 16-bits register determines the number of milliseconds to wait before
the device answers the question. This time is used to extend the interval between
question and answer. The default value of 0 means no delay (the answer is sent once
during the 3.5 character required by the Modbus RTU protocol).
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6 M-Bus Gateway
Figure 10. The iSMA-B-MG-IP M-Bus gateway
The iSMA-B-MG-IP serves as an M-Bus gateway using either one of two protocols: TCP IP
or UDP IP.
6.1 M-Bus TCP IP Gateway
The device simultaneously supports up to 4 M-Bus TCP clients. If the fifth device is to be
connected to the meter gateway, TCP connection will be rejected. In order to secure the
meter gateway before filling up the call list, a mechanism for monitoring each M-Bus TCP
IP connection was introduced. Every 45 seconds a query is sent to the devices connected
to the bus. If a device does not response to the query, after 2 seconds another query is
sent. If the device does not respond three times, the meter gateway closes the
connection.
The iSMA-B-MG-IP device has a built-in M-Bus TCP IP to M-Bus interface gateway, which
allows to connect additional 3rd party M-Bus devices using the bus. In order to ensure
proper operation of the M-Bus gateway, please make sure that the baud rate of the M-
Bus interface of all the devices connected to the bus (gateway and an addition devices)
are the same.
Operation of the gateway is based on sending the M-Bus TCP IP query by the M-Bus. Data
frame from query is converted to M-Bus and sent to the bus. Then the iSMA-B-MG-IP
device waits for an answer from a device connected to the bus; if the meter does not
respond within the estimated time defined by the M-Bus Timeout parameter (by default,
2000 ms), an exception is returned: error code 0x0B. If the slave answers the correct
frame, it is converted to M-Bus TCP IP and sent to the master.
6.2 M-Bus UDP IP Gateway
The device simultaneously supports up to 2 M-Bus UDP clients. In order not to miss the
second client’s packet delivery at high intensity periods of incoming data, the data from
the first client is read from the lwIP in the loop, and only two frames are buffered with
different addresses. The response via the UDP protocol is sent to the same port it came
from (the default port for UDP protocol is 10002).
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Figure 11. UDP packets delivery
Both TCP and UDP protocols share the M-Bus interface:
Figure 12. M-Bus shared interface
6.3 M-Bus Communication
6.3.1 Connecting Communication Bus
Figure 13. M-Bus start topology
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