2. Kamstrup
  3. M-Bus Master

Kamstrup M-Bus Master Installation and User Guide

  • Hello! I've reviewed the Installation and User Guide for the M-Bus Master MultiPort 250D and understand its functionality as a master, repeater, or level converter. This document provides comprehensive information on connecting meters, using communication ports, and utilizing features like the web server and PIN protection. The guide explains how to configure addressing and troubleshoot the network. I'm here to assist with any questions you might have about this device.
  • What is the maximum number of meters that can be connected to the M-Bus Master MultiPort 250D?
    What communication speeds are supported?
    Can this device be used as a repeater?
    What are the different port types?
M-Bus Mster MultiPort 250D
Instlltion nd User Guide
Kmsrup A/S · Indusrivej 28, Silling · DK-8660 Sknderborg · T: +45 89 93 10 00 · info@kmsrup.com · kmsrup.com
2 Kmstrup A/S • 5512853_D2_GB_10.2019
M-Bus Mster MultiPort 250D
Contents
1 Introduction 4
1.1 Design 4
2 Functionlity 5
2.1 Overview of functions 7
3 Connections 8
3.1 Overview of connections 9
3.2 Power supply 10
3.3 USB 10
3.4 RS-232 14
3.5 RS-485 15
3.6 Opticl eye 15
3.7 M-Bus Output 15
3.7.1 Current nd voltge 15
3.8 M-Bus Repeter Input 16
4 Cbling 17
4.1 Specil fetures of
M-Bus Mster MultiPort 250D 18
4.2 Electricl conditions in n M-Bus network 18
4.2.1 M-Bus modules 18
4.3 Instlltion prmeters 18
4.3.1 Cble 19
4.3.2 Cble topology 20
4.3.3 Exmples of network sizes 23
5 M-Bus ddressing 24
5.1 Primry ddressing 24
5.2 Secondry ddressing 24
5.3 Enhnced secondry ddressing 24
6 M-Bus communiction 25
6.1 Communiction speed 25
6.2 Trnsprent reding 25
7 Opertion of M-Bus Mster MultiPort 250D 25
7.1 Keys 26
7.2 Light emitting diodes 26
7.2.1 Power 27
7.2.2 Request 27
7.2.3 Dt 27
7.2.4 Overlod 27
7.3 Disply 27
7.4 Menu overview 28
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M-Bus Mster MultiPort 250D
7.5 Meter serch by mens of MultiPort 250D 28
7.5.1 Primry scnning 29
7.5.2 Secondry scnning 30
7.6 Meter reding by mens of MultiPort 250D 31
7.6.1 Meter reding fter scnning 31
7.6.2 Meter reding from the menu Red Meter 32
7.7 Reding M-Bus loggers by mens of
MultiPort 250D 32
7.7.1 Red Logger 32
7.7.2 Disply of logged dt 33
7.8 Settings of MultiPort 250D 34
7.8.1 Dte nd time 35
7.8.2 Contrst 35
7.8.3 M-Bus 35
7.9 Green Mode 37
7.10 Other settings 37
7.11 PIN code 38
7.12 Advnced 38
7.12.1 Reding  specific meter vi the
M-Bus ddress 39
7.12.2 Reding  meter vi secondry ddress 39
7.12.3 View Lst Meter Reding 39
7.12.4 Network Troubleshooting 40
7.12.5 Informtion loggers 40
7.12.6 Fctory settings 41
7.12.7 Communiction Test 41
7.12.8 Bus Info 42
7.12.9 Restrt mster 42
7.12.10 About M-Bus Mster MultiPort 250D 42
8 Web Server 43
9 Dimensioned drwings 44
10 Technicl dt 45
11 Ordering numbers 46
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M-Bus Mster MultiPort 250D
1 Introduction
M-Bus is  bus system, which is specilly suited for reding wter, het, cooling, gs nd electricity consumption
meters.
An M-Bus system consists of n M-Bus Mster nd  number of meters with M-Bus interfce. A network cn include
different meter types nd brnds. The cble type used is typiclly twisted pir copper.
The connected meters re red either directly by the mster with dt ppering on the mster’s disply or by  reding
progrm which is connected to one of the mster’s communiction ports.
The mster powers the M-Bus slve modules in the meters. Bttery supplied meters thereby chieve  longer bttery
lifetime.
The mximum size of n M-Bus network using Kmstrup M-Bus Mster MultiPort 250D is 250 meters. If  number of
msters re configured s repeters nd coupled in cscde nd only secondry ddressing is used,  totl of 1,250
meters cn be connected, nd the totl cble length cn be up to pprox. 14 km.
If primry ddressing is used, up to 250 meters cn be connected.
Communiction in the M-Bus network is synchronous seril bit trnsmission in hlf duplex, which mens tht it is only
possible to communicte in one direction t  time.
Communiction speed cn be 300, 2400 or 9600 bud.
It is not necessry to connect  PC to the mster during instlltion, mintennce nd troubleshooting in the M-Bus
network s the mster itself includes the functions needed. Opertion is crried out vi disply nd front keys.
M-Bus is stndrdized ccording to EN 13757-2 nd EN 13757-3.
1.1 Design
M-Bus Mster MultiPort 250D is built into  solid cbinet, which complies with protection clss IP 67.
The front consists of  bcklit LCD, 6 keys, 4 sttus LEDs nd n opticl eye.
The power supply is  switch mode type which enbles you to connect the mster to  power supply between 100 nd
240 volts. The frequency must be 50-60 Hz.
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M-Bus Mster MultiPort 250D
2 Functionlity
Kmstrup M-Bus Mster MultiPort 250D is n M-Bus mster designed for the connection of up to 250 meters with
M-Bus interfce. The cble length of  mster cn be up to 2800 m depending on cble type.
The mster supports primry, secondry nd enhnced secondry ddressing. Enhnced secondry ddressing is
supported when the mster is used s level converter, not when reding vi the disply.
All inputs re glvniclly seprted from the M-Bus network.
When designing the mster, it hs been considered importnt tht instlltion nd nlysis work cn be effected
directly from the mster without hving to connect  PC with dedicted softwre.
Configured s  mster, MultiPort 250D is operted vi its disply nd the six front keys.
The disply hs been designed with  user-friendly menu structure, which mkes it simple to perform scnning,
reding nd nlysis of the M-Bus network. Furthermore, the disply currently provides informtion on network sttus
such s current communiction nd number of connected meters (Unit Lods).
Configured s  level converter, one or severl of the integrted communiction ports re connected to  reding
system,  control unit or similr. Communiction is controlled from the connected units.
MultiPort 250D cn be ccessed from ll vilble communiction ports. The integrl port controller prevents collision
in cse of simultneous communiction through more thn one port.
When the port controller detects communiction on one port, communiction on other ports becomes impossible.
When communiction on one port is finished, ll ports re open to communiction.
The repeter function mkes it possible to extend the size of the M-Bus network both s to number of meters nd totl
cble length. If one mster nd four repeters re instlled in  network, the totl cble length cn be extended to
pprox. 14 km, nd up to 1250 meters cn be connected.
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M-Bus Mster MultiPort 250D
602
602
602
602
602
602
602
602
602
602
602
602
602
602
602
602
602
602
602
602
250 meters 250 meters 250 meters
With 4 repeters, up to 1250
meters nd 14 km cble length
M-Bus Mster
M-Bus Repeter M-Bus Repeter ......
Up to 14 km2.8 km2.8 km
RS-232, RS-485, USB
RS-232: 15 m
RS-485: 1200 m
USB: 5 m
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+25
24+2553+5424+2553+54
The integrted web server enbles remote opertion of the mster s to configurtion, scnning nd reding vi RS-
232, RS-485 nd USB.
Opertion vi keys nd communiction through the opticl eye cn be protected by  PIN code.
Four light emitting diodes indicte the sttus of mins supply, dt communiction s well s possible overlod nd
short-circuit of the M-Bus network.
Kmstrup M-Bus Mster MultiPort 250D hs been designed for instlltion indoors. The protection clss cn be up to IP
67.
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M-Bus Mster MultiPort 250D
2.1 Overview of functions
• Usble s mster, repeter nd level converter
• Bcklit 128 x 64 pixels LCD
• Reding vi disply of both Kmstrup meters nd third-prty brnds
• Supports primry, secondry nd enhnced secondry ddressing
• Collision detection with brek signl
• Up to 250 slves per mster
• Integrted repeter function
• Up to four repeters in  system =  totl of 1250 meters
• Up to 14 km cble length
• 300, 2400, nd 9600 bud communiction speed
• Byte recovery
• Echo suppression
• Trnsient protection
• Integrted USB, RS-232, RS-485 nd opticl eye with utomtic port controller
• All ports re trnsprent nd glvniclly seprted from the M-Bus network
• Integrted web server for remote configurtion, nlysis nd reding
• PIN code protection of keybord nd opticl eye
• Event loggers for M-Bus mster nd M-Bus network
• Cble connection vi 9 PG cble glnds
• Locl nd remote updte of firmwre for future functionlity
• Up to IP 67 protection clss.
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M-Bus Mster MultiPort 250D
3 Connections
All connections in MultiPort 250D re screw terminls
with mx. cble size of 2 mm2.
The protection clss of M-Bus Mster MultiPort 250D cn
be up to IP 67. IP 67 mens full dust protection s well
s wter tightness for minimum 30 minutes down to 1
metre.
In order to obtin the highest IP protection, the cbles
used must be correctly mounted through the mster’s
unions.
USB RS-485
RS-232 4 sets of
M-Bus outputs
M-Bus input for
cscde mode
Mins 100-230 V
50/60 Hz
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M-Bus Mster MultiPort 250D
3.1 Overview of connections
Connection number on
mster
Designtion Colour/connector No. Description
Power supply
134 N Blue Neutrl
135 L Brown Live
136 PE Yellow/green Protective erth
USB 2.0 Mx recommended cble length: 5 m
130 VCC Red/1 5 V power supply
131 D- White/2 Dt -
132 D+ Green/3 Dt +
133 GND Blck/4 Ground
RS-232 Mx recommended cble length: 15 m
105 RxD 2 Received Dt
106 TxD 3 Trnsmitted Dt
107 GND 5 Ground
108 DTR 4Dt Terminl Redy
109 CTS 8 Cler To Send
111 DSR 6 Dt Set Redy
112 RTS 7Request To Send
RS-485 Mx recommended cble length: 1,200 m
137 A/- Trnsmit/Receive inverted
138 A+ Trnsmit/Receive non-inverted
139 GND Ground
M-Bus Repeter Input Jumper must be set to Repeter
53 L1 M-Bus input to mster in repeter mode
54 L2 M-Bus input to mster in repeter mode
M-Bus Mster Output 4 sets connection terminls, connection in prllel
24 L1 M-Bus output from mster to meters
25 L2 M-Bus output from mster to meters
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M-Bus Mster MultiPort 250D
3.2 Power supply
The power supply of M-Bus Mster MultiPort 250D is the switch mode type which requires voltge between 100 V nd
240 V. The frequency cn be 50 Hz or 60 Hz.
The mins cble is connected to the mster through the ssocited glnd. The dimeter must be between 4 nd 8 mm.
The mster is supplied without mins cble nd we recommend  fixed instlltion, i.e. without using  mins plug s
this would reduce relibility of opertion.
3.3 USB
M-Bus Mster MultiPort 250D’s USB connection cn be used for M-Bus communiction on n equl bsis with the other
seril connections.
The following communiction speeds cn be used for M-Bus communiction:
• 300 bud 8E1
• 2400 bud 8E1
• 9600 bud 8E1
USB version 2.0, which llows up to 5 m cble length, is used. In connection with other USB versions thn 2.0, the
mximum cble length recommended is 3 m.
The mster’s integrted port controller mkes sure tht communiction is only possible on one seril port t  time.
The mster is vilble with  fctory-mounted 145 cm cble fitted with  USB connector type A.
1 2 3 4
USB connector type A
To be ble to communicte with M-Bus Mster MultiPort 250D vi USB, the corresponding USB driver must be instlled
on the computer used for reding.
The progrm is vilble on Kmstrup’s home pge.
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M-Bus Mster MultiPort 250D
From www.kmstrup.com, nvigte to ”Service & Support”, nd click on “Go to downlods”.
On the new pge, scroll down to the „M-bus Mster“ re, clik on “Go to downlod”, nd you will see this pge:
Click the „Downlod USB driver“ link. You will now be sked to select „Run“ or „Sve“. When selecting „Run“, the
instlltion strts utomticlly.
When the progrm is retrieved, it is sved under C:\Kmstrup\M-Bus Mster 250D.
When selecting „Sve“, the popup br chnges to:
Click “Run”, or “Open folder” to run “KmstrupMBusUSB.exe”.
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M-Bus Mster MultiPort 250D
When the setup progrm hs been strted, just follow the instructions in the wizrd.
Click ”Next” to continue or ”Cncel” to stop the setup.
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M-Bus Mster MultiPort 250D
The Device Driver Instlltion wizrd strts to run.
Depending on the security settings in your computer, this
popup my occur.
Pressing „Finish“, the instlltion is completed.
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M-Bus Mster MultiPort 250D
3.4 RS-232
M-Bus Mster MultiPort 250D’s RS-232 connection cn be used for M-Bus communiction on n equl bsis with the
other seril connections.
The following communiction speeds cn be used for M-Bus communiction:
• 300 bud 8E1
• 2400 bud 8E1
• 9600 bud 8E1
Mximum recommended cble length is 15 m.
The mster’s integrted port controller mkes sure tht communiction is only possible on one seril port t  time.
The mster is vilble with  fctory-mounted 145 cm RS-232 cble fitted with  DB9F femle connector.
1
2
3
4
5
6
7
8
9
RS-232 connector type DB9F
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M-Bus Mster MultiPort 250D
3.5 RS-485
M-Bus Mster MultiPort 250D’s RS-485 connection cn be used for M-Bus communiction on n equl bsis with the
other seril connections.
The following communiction speeds cn be used for M-Bus communiction:
• 300 bud 8E1
• 2400 bud 8E1
• 9600 bud 8E1
Mximum recommended cble length is 1,200 m.
The mster’s integrted port controller mkes sure tht communiction is only possible on one seril port t  time.
3.6 Opticl eye
M-Bus Mster MultiPort 250D’s opticl eye cn be used for M-Bus communiction on n equl bsis with the other
seril connections.
The following communiction speeds cn be used for M-Bus communiction:
• 300 bud 8E1
• 2400 bud 8E1
• 9600 bud 8E1
The mster’s integrted port controller mkes sure tht communiction is only possible on one seril port t  time.
3.7 M-Bus Output
All meters in n M-Bus network re connected to M-Bus output terminls 24 nd 25. The mster includes four sets of
connections coupled in prllel.
3.7.1 Current nd voltge
Bus mrk/spce 41 V DC/28 V DC
Detection level, communiction 7 mA
Detection level, collision 25 mA
Mx norml operting current 375 mA
Wrning level, operting current 377 mA - Overlod LED flshes
Overlod level, operting current 500 mA - Overlod LED is constntly illuminted
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M-Bus Mster MultiPort 250D
3.8 M-Bus Repeter Input
Kmstrup M-Bus Mster MultiPort 250D cn be used s
both mster nd repeter.
Used s mster, up to 250 meters cn be connected in
n M-Bus system.
The repeter function mkes it possible to extend the
size of the M-Bus network both s to number of meters
nd totl cble length. If one mster nd four repeters
re instlled in  network, the totl cble length cn be
extended to pprox. 14 km, nd up to 1250 meters cn be
connected.
The mster is configured s repeter by plcing the
jumper on the connector mrked Repeter. Using n
M-Bus Mster MultiPort 250D s  repeter, the M-Bus
network in front of the repeter is connected to ”M-Bus
Repeter In” on terminls 53 nd 54. The following meters
re connected to M-Bus Out on terminls 24 nd 25.
Position of mster/repeter jumper.
Setting s mster or repeter.
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M-Bus Mster MultiPort 250D
The mster’s disply shows tht it is
configured s  repeter.
When the mster is configured s 
repeter, only the menu points which
cn be used with this configurtion
re displyed.
250D configured s repeter. Min menu when 250D is configured s
repeter.
If the repeter is not connected to  mster or repeter vi terminls 53
nd 54, the symbol shown in the top right-hnd corner is displyed.
Note: The power supply MUST be switched off during reconfigurtion
between mster nd repeter.
4 Cbling
Typiclly unshielded twisted pir cble up to pprox. 1.5 mm2 is used. The cbling topology is typiclly str or bus or 
combintion of both. The connection in M-Bus is independent of polrity nd no termintion resistnce t the end of
the cbling is needed.
If  cble type with shield is used, it is importnt tht the two M-Bus conductors re not connected to ground or shield.
No precise indiction s to mximum cble length in n M-Bus network cn be given s it depends on vrious
prmeters.
The two most importnt prmeters to consider when selecting cble for n M-Bus instlltion re cble resistnce
nd cble cpcity. Generlly speking, the resistnce limits the number of M-Bus slves, nd the cpcity limits the
communiction speed.
Furthermore, we recommend keeping  certin distnce between M-Bus cbles nd other cbles in order to minimize
noise from high-power electric mchinery.
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M-Bus Mster MultiPort 250D
4.1 Specil fetures of M-Bus Mster MultiPort 250D
M-Bus Mster MultiPort 250D hs been designed with the newest cble driver technology, nd is, therefore, rther
insensitive to the cpcity of the M-Bus network.
Thus, designing n M-Bus network to be used together with M-Bus Mster MultiPort 250D, the limiting fctor s to
possible cble length will primrily be the cble resistnce in the network.
4.2 Electricl conditions in n M-Bus network
According to EN 13757-2, the mximum output voltge from n M-Bus Mster must not exceed 42 V. The output voltge
from M-Bus Mster MultiPort 250D is 41 V.
• If the voltge mesured over terminls 24-25 is 24 V or more t the most distnt meter, there is  high degree of
certinty tht ll meters cn be red.
• If the voltge is between 20 nd 24 V, it will probbly be possible to red ll meters.
• If the voltge is between 18 nd 20 V, the meter my be red.
• If the voltge is below 18 V, it is most likely tht the meter cnnot be red.
There must be no communiction on the M-Bus network when the bove mesurement is mde.
4.2.1 M-Bus modules
Ech M-Bus module lods the M-Bus network too. According to the stndrd, n M-Bus module should lod the
network with 1 unit lod (UL) corresponding to 1.5 mA. Some modules, however, lod with up to 4 UL.
Cpcitively the lod of n M-Bus module is 0.5 – 1 nF.
The number of connected M-Bus slves is shown on the disply of M-Bus Mster 250D. Plese note tht it is not
possible to show the exct number of connected slves. This is due to tolernces in the slves.
4.3 Instlltion prmeters
The following prmeters re essentil to the possible cble length of n M-Bus network.
19Kmstrup A/S • 5512853_D2_GB_10.2019
M-Bus Mster MultiPort 250D
4.3.1 Cble
The cble resistnce nd cpcity must be s low s possible. The thicker the cble, the lower the resistnce. The
thicker the cble, the higher the cpcity.
An M-Bus cble must s  minimum be ble to hndle 50 V nd 500 mA.
Dimeter (mm ø) Cross section (mm2)Resistnce in Ohm
per 1,000 metres Length in metres per Ohm
0.5 0.20 90 11
0.65 0.33 53 19
0.8 0.50 35 29
1.0 0.79 23 45
1.13 1.00 18 57
1.26 1.25 14 71
1.39 1.52 12 87
1.6 2.0 8.7 115
Exmples of resistnce in copper cble.
Plese note tht the resistnce in copper depends on its purity. The purer the copper, the lower its resistnce.
LiYY 2x0.34 mm22x0.50 mm22x0.75 mm22x1.0 mm22x1.5 mm2
Current lod Mx 4.5 A Mx 6 A Mx 10 A Mx 12 A Mx 18 A
Cble resistnce 56 /km 39 /km 26 /km 20 /km 12 /km
Cpcity 110 nF/km 120 nF/km 120 nF/km 120 nF/km 120 nF/km
J-Y(St)YY 2x0.60 mm22x0.80 mm2
Current lod - -
Cble resistnce 65 /km 37 /km
Cpcity 120 nF/km 100 nF/km
Exmples of cble types.
20 Kmstrup A/S • 5512853_D2_GB_10.2019
M-Bus Mster MultiPort 250D
In big networks using secondry ddressing, worst cse
lod must be considered s 250 slves of 1 UL (Unit Lod)
ech drwing 5.4 A, which thin cbles will not be ble to
withstnd.
Plese note tht resistnce cn be stted in two different
wys in cble specifictions, i.e. s cble resistnce or s
loop resistnce.
Loop resistnce is the totl resistnce mesured through
the two conductors. Cble resistnce is the resistnce
through one conductor. Therefore, loop resistnce is
lwys twice the cble resistnce.
Mesurement of loop resistnce.
Mesurement of cble resistnce.
4.3.2 Cble topology
An M-Bus network normlly uses bus or str topology or  combintion of both.
The dvntge of bus topology is shorter wires. The disdvntge is tht  cble interrupt will men tht ll the
following meters cn no longer be red.
The dvntge of str topology is the fct tht ll the other meters cn still be red fter  cble interrupt. The
disdvntge is  lrge consumption of cble with  high leding lod, which reduces the mximum cble length nd
mkes  reduction of communiction speed necessry, respectively.
Bus topology offers two solutions. One solution is to loop the cble through ech meter. This solution presupposes tht
there is room for two cbles nd tht the connection terminls re prepred for the connection of two sets of cbles. All
connections re thereby typiclly mde inside the meter.
The other solution is to use bus topology with ech individul meter connected to the bus. With this solution,  number
of connections must be estblished on the bus itself.
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