HRW BACnet HPE-MRBN User manual

HRW Limited Unit E, 11/F, Sun Ying Industrial Centre Ph [phone]
9 Tin Wan Close, Tin Wan Fax [phone]
Hong Kong www.hrw.hk
HPE-MRBN – BACnet MS/TP Gateway to Modbus RTU 485
FW4.01
Integration of BACnet MS/TP conforming devices in to Modbus RTU based systems. Up to 247 BACnet
MS/TP devices may be connected to the gateway for read access of up to 250 BACnet data objects
Typical Applications
Modbus RTU 485 network integration of BACnet MS/TP devices:
 HVAC Controllers
 PMAC770 electricity meters (c/w BACnet module)
 Sontex SC531 chilled/hot water energy integrators (c/w BACnet module)
 Belimo energy Valves *
* Belimo energy valves should have dedicated gateway, with System Vendor ID# 423 (SV=423) set in the gateway.
Other BACnet devices may share a gateway, with default SV=0 setting.
Feature Summary
 Modbus RTU RS485 slave port (BMS port)
 BACnet MS/TP master-slave/token-passing (Sub-bus port)
 User customised BACnet object data based
 Modbus Long Integer and IEEE Floating Point register address ranges
 Smart-polling of BACnet objects (only actively polled when active on the Modbus BMS side)

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OPERATION OVERVIEW .................................................................................................................................... 3
MODBUS SLAVE DEVICE ........................................................................................................................................ 3
Long Integer .....................................................................................................................................................3
IEEE Floating Point.........................................................................................................................................3
Write & Relinquish...........................................................................................................................................3
BACNET NETWORK GATEWAY .............................................................................................................................. 4
TERMINAL MODE ................................................................................................................................................ 5
HYPERTERMINAL SETTINGS ................................................................................................................................... 5
Additional Settings............................................................................................................................................6
Connecting at 76800 Baud Rate.......................................................................................................................6
Saving HyperTerminal Settings........................................................................................................................6
BREAK IN TO TERMINAL MODE .............................................................................................................................. 6
MODBUS CONFIGRATION COMMANDS ........................................................................................................ 7
BACNET CONFIGURATION COMMANDS ...................................................................................................... 8
DATA BASE MAPPING TOOL............................................................................................................................. 9
TERMINAL OPERATION ................................................................................................................................... 10
DOWNLOAD TEXT FILE ........................................................................................................................................ 10
ENABLE BACNET MS/TP PORT ........................................................................................................................... 11
VERIFY BACNET NETWORK COMMUNICATION ................................................................................................... 11
INSTALLATION & COMMISSIONING ........................................................................................................... 12
POWER & RS485 .................................................................................................................................................. 12
CONNECTIONS .................................................................................................................................................... 13
DIMENSIONS ........................................................................................................................................................ 13
TECHNICAL DATA ............................................................................................................................................. 14
ORDERING INFORMATION ............................................................................................................................. 14
HPE-MRBN ........................................................................................................................................................ 14
ACCESSORIES ....................................................................................................................................................... 14
OTHER HP_MR SERIES DEVICES ......................................................................................................................... 14

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Operation Overview
The gateway comprises two sections; the Modbus RTU device and the BACnet MS/TP network reading
data base.
Modbus Slave Device
Important for testing with Modscan or other similar test applications:
 Gateway Modbus points 1, 2 & 3 are Short Integers (16 bit). These diagnostic-counter points
should not be included in your testing process
 When testing with Modscan, set up for 32 bit registers (Long Integer or IEEE Float32) and start
your test routine from point 4 or higher
During commissioning the following should be configured:
 Node # (local network address)
 RS485 network baud rate
 250 registers relating to the BACnet network devices’ data objects being read
Long Integer
 Registers 4, 6, 8… 502
 Modicon Register Addresses, using F03/Holding Register as example, 40005,
40007, 40009… 40503
IEEE Floating Point
 Registers 1004, 1006, 1008… 1502
 Modicon Register Addresses using, F03/Holding Register as example, 41005,
41007, 41009… 41503
Write & Relinquish
The gateway operates on the BACnet side with Null priority by default. To facilitate some level
of BACnet priority control we implement a command level address range 2004…2502 to avoid
other BACnet devices overriding the BMS.
Example for point 4:
 If you wish to lock in the BMS write value such as a setpoint then send a value of 1 to
register 2004 (2004=1)
 To relinquish back to Null send a value of 17 to register 2004 (2004=17)
 We recommend that the connected BACnet devices have all objects in the relinquished
state

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BACnet Network Gateway
250 BACnet Objects may be configured, from up to 247 BACnet MS/TP devices.
It is important to have the BACnet device manufacturer’s manual available to assist with BACnet Object
settings.
The gateway data base consists of 250 Modbus registers, each configured with a target BACnet
object’s data:
1. BACnet device address where the object resides (MS/TP Node address / MAC)
2. Object type (BI, BV, BO, AI, AV, AO, MI, MV, MO)
3. Object Instance (object number)
Separately the BACnet network baud rate and Maximum Master value must be set. The gtaeway is
generally set as being Device Instance 0.

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Terminal Mode
An HPECOMU (USB) data cable is used for terminal mode between the gateway and a PC running a
terminal program. HyperTerminal or Indigo Terminal Emulator from Shade Blue are recommended.
The USB driver for the HPECOMU may be found on our web site.
The following settings reflect HyperTerminal. Please contact us if you require assistance setting up
Indigo.
HyperTerminal Settings
For successful communication between HyperTerminal and the device, initial Properties setup of
HyperTerminal should be as per the screen prints below.
‘Connect to’ Comm Configuration: ‘Settings’ General:
‘Settings’ ASCII Setup:
9600

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Additional Settings
Some PC platforms may need keyboard response adjustment for initial Terminal Mode success. These
settings may be done via the PC Control Panel >> Keyboard Settings:
 Fastest Repeat rate
 Shortest Delay time
 Fastest Cursor Blink rate
Connecting at 76800 Baud Rate
Because HyperTerminal does not support 76800 baud then after setting to 76800 the device baud rate
will remain at 9600 baud for HyperTerminal communication and switch to 76800 after Writing the new
baud rate and eXiting terminal mode.
To allow later terminal communication a device set with 76800 baud will operate at 9600 baud for the
first 5 seconds after a power-up. If no attempt to connect the terminal at 9600 baud is made within 5
seconds of a power-up then the device will automatically switch to 76800 for normal network operation.
Saving HyperTerminal Settings
For ease of connection it is recommended to save the HyperTerminal setup for each baud rate you may
wish to use with an easily recognised configuration name. For example:
 HPECOM 24 (2400)
 HPECOM 48 (4800)
 HPECOM 96 (9600)
 HPECOM 19.2 (19200)
 HPECOM 38.4 (38400)
 HPECOM 57.6 (57600)
Break in to Terminal Mode
To break in to terminal mode set Caps Lock on and hold the ‘T’ character key continuously
(TTTTTTT…). After five (5) T’s have been sent to the device it will switch to terminal mode.

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Modbus Configration Commands
Function Enter Result Options / Comments
Start
communication TTTTT(TTT…) Break in to Terminal mode
With the Caps Lock on, hold the T key down
until the screen updates with HPE data. It is
not necessary to press the enter key to start
communication.
Set node address 1000=1…98,
100…247
Network node number is
assigned
Example: 1000=1
N
ode address 99 is not allowed
Set RS485
network baud
rate
1001=… Network comms speed is
set
2400, 4800, 9600, 19200, 38400, 57600,
76800 Example: 1001=38400
After changing comm. speed it will be
necessary to reconnect with HyperTerminal
at the new comm. speed to save (write) the
change!
Zero the Reset
counters 1=0 All Reset counters are zeroed
Factory diag. In order as displayed:
R
x timeout, Tx timeout, Hardware reset
Zero the BACnet
comms error
counte
r
2=0 BACnet comms error
counter is reset Example: 2=0
Zero the M-Bus
comms error
counter
3=0 M-Bus comms error counter
is reset Example: 3=0
Write values as
default W Changes written. Always do this after making changes that you wish to be permanent
Exit
communication X
Communication with
HyperTerminal no longer
active
Auto X after 240sec without key entry. After
eXit unplug the HPECOM cable to allow
network communication to take place

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BACnet Configuration Commands
Function Enter Result Options / Comments
Start
communication TTTTT(TTT…) Break in to Terminal mode
With the Caps Lock on, hold the T key down
until the screen updates with HPE data. It is
not necessary to press the enter key to start
communication.
Set BACnet
baud rate 1002=… Network comms speed is set
9600, 19200, 38400, 57600, 76800
Example: 1002=19200
Set BACnet
address 1003=0 Set the gateway’s BACnet
MS/TP address
Typically addr 0, as the gateway is considered
to be the MS/TP network router
Set BACnet
Device Instance DI=1…4194303 Set the gateway’s BACnet unique address
Can be left at default as a wider BACnet based
system does not exist if this gateway is being
employed
Set Maximum
Master MM=1…127 Set the highest numbered
BACnet device’s address
This setting acts to limit address polling only
up to the MM value, for network efficiency
Prepare for point
data base text file
download
DE
‘Ready’ will be displayed at
which time the relevant text
file should located and sent
to the gateway
Data base lines may also be manually entered,
one by one
Delete current
point data base
DE followed by
10000=1
Any configuration of point
4…502 is deleted
Download of a text file with new data base will
delete an old existing data base as a matter of
course
Enable BACnet
subnet
communication
E
Toggles Enabled/Disabled of
M-Bus Subnet
communication
Default Disabled to allow easy configuration
when no devices are connected. Always
‘Enable’ when devices are connected and
points are configured!
Scroll page
display P=1…10
Scroll to specific page if
more data-points are present
than can be displayed on
one screen
Example: P=2
The second page of database settings are
displayed
Diagnostic
display D
Point by point response
codes are displayed each
time ENTER is pressed
For data stream analysis between the HPE and
the BACnet devices. Create text capture file for
easy analysis of the received data stream
Release
manualled points R
Enter R to release all
manualled points. Enter
R=n(nn) to release specific
individual points
n(nn) represents a specific point number in
the range 4…502
Write values as
default W Changes written. Always do this after making changes that you wish to be permanent
Exit
communication X
Communication with
HyperTerminal no longer
active
Auto X after 240sec without key entry. After
eXit unplug the HPECOM cable to allow
network communication to take place

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Data Base Mapping Tool
Although all configuration can be typed directly in to the gateway via the terminal program, by email
request or by download from www.hrw.hk, Resources/Tools, you can use our the HPE-MRBN mapping
Tool for creation of a table of data base settings which can be downloaded to the gateway as a text file
(*.txt).
As well as the generic BACnet mapping tool, we also have Belimo-device-specific mapping tools available on
request.
Copy the Download Table lines from the tool to Notepad text file and save for download to the gateway:

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Terminal Operation
After entering terminal mode with TTTTTTTT you will initially see the factory default settings.
Make settings such as Modbus address & baud rate by entering the required settings. Note that after
changing the Modbus baud rate the terminal mode baud rate is also changed so reconnect
HyperTerminal at the newly set baud rate and then Write (W) the new setting.
Download Text File
Enter DE. The display will indicate that the existing data base is being blanked and now ‘Ready’ to
receive data base text file:
While in the ‘Ready’ state, navigate to the text file path via the Transfer / Send Text File dialogue:

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After download of the text file the display will indicate a check between lines received and lines
expected (indicated by the 10000=n line count generated in the mapping tool configuration table).
If the lines check is correct then the new data base is loaded, otherwise the old data base will be
reinstalled automatically.
Enable BACnet MS/TP Port
Enter E to enable the BACnet MS/TP communication and enter W to write the enabled state so that it
will still be enabled after a power failure.
Note: To disable enter E again to toggle from enabled to disabled state.
Verify BACnet Network Communication
In terminal mode any scanning of the BACnet network will only occur after the data based points are
added to the Log list:
1) Enter L to place all points on log
2) Enter X to eXit terminal mode so that the gateway freely scans the BACnet network
3) Wait 30 seconds to ensure all points are read in
4) Enter TTTTTTT to go back in to terminal mode
5) Enter D to invoke Diagnostic display (display of true scaled values, as opposed to raw data)

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Installation & Commissioning
Power & RS485
 This is an RS485 network device designed for indoor use, mounted in a dry electrical panel.
Ideally it should be mounted to the panel backplane in a horizontal position (RJ11 sockets on
the lower side and communications ports on the upper side)
 Each 24Vac power supply transformer should have the neutral (24Vac N) connection grounded
at the electrical panel earth connection to ensure the device grounding is at the same potential
as the network master’s grounding
 Where more than one device is connected to a common transformer ensure that the 24Vac
phasing is the same to each device (‘A’ connects to ‘A’, ‘N’ connects to ‘N’ in all cases)
 If the red comms light adjacent to the RS485 terminals emits an obvious flash every time 24Vac
power is applied to the device then the micro-processor may be corrupted. The micro processor
should be replaced
 RS485 multi-drop cable should be used for the network connections, complete with end of line
terminating resistors (120Ω). Belden 9841 or equivalent is recommended. The recommended
cable is a low capacitance twisted pair with braid and foil screen
 The RS485 cables should be terminated directly at each device in a daisy-chain configuration,
avoiding ‘laterals’ or ‘spurs’
 The RS485 screen should be connected at the network master’s ground terminal. The incoming
and outgoing screen at each device should be continuously connected via the S terminal of the
device (note that the device’s S terminal has no electrical connection to the device, it merely
acts as a junction terminal for the purpose of screen continuity)
 The RS485 cable should avoid cable routes that run with power cables. Where the RS485
cable must cross power cables then they should cross at 90° avoiding parallel runs beside
power cables
 Prior to connection of the slave devices to the RS485 network check that no AC voltage is
present. Double check the network for short circuits between the twisted pair cores and
between the cores and the screen. Ensure continuity of the twisted pair cores and the screen
 Check the network master’s +/- terminals for correct voltages to ground (approx. 2.5Vdc) and
connect the RS485 network cable to the network master’s RS485 port
 At each device assign an individual address and the baud rate specific to the network. Write the
changes, eXit the terminal application and remove the HPECOM cable
 Verify network voltage at the RS485 connector (between +/- and ground) and connect to the
device. Communication can be verified by flashing of the red comms LED adjacent the 3
terminal RS485 connector). Frequency of comms LED flash is baud rate dependant. At higher
baud rates the LED flash may not be obvious, the LED appearing to be continuously on
 Where a network runs between buildings and zero earth potential difference between individual
panel 24Vac power supplies cannot be guaranteed, we recommend that a repeater be used to
provide isolation of the sections of the network having differing earth potential

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Connections
Dimensions
If using HDA0002 DIN rail adapter brackets the overall depth from the gear plate to the front surface of
the device is 45.5mm

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Technical Data
Network Wiring
RS485 Comms Speed
RS485 Network Capacity
Power Supply
Conformity & approvals
Operating Temperature Range
Storage Temperature Range
Humidity Range
Dimensions
Shielded twisted pair (shield grounded)
Belden 9841 low capacitance twisted pair for RS485 networks
(braided + foil shield, shield continuous throughout the network and
grounded at network origin)
RS485 - 2400, 4800, 9600, 19200, 38400, 57600, 76800 baud
247 nodes over max. 1.2km without repeater
24Vac, 50/60 Hz, max. 7.5VA
0…50ºC (32…122ºF)
-5…75ºC (-40…167ºF)
10…95%rH (non-condensing)
126mm (W) x 107mm (H) x 34.5mm (D)
Ordering Information
HPE-MRBN
Description: 250 point gateway – Modbus RTU 485 integration of BACnet MS/TP device, for
control panel mounting
Standard package: 40 units per carton
Accessories
HDA0002 DIN rail adapter brackets, factory fitted
HPECOMU Configuration cable (USB)
Other HP_MR Series Devices
HPC0662MR Universal Controller, 12 Point, Modbus RTU, 24Vac
HPC8884MR Universal Controller, 28 Point, Modbus RTU, 24Vac
HPD0440BNMR Network HMI / Universal Ctrl / Scheduler / Modbus RTU gateway
8 Point, BACnet MS/TP, 24Vac
HPD0460MR Network HMI, 12 Point, Modbus RTU, 24Vac
HPD0460MRC Network HMI / Universal Controller, 10 Point, Modbus RTU, 24Vac
HPD0460MRCT Network HMI / Universal Ctrl / Scheduler, 10 Point, Modbus RTU, 24Vac
HPD0460MRT Network HMI / Scheduler, 10 Point, Modbus RTU, 24Vac
HPE0662MR I/O expansion, 12 Point, Modbus RTU, 24Vac
HPE8884MR I/O expansion, 28 Point, Modbus RTU P, 24Vac
HPV0662MR VAV / Universal Controller, 13 Point, Modbus RTU, 24Vac
HPE-MRSMA Modbus gateway for SMA inverter devices, 250 point, 24Vac
Also available are gateways for Modbus RTU devices in to BACnet MS/TP and P1 FLN based networks

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Notes: