introduction to mp-bus technology - belimo · introduction to mp-bus technology ... fax: +41 61 461...

Application A9-0001

www.belimo.com A9-0001 • en • v1.1 • 04.2010 • Subject to changes

IntroductiontoMP-BusTechnology

#Tools-009-E-4

TableofContents

1. Introduction to MP-Bus Technology p. 32. Network topologies for MP-Bus p. 33. Sensor linking p. 34. Connection on the MP Master p. 45. MP-Bus cable p. 66. MP-Bus cable lengths p. 77. Override operation functions with MP-Bus operation p. 98. Special MP-Bus application: bus wiring for connecting the PC-Tool for diagnostics

and maintenance of VAV-Compact xMV-D2-MPp. 11

9. MP accessory devices p. 1210. Bus fail positions adjustable with PC-Tool V3 p. 1411. Diagnostics on a MP network with the PC-Tool MFT-P p. 1512. Diagnostics on a MP network with the ZTH-VAV as MP-Bus tester p. 1913. MP specifications p. 20

A9-0001 MP-BusTechnology

2 / 23 A9-0001 • en • v1.1 • 04.2010 • Subject to changes www.belimo.com

TableofContents

1. IntroductiontoMP-BusTechnology p. 32. NetworktopologiesforMP-Bus p. 33. Sensorlinking p. 3

3.1 Sensor connection on MFT or MP/MFT2 actuators p. 44. ConnectionontheMPMaster p. 4

4.1 Data exchange between master and slave p. 44.2 Connection to an MP Cooperation Node p. 54.3 Connection to an MP Gateway p. 5

5. MP-Buscable p. 66. MP-Buscablelengths p. 7

6.1 Cable lengths with AC 24 V and DC 24 V p. 76.2 Cable lengths with on-site supply p. 8

6.2.1 Mains device for ZN230-24MP for local on-site supply p. 87. OverrideoperationwithMP-Bus p. 9

7.1 Restrictions p. 97.2 Wiring diagram for override operation with a MP gateway p. 97.3 Wiring diagram for override operation with MP cooperation nodes p. 107.4 Wiring diagram for override operation with one ZN230-24MP for DC 24 V p. 10

8. SpecialMP-Busapplication:buswiringforconnectingthePC-ToolfordiagnosticsandmaintenanceofVAV-CompactxMV-D2-MP

p. 11

9. MPaccessorydevices p. 129.1 ZN230-24MP p. 129.2 BKN230-24MP p. 129.3 ZIP-USB-MP p. 129.4 ZIP-RS232 p. 129.5 ZIP-232-MP p. 139.6 MP I/O Module UST-3 from BV-Control p. 139.7 MP-Bus combination sensor PTH from BV-Control p. 14

10. BusfailpositionsadjustablewithPC-ToolV3 p. 1411. DiagnosticsonaMPnetworkwiththePC-ToolMFT-P p. 15

11.1 MP-Master simulation p. 1511.1.1 MP-Bus scan p. 1511.1.2 Recording a trend p. 1511.1.3 Wiring diagrams p. 16

11.2 MP-Bus monitoring p. 1711.2.1 Analysis with the MP monitor p. 1711.2.2 Wiring diagrams p. 18

12. DiagnosticsonaMPnetworkwiththeZTH-VAVasMP-Bustester p. 1913. MPspecifications p. 20

13.1 Brief description of communications p. 2013.2 MP signal level p. 2013.3 Query interval p. 21


www.belimo.com A9-0001 • en • v1.1 • 04.2010 • Subject to changes 3 / 23

1.IntroductiontoMP-BusTechnology

The MP-Bus is the BELIMO master/slave bus. Up to 8 slaves can be connected to a MP master unit: MP/MFT(2) damper actuators, MP/MFT(2) valve actuators, MP fire damper actuators and MP VAV devices.

2.MP-Busnetworktopologies

There are no restrictions with respect to network topology. Permissible topologies include star, ring, tree and mixed configurations.

MP-Master

Slave

Slave

Slave

Slave

Slave

Slave

SlaveSlave

Slave

MP-MasterSlave Slave

Slave Slave

Slave

Slave Slave

MP-Master

Slave

Slave

Slave

Slave

Slave

Slave

SlaveSlave

3.Sensorlinking

One sensor can be connected per MP/MFT(2) actuator in MP-Bus operation. The sensor value is recorded by the actuator and transmitted in digital form via MP-Bus. The scaling and evaluation of the sensor value takes place in the MP Master.Active sensors (output DC 0 ... 10 V) and ON/OFF switches can be connected to the MFT actuators. In addition, passive resistance sensors (e.g.: Pt 1000) can be connected to the MP/MFT2 actuators.

MP-Master

Slave

Slave

Slave

Slave

Slave

Slave

SlaveSlaveS

S

S

S

S

S

S

S



4.ConnectiontoMPMaster

Up to eight MP/MFT(2) actuators can be controlled by one MP master via the MP-Bus. MP masters are MP cooperation nodes (SPS or DDC controllers with MP interface) or MP Gateways (for linkage with a field bus system). The BELIMO PC-Tool MFT-P is also an MP master.

3.1SensorconnectiononMFTorMP/MFT2actuators

MP-Bus

T ~

AC 24 V

DC 24 V

∆p

1 2 3 5 1 2 3 5 1 2 3 5

∆p

1 2 3 5 1 2 3 5

active sensor switch

passive sensor

Max. 8 actuators and sensors

Sensor Module

active sensor switch

MFT actuators MP / MFT2 actuators

Sensor Module

Sensor Module

4.1Dataexchangebetweenmasterandslave

The data transmitted between the MP master and slave is dependent on the MP master and on the type of the actuator. The overview shows the typical data exchange for each actuator category.

Actuatorcategory Transmissionvaluestotheactuator Responsevaluesfromtheactuator

Dampers and valves Setpoint 0..100%Override OPEN, CLOSED, MIN, MID, MAXFault reset

Relative position/stroke in %Absolute position/stroke in ° or mmSensor valueFault message 1)

Operating status (e.g. disengagement push-button)Min/Max limits

Fire dampers Override OPEN, FAST_CLOSEDFault resetTest run

Position switch S1/S2Fault message 2)

VAV Setpoint 0..100% (Vmin..Vmax)Override OPEN, CLOSED, VMIN, VMID, VMAXFault reset

Relative volume flow in %Relative position in %Absolute volume flow m3/sSensor valueFault message 1)

Operating status (e.g. disengagement push-button)Min/Max limits

Fault messages are:

1) Mechanical overload, range increased, Stop&Go ratio2) Mechanical overload, range increased, duct temperature too high, smoke detector triggered, safety-

relevant fault and others.



4.3ConnectiontoaMPGateway

MP-Bus

MP-Bus

T ~AC 24 V- + DC 24 V

LonWorks

MP

24 V ~/+

4.2ConnectiontoaMPCooperationNode

DDC

MP-Bus

MP-Bus

MP

24 V ~/+MP

MP interface



5.MP-Buscable

Communication and supply for the MP-Bus can be carried in the same cable. The voltage supply of the MP/MFT(2) actuators is secured with GND and AC or DC 24 V. The MP master communicates with the connected actuators via the MP communications wire, which is referenced to the same GND as the voltage supply.

~/+T

MPMP

T~/+ ~/+ ~/+T

SupplyAC/DC 24 V MP Master

Neither special cables nor terminating resistors are required. An MP-Bus connection can be set up with commercially available installation cables. Special bus cables are, however, available for simplified wiring.

Example Flat ribbon cable made by Woertz with adapter piece for MP-Bus connection by MP/MFT(2) actuators and sensors.

M

S

M

WoertzAGPostfach 948CH - 4132 Muttenz

Telephone: +41 61 466 33 33 Fax: +41 61 461 96 06E-Mail: [email protected] site: www.woertz.ch

MP actuatorsensor

Bus cable



6.MP-Buscablelengths

The cable length of an MP network is limited:

• by the sum of the consumption data of the connected MP/MFT(2) actuators• by the type of supply (AC by bus / DC by bus / AC locally)• by the cable cross-section

6.1CablelengthswithAC24VandDC24V

TotalpowerratingMP/MFT(2)actuators[VA] TotalpowerconsumptionMP/MFT(2)actuators[W]

DC 24 V

MP

1

1 2 5 1 2 5 1 2 5

2 8

DC 24 VGnd

UK24-LON

1 5

MP-Master

AC 24 V

MP

1 5

1

1 2 5 1 2 5 1 2 5

2 8

AC 24 VGnd

UK24-LONMP-Master

MaximumcablelengthforAC24Vsupply MaximumcablelengthforDC24Vsupply

CalculationofthemaximumcablelengthsThe power consumption [W] of the MP/MFT(2) actuators used is to be added, and the corresponding cable lengths are to be read from the diagram.

Example:The following is connected to the MP-Bus: 1 pc. NM24A-MP, 1 pc. SM24A-MP, 1 pc. LMV-D2-MP… and 1 pc. NV24-MFT2

Total power rating: 3.5 W + 4 W + 3 W + 3 W = 13.5 W

To be read out from the mass of curves:• After cables with wire Ø 0.75 mm2: Cablelength55m• After cables with wire Ø 1.0 mm2: Cablelength75m• After cables with wire Ø 1.5 mm2: Cablelength110m• After cables with wire Ø 2.5 mm2: Cablelength190m

CalculationofthemaximumcablelengthsThe power ratings [VA] of the MP/MFT(2) actuators used are to be added, and the corresponding cable lengths are to be read from the diagram.

Example:The following is connected to the MP-Bus: 1 pc. NM24A-MP, 1 pc. SM24A-MP, 1 pc. LMV-D2-MP… and 1 pc. NV24-MFT2

Total power rating: 5.5 VA + 6 VA + 5 VA + 5 VA = 21.5 VA

To be read out from the mass of curves:• After cables with wire Ø 0.75 mm2: Cablelength28m• After cables with wire Ø 1.0 mm2: Cablelength35m• After cables with wire Ø 1.5 mm2: Cablelength50m• After cables with wire Ø 2.5 mm2: Cablelength90m

Cable length vs active power applies to DC supply (minimum supply voltage DC 24 V)

CablelengthvspowerratingappliestoACsupply(minimumtransformervoltageAC21.6V)

CablelengthvsactivepowerappliestoDCsupply(minimumsupplyvoltageDC24.0V)

Powerrating[VA] Activepower[W]

Cab

lele

ngth

[m]

0.75 mm2 1.0 mm2 1.5 mm2 2.5 mm2

0.75 mm2 1.0 mm2 1.5 mm2 2.5 mm2

Cab

lele

ngth

[m]

In the case of the NVF24-MFT2, the power rating must be multiplied by a Factor of 2.!

Actuator Actuator Actuator

L=max.cablelength[m]

Actuator Actuator Actuator


MPmaster MPmaster



6.2Cablelengthswithon-sitesupply

If the actuators are supplied with AC 24 V locally via a separate transformer, the cable lengths can be significantly increased. Cable lengths remain in accordance with the table, independent of the power rating of the actuators connected and independent of the wire ∅ of the MP wiring.

AC 24 V

MP

1 5

1

1 2 5 1 2 5 1 2 5

2 8

AC 24 V

Gnd

Wire-∅ [mm2] L = max. cable length [m]0.75

8001

1.52.5

6.2.1MainsdeviceZN230-24MPforlocalon-sitesupply

The on-site supply can be accomplished with any commercially available transformer. BELIMO offers a device which is specially suited for on-site supply. The MP/MFT(2) actuators are supplied locally with AC 24 V by the ZN230-24MP. This permits the implementation of long MP-Bus lines. When the ZN230-24MP is utilised, the MP-Bus is comprised solely of a 2-wire line (GND and MP).Sensors can be linked with the MP/MFT(2) actuators via ZN230-24MP. The MFT parameterising device PC-Tool MFT-P can also be linked with the MP/MFT(2) actuator via ZN230-24MP. Communications with the MP network are disconnected as soon as an MFT parameterising device is plugged in at the "Tool" socket. This ensures that data collisions will be prevented.

Sensor 0 ... 50°C outputDC 0 ... 10 V

ZKS-MP(is supplied with the ZIP-RS232)

A USB 2.0 cable with an A to B connector is supplied with the ZIP-USB-MP

MPmaster Actuator Actuator Actuator


3 pole

.............................................................................................................................



7.OverrideoperationwithMP-Bus

It is possible to have override functions act locally on the MP/MFT(2) actuator while it is running on the MP-Bus, i.e. while it is being digitally controlled by the UK24LON - or by a DDC cooperation node via the MP-Bus.

7.1Restrictions

Caution!If the possibility of sensor linkage is used, then the analogue override functions will be switched off.

• The analogue overrides only work if the actuator is supplied with AC 24 V.• The overrides can only be used if the sensor integration on the same MP/MFT(2) actuator is

not used at the same time.

NoteforVAV-CompactxMV-D2-MP The following settings must be carried out with the PC-Tool MFT-P on the VAV-Compact xMV-D2-MP in order to ensure that the override operations function in accordance with the following connection diagram:• Set CAV function to NMV-D2M-compatible• Set mode to 2 ... 10 V

7.2WiringdiagramforoverrideoperationwithaMPgateway

Example Analogue override operation in connection with an application with the UK24LON gateway.

OPE

N *

Max

CLO

SED

Bus

mod

e

..A-MP, ..D2-MP,

..MFT(2) actuator..A-MP, ..D2-MP, ..MFT(2) actuator

..A-MP, ..D2-MP,


additional actuators (total of 8)

NoteWhen the max. position setting in the actuator is configured to 100 % (factory setting), the actuator also opens fully, if there is AC 24 V at terminal 3. Such cases do not require a diode to move the actuator into the override open position. A diode is however mandatory to open the damper completely with the VAV-Compact ..D2-MP. In the case of the ..D2-MP, the maximum position setting corresponds to the volume flow max.

* Not available with DC 24 V supply.



7.3WiringdiagramforoverrideoperationwithMPcooperationnodes

Example Analogue override operation with an application with a DDC MP cooperation node.

GND

MP

AC 24 V

T ~

5

~T

+_

U5

M P

321 5

~T

+_

U5

M P

321 5

~T

+_

U5

M P

321 5

~T

+_

U5

M P

321

AC 24 V

GND AC 24 V

OPE

N *

Max

CLO

SED

Bus

mod

e

..A-MP, ..D2-MP,


..A-MP, ..D2-MP,



DDCcontroller

7.4WiringdiagramforoverrideoperationwithZN230-24MPwithDC24V

Example Analogue override operation with an application with a DDC MP cooperation node to DC 24 V supply. The analogue override operation of the actuator will nevertheless be possible as a result of the AC 24 V provided by the MP supply device ZN230-24MP.

G

ND

AC

24 V

AC

24 V

GN

D

Tool

Ya

MP

Yb

GND

MP

AC 230 V

~

5321

T

+_

U5

MP

xx24-MFT(2)

MP1

S1

ZN230-24MP

GND

MP

DC 24 V

OPE

NM

axC

LOSE

DBu

s m

ode

DDCcontroller


* Not available with DC 24 V supply.



8.SpecialMP-Busapplication:BuswiringforconnectingthePC-ToolfordiagnosticsandmaintenanceofVAV-CompactxMV-D2-MP

The VAV controllers are conventionally activated with a 0 ... 10 V signal from the temperature controller. The individual xMV-D2-MPs are addressed with an MP address, in order to ensure that they can be periodically checked with the BELIMO PC-Tool via MP-Bus.

Advantageofthisapplication The desired xMV-D2-MP can be accessed with the PC-Tool from a central location, e.g. from the control cabinet. This makes it possible to check the functioning of the VAV controllers in simple fashion.

Disadvantageofthisapplication Because of the fact that the xMV-D2-MPs are addressed, U5 is not available as analogue voltage 2 ... 10 V, which displays the current volume flow (%Vnom). This means that master/slave wiring is not possible.

Zone1 Zone2 Zone3 Zone4

NoteThe PC-Tool must be exited after an xMV-D2-MP has been accessed via MP-Bus with the PC-Tool, because otherwise no error-free analogue operation can be guaranteed.


white = GNDblue = not connectedgreen = MP

...........



9.3ZIP-USB-MP

The ZIP-USB-MP is a potential-free interface between the USB port on a PC and the BELIMO MP-Bus. A driver must be installed on the PC in order to use the ZIP-USB-MP. This driver can be downloaded from the BELIMO website (Download section). The device has a slide switch which is used to switch from master to monitor mode.

Application The ZIP-USB-MP is used for parameterizing MP/MFT(2) actuators or analysing MP-Bus networks with the BELIMO PC-Tool. The ZIP-USB-MP is supplied with voltage by the USB port. No external power supply is required. This interface is galvanically separated.

9.MPaccessorydevices

9.1ZN230-24MP

MP supply device for on-site supply. The ZN230-24MP is used for MP applications in connection with general damper adjustment and valve applications. The device is described under 6.2.1 and 7.4.

9.2BKN230-24MP

The BKN230-24MP is identical in construction to the ZN230-24MP, with features for connecting bus-capable BF(G)24TL-T-ST fire damper actuators and smoke switch contact (optional).

9.4ZIP-RS232

The ZIP-RS232 is an interface between the RS232 port on a PC and the MP-Bus from BELIMO.

Application The actuators can be connected in simple fashion using the pressure clamps for the configuration, parameterization or check of the actuators with the BELIMO PC-Tool. In addition, installations with UK24LON or other MP-Bus master devices can be accessed via ZIP-RS232. This interface is galvanically separated.



9.6MPI/OModuleUST-3fromBV-Control

The MP I/O module is manufactured and sold by the company BV-Control (Switzerland). The module is used in situations where analogue or digital signals from/to field devices such as sensors, switches, frequency converters, circuit breakers, etc. are to be connected on the MP-Bus. The module is used in connection with a DDC controller with MP-Bus interface (MP-cooperation node). A corresponding MP command list is provided by BV-Control for the purpose of implementing the MP commands required for the module in the DDC controller at the software level.

• 3 potential-free relay switching outputs for switching power of up to 230 V AC / 3 A.• 1 analogue output 0 ... 11 V / 4 mA.• 1 resistance measurement 0 ... 150 k� (for passive sensors Ni1000, Pt1000, NTC).

Alternate configuration also possible as analogue input 0 ... 11 V.• 3 digital inputs for potential-free contacts.• One of which can be configured alternatively as a 0 ... 11 V analogue input.

The UST-3 is connected together with up to 7 additional MP-Bus nodes (MP/MFT(2) actuators, MP-I/O Module UST-3 or MP sensors) to an MP network and is assigned a corresponding MP address (MP1 ... MP8).

BV-C UST-3

Input/Output-

R1 R2 R3 Tx/Rx

SetAdore

BV-ControlBruechstrasse 27CH - 8706 MeilenSwitzerland

Telephone: +41 - 44 - 923 79 25Fax: +41 - 44 - 790 15 70E-Mail: [email protected]

9.5ZIP-232-MP

ZIP-232-MP for the level conversion between an RS232 interface and the BELIMO MP-Bus. The device is suitable for control cabinet installation.

Application MP master devices with RS232 interface (e.g. PC's) which have implemented the BELIMO MP protocol, but which have no MP level converter of their own, can be connected with the MP-Bus via ZIP-232-MP. This interface is not galvanically separated.



9.7MP-BuscombinationsensorPTHfromBV-Control

The company BV-Control has a combination sensor for pressure, temperature and humidity in its product line that can be connected to an MP network as an autonomous MP-Bus node.The necessary MP commands must be implemented in the MP master in order for the MP master to be able to operate the combination sensor as an MP slave (node), i.e. to read out pressure, temperature and humidity. The corresponding list of MP commands is available from BV-Control.

~/+T

MPMP

T~/+ ~/+

BV-ControlBruechstrasse 27CH - 8706 MeilenSwitzerland

Telephone: +41 - 44 - 923 79 25Fax +41 - 44 - 790 15 70E-Mail: [email protected]

10.BusfailpositionsadjustablewithPC-ToolV3

So-called bus fail positions can be set with the PC-Tool for the actuators of the new generation (MP types). This makes it possible to define how the actuator should behave in the event that it detects that its communication to the MP master is missing (if communication is interrupted, then the actuator will detect this within one minute's time.).

Typicalapplication A valve can, for example, be opened completely in the event of bus failure (frost protection).

Busfailposition Actuatortype

Possiblebusfailpositions,adjustablewithPC-Tool

Settingatthetimeofdelivery(factorysetting)

..24A-MP • Last value (actuator stops)

• Open (actuator opens up entirely)• Close (actuator closes entirely)• Fast close (actuator closes entirely)

• Last value (actuator stops)

..MV-24A-MP • Last value (control operation)• Open (actuator opens up entirely)• Close (actuator closes entirely)• Min / min• Max / max

• Last value (control operation)

NoteThe actuator supply must be secured for this function.

SupplyAC/DC 24 V MP master



11.DiagnosticsonaMPnetworkwiththePC-ToolMFT-P

11.1MPMastersimulation

The PC-Tool will be used as an MP master in the event that an MP master device (MP master DDC controller or MP master gateway) is to be simulated. The functioning of all of the actuators which are connected to the MP-Bus can be checked. This checking also includes the readout of the connected sensors.

Typical functions that can be selected in the PC-Tool MFT-P:• Default entry of nominal values via MP-Bus• Readout of the sensors that are connected to the MP actuators• Recording of graphic trends• MP-Bus scan

11.1.1MP-Busscan

After startup, the PC-Tool checks the MP network with the bus scan function and displays all of the MP slave devices that are integrated into the MP-Bus network.

11.1.2Recordingatrend

One passive sensor is connected to an LM24A-MP actuator.1 = Setpoint actuator2 = Actual value of actuator3 = Sensor value

12

3



11.1.3Wiringdiagrams

Wiringdiagram1

MP-Master

DDC Controller

UK ... Gateway

24 V GND

ZK2-GENBelimo

PC-Tool

RJ11 (4/6)

MP

GND

USB

USB

MP

... A-MP

... D2-MP

... MFT (2)

... A-MP

... D2-MP

... MFT (2)

... A-MP

... D2-MP

... MFT (2)

1 532 1 532 1 532

∆p

MP

24 V

┴

ZIP-USB-MP

Enable

Pos. MA = Master

Data

Initialized

MO

MA

US

B

Wiringdiagram2

AC 24 V

DC 24 V

T

+_

~

UK24LON / EIB

MFT-H

0V 24 V Y U /MPa b

LonTalk MP-Com.

0V 24 V n.c .

Power

ZKS - MP

Belimo

PC-Tool

USB

USB

3 pol

... A-MP

... D2-MP

... MFT (2)

... A-MP

... D2-MP

... MFT (2)

... A-MP

... D2-MP

... MFT (2)

1 532 1 532 1 532

∆p

MP

24 V

┴

ZIP-USB-MP

Enable

Pos. MA = Master

Data

Initialized

MO

MA

US

B

NoteThe PC-Tool is the MP Master. The connection is made with the connection cable ZK2-GEN.The MP connection to the master must be disconnected.

NoteThe PC-Tool is the MP Master. The connection is made with the connection cable ZKS-MP.

Further actuators and sensors (max. 8)







11.2MP-Busmonitoring

The PC-Tool will be used as an MP monitor in the event that the communications of an MP network (communication between an MP master and its MP slaves) are to be checked.The switch of the ZIP-USB-MP must be set to Monitor "MO" position for the analysis at the MP-Bus.

11.2.1AnalysiswiththeMPmonitor

Example 3 actuators (slaves) communicate with the MP master on the MP-Bus.

11.2.2Wiringdiagrams

Wiringdiagram1

MP-Master

DDC Controller

UK ... Gateway

24 V GND

ZK2-GENBelimo

PC-Tool

RJ11 (4/6)

MP

GND

USB

USB

MP

... A-MP

... D2-MP

... MFT (2)

... A-MP

... D2-MP

... MFT (2)

... A-MP

... D2-MP

... MFT (2)

1 532 1 532 1 532

∆p

MP

24 V

┴

ZIP-USB-MP

Enable

Pos. MO = Monitor

Data

Initialized

MO

MA

US

B

Note• The PC-Tool is the MP Master. The connection

is made with the connection cable ZK2-GEN.• The mode switch must first be set to “MO” be-

fore the MP Monitor module can be started up in the PC-Tool.






11.2.2Wiringdiagrams(continued)

Wiringdiagram2

AC 24 V

DC 24 V

T

+_

~

UK24LON / EIB

MFT-H

0V 24 V Y U /MPa b

LonTalk MP-Com.

0V 24 V n.c .

Power

ZKS - MP

Belimo

PC-Tool

USB

USB

3 pol

... A-MP

... D2-MP

... MFT (2)

... A-MP

... D2-MP

... MFT (2)

... A-MP

... D2-MP

... MFT (2)

1 532 1 532 1 532

∆p

MP

24 V

┴

ZIP-USB-MP

Enable

Pos. MO = Monitor

Data

Initialized

MO

MA

US

B





11.DiagnosticsonaMPnetworkwiththeZTH-VAVasMP-Bustester

The VAV adjustment device ZTH-VAV enables efficient testing of VAV and CAV systems. A MP-Bus tester is integrated as an auxiliary function which checks the following items:• Power supply on MP-Bus• Determination of active nodes (slaves)• Determination of non-activated nodes (slaves)• Determination of non-responding nodes (slaves)• Evaluation of data communications (number of telegrams and error rate)• Determination of the MP signal level (High/Low)

Precondition The MP master must communicate actively with all of the connected slaves, i.e. the slaves must receive MP commands (requests) periodically from the master, in order to have complete inspection of the MP trunk. If the MP master is not present, then the BELIMO PC-Tool can be utilised in scan mode. A scanning interval of 15 seconds is recommended for meaningful diagnostics.

Connectionandsupply The connection is made in the control cabinet or at any random location on the MP-Bus.

Daten Ok: 10378

Fehler: MP3=13

OK

ZTH-VAV

MP1

MP4

MP2 MP3

MP8

MP6

MP7

MP-Master

MP5

Procedure It is recommended that the MP-Bus tester be first clamped to the MP cable at the control cabinet. If necessary, the inspection can be repeated at various positions on the MP cable.



13.MPspecifications

13.1Briefdescriptionofcommunications

Communication Master-SlaveThe slave (MP/MFT(2) actuator) responds only to commands from the MP master

Datatransfer Bidirectional, half-duplexCommunication takes place via the U5 connector, referenced to GND.

Communicationparameters 1200 baud, 8 data bits, 1 start bit, 1 stop bit, no parity

NumberofnodesontheMP-Bus The communication protocol is enabled for 1 MP master and 1 ... 8 slaves (MP/MFT(2) actuators).

13.2MPsignallevel

0V

Command Answer

A1 2,00 V 10,0 m/s

Measuringconditions min type max unit

At least one MP/MFT(2) actuator is connected to the MP master. All signals are measured across U5 and GND.

Voltage level highCommand and Answer

11 12.5 18 V

Voltage level lowCommand

1 2.5 V

Voltage level lowAnswer

4 4.5 V



13.3Queryinterval

The more actuators there are to be served on the bus and the more sensors there are to be read at the MP/MFT(2) actuators, the longer the query intervals will be on the BELIMO MP-Bus.The cycle times that result on the MP-Bus are displayed in the curve below.

0

1

2

3

4

5

6

7

8

1 2 3 4 5 6 7 8

Actuators

8 actuators without sensors8 actuators with sensors

Tim

e / s

introduction to mp-bus technology - belimo · introduction to mp-bus technology ... fax: +41 61 461...

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