IN7004851000000 – Modbus RTU/TCP to BACnet Gateway
IN7004851000000 is a compact industrial gateway for Modbus RTU/TCP to BACnet IP/MSTP integration, supporting up to 100 points.
- Stock: 5-7 days
- Brand: Intesis
- Model: IN7004851000000
Full design package: User manual, CE declaration, CAD, PDF, certificates and test reports
If you're preparing technical documentation or an installation design, you can receive a complete set of design materials for this model. This is a quick way to gather the required documents for audits, acceptance, or project documentation.
- Device User Manual
- CE Declaration of Conformity (EU Declaration of Conformity)
- Mechanical Drawings – CAD (STEP/DWG) or high-quality PDF
- Additional Certificates and Test Reports (if available for the model)
Industrial Modbus RTU/TCP to BACnet Gateway (100 points).
The IN7004851000000 model is a compact yet highly functional gateway that enables bidirectional integration of Modbus RTU or TCP devices with BACnet systems – supporting both BACnet IP and MS/TP. It is ideal for building and industrial automation applications that require monitoring and control of Modbus devices from a building management system (BMS).
Commissioning note (BACnet physical layer): the gateway supports BACnet/IP and BACnet MS/TP, but only one BACnet physical layer can be used at a time (BACnet/IP or BACnet MS/TP). In practice, decide early whether your BMS will discover IN7004851000000 over Ethernet (BACnet/IP) or over EIA-485 (BACnet MS/TP), then keep that interface consistent throughout commissioning.
The device complies with the B-AAC profile (BACnet Advanced Application Controller), is BTL-certified (BACnet Testing Laboratories), and ensures full interoperability with BACnet IP and BACnet MS/TP controllers. It supports up to 100 data points, making it a perfect solution for small and medium-sized installations requiring integration between the two popular protocols.
BACnet object model (how points are exposed): to the BACnet side, IN7004851000000 exposes points as standard BACnet objects (e.g., Analog Input, Analog Value, Binary Input, Binary Value, Multistate Input, Multistate Value, etc.) with the key runtime value in Present Value. Each signal is identified by Device + Object Type + Object Instance, which is critical when you troubleshoot mismatched points in a BMS (wrong object type or instance → correct object exists but BMS reads the wrong one).
The gateway is equipped with a rich set of communication interfaces, including:
- Port A – RS485: with 1500VDC isolation and selectable bus termination (120 Ω terminator) and active polarization, configurable via DIP switches.
- Port B – RS485 + RS232: including RS232 with SUB-D9 connector (reserved for future use) and an additional RS485 port with separate termination and polarization settings.
- Ethernet RJ45 10/100 Mbps connector for BACnet IP communication.
Modbus server side – supported function codes: when the gateway acts as a Modbus server (TCP and/or RTU), it supports standard read/write operations: 01 Read Coils, 02 Read Discrete Inputs, 03 Read Holding Registers, 04 Read Input Registers, 05 Write Single Coil, 06 Write Single Register, 15 Write Multiple Coils, 16 Write Multiple Registers. If a client requests a range that includes invalid addresses, IN7004851000000 returns the corresponding Modbus exception—use this behavior as a fast diagnostic for wrong address maps.
Modbus register format (practical mapping detail): all Modbus registers are 2 bytes (MSB…LSB). In the gateway configuration you can define per point: bit width (1/16/32), data coding (unsigned, signed C1/C2, float, bitfields, error comm.) and byte order (Big Endian, Little Endian, Word Inverted Big Endian, Word Inverted Little Endian). This matters when values “look wrong” (e.g., swapped words in 32-bit float) even though communication is healthy.
Power supply is provided through a 3-pin pluggable screw terminal and supports a flexible input voltage range: 9–36VDC ±10% or 24VAC ±10%. LED indicators show device operation, Ethernet connection status, data transmission on ports, and the state of buttons A and B – facilitating diagnostics and commissioning.
Button A (BACnet quick test): in BACnet mode, Button A sends an I-Am message. If your BMS has discovery issues, this is a simple field test: press Button A and check whether the BMS sees a fresh I-Am/Device announcement (helps separate “network discovery” problems from “point mapping” problems).
BACnet/IP networking options: the default BACnet/IP UDP port is 47808 (0xBAC0) (changeable in configuration). For multi-subnet projects, IN7004851000000 can be set as a Foreign Device (to communicate across network domains) or configured as BBMD (BACnet/IP Broadcast Management Device) to manage broadcast distribution across IP subnets—key when discovery works only inside one VLAN/subnet.
BACnet MS/TP (EIA-485) commissioning parameters: for BACnet MS/TP you assign a MAC address to the gateway in the MS/TP segment. Supported MS/TP baud rates are: 9600, 19200, 38400, 76800, 115200, or Autobauding (autodetect). Standard EIA-485 wiring rules apply (polarity, termination, and grounding discipline).
Modbus RTU (EIA-485/EIA-232) serial settings: baud rates: 1200, 2400, 4800, 9600, 19200, 38400, 56700, 115200 bps; 8 data bits; parity: none/even/odd; stop bits: 1 or 2; plus Modbus server address and physical selection (EIA-232 or EIA-485). Physical reminder: EIA-232 uses RX, TX, GND; EIA-485 uses B-, A+, SNGD—respect polarity to avoid “silent” communication failures.
EIA-485 bus rules (fast troubleshooting checklist): maximum distance 1200 m, maximum 32 devices on the bus, and 120 Ω termination at each end. The gateway has internal biasing with termination that can be enabled via DIP switches: Position 1 ON = 120 Ω termination active (OFF = inactive); Position 2 and 3 ON = polarization active (OFF = inactive). If you enable the gateway termination and mount it at one end of the bus, do not add an extra terminator at that same end.
Modbus TCP essentials: Modbus TCP encapsulates Modbus into TCP/IP frames. Configure IP parameters (including DHCP status, IP, netmask, gateway) and TCP port—default is 502. This is a common first check when a SCADA/PLC reports “connection refused” or “timeout”: verify port 502 and routing/VLAN rules.
The compact housing is made of durable plastic (PC, UL 94 V-0) and has dimensions of 90 x 88 x 56 mm, offering IP20 protection. The device can be mounted on a wall or on a DIN rail (EN60715 TH35). With an operating temperature range of 0°C to 60°C and relative humidity up to 95% (non-condensing), it is suitable for use in most industrial and commercial environments.
Old product codes: IBOX-BAC-MBM, INBACMBM1000000. The IN7004851000000 is their direct successor – featuring improved architecture and expanded compatibility capabilities.
Key product features:
- Integration of up to 100 Modbus points with BACnet IP or MS/TP
- Simultaneous support for Modbus RTU (RS485) and Modbus TCP
- Compliance with the B-AAC BACnet profile
- BTL-certified – guaranteed interoperability
- Two independent RS485 ports with termination and polarization configuration
- Easy wall or DIN rail mounting
- LED indicators for status and port activity
- Operation over wide temperature and voltage ranges
- Plastic enclosure with IP20 protection rating
- 36-month warranty
Need help with selection or integration? Contact our technical expert.
Integrator answers: BACnet/IP vs BACnet MS/TP choice, Modbus addressing, RS-485 wiring, BBMD/Foreign Device, and common timeout causes.
? Can IN7004851000000 run BACnet/IP and BACnet MS/TP at the same time? ▾
No. The gateway supports both physical layers, but only one BACnet physical layer can be used at a time. If you select BACnet/IP, then BACnet MS/TP is not active (and vice versa). Decide this early in the project to avoid “discovery works on one side only” confusion.
? BACnet/IP discovery fails across VLANs – what should I check on IN7004851000000? ▾
First confirm UDP port 47808 (0xBAC0) is allowed end-to-end (default). If devices are in different IP subnets, configure IN7004851000000 as a Foreign Device or set it as a BBMD to handle broadcast distribution between network domains. Without BBMD/Foreign Device, BACnet broadcast-based discovery often stays inside one subnet only.
? Which BACnet MS/TP baud rates are supported by IN7004851000000? ▾
Supported MS/TP line rates: 9600, 19200, 38400, 76800, 115200, or Autobauding (autodetect). Assign a valid MAC address for the gateway in your MS/TP segment and apply standard EIA-485 wiring rules (polarity, termination, grounding discipline).
? My Modbus RTU client gets timeouts – what are the must-check RS-485 rules for IN7004851000000? ▾
Use the EIA-485 baseline constraints as a diagnostic checklist:
- Max 1200 m bus length and max 32 devices on one segment.
- 120 Ω termination at each end of the bus.
- Enable gateway termination via DIP: Position 1 ON = 120 Ω active; enable polarization via Position 2 and 3 ON.
- If the gateway is at one end and you enable its termination, do not add another terminator at that same end.
- Respect polarity: EIA-485 uses B-, A+, SNGD on the gateway.
? Which Modbus function codes does IN7004851000000 support (server side)? ▾
It supports standard read/write function codes: 01, 02, 03, 04, 05, 06, 15, 16. If a request includes invalid addresses in a multi-register range, IN7004851000000 returns the appropriate Modbus exception—use that as a quick indicator of wrong mapping rather than a wiring problem.
? Values look “wrong” (swapped/garbled) over Modbus – what mapping setting usually fixes it? ▾
Check data coding and byte/word order for the point. The gateway allows Big Endian / Little Endian and word-inverted variants for 32-bit values (including floats). A classic symptom: communication is stable, but 32-bit values are incorrect → switch the configured byte order or the data format (e.g., float vs signed C2) for that register mapping.
? What are the key Modbus RTU serial settings available on IN7004851000000? ▾
For Modbus RTU you can set: baud rate 1200/2400/4800/9600/19200/38400/56700/115200, 8 data bits, parity (none/even/odd), stop bits (1 or 2), and the Modbus server address. Also select the physical link (EIA-232 uses RX/TX/GND; EIA-485 uses B-/A+/SNGD).
? How can I quickly force BACnet discovery from the device during commissioning? ▾
In BACnet mode, Button A sends an I-Am message. If your BMS is set to listen for announcements, pressing Button A is a quick field test to confirm the BACnet side is alive and reachable (then focus on VLAN/UDP 47808/BBMD settings if the message is not received).
Need help with selection or integration? Contact our technical expert.
