ATOP MB5904D Rugged Serial to Ethernet Modbus Gateway
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The ATOP MB5904D is a 4-port DIN-rail Modbus gateway that converts Modbus RTU/ASCII on four RS-232/422/485 serial ports to Modbus TCP over two Ethernet ports. It runs from -40°C to +85°C on 12-48 VDC with redundant power inputs or an optional 802.3af PoE input, and offers optional 3 kV serial isolation. It suits meters, IEDs and RTUs polled periodically by a SCADA or PLC.
Serial Ports4 × RS-232/422/485 (DSub9 or terminal block), optional 3 kV isolation
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Description
4‑Port Industrial Secure Modbus TCP/RTU/ASCII Gateway with optional 3kV isolation, DIN‑rail mount, dual power input, wide‑temperature.
Modbus Gateway supports the four most commonly used communication standards, RS-232/485/422, and Ethernet. The ease-of use configuration utility provided with Modbus Gateway can quickly select the hardware interface , and easily switch to the existing communication infrastructure. Industrial EMC protection and wide temperature operation capability make MB5904D ready for every mission. And if cabling is an issue, the PoE-powered version can allow MB5904D to be powered through PoE.
MB5904D specifications
| Modbus Function | Modbus TCP to Modbus RTU/ASCII gateway (entry-level tier); concentrator build sold as MB5904D-CT |
|---|---|
| Serial Ports | 4 × RS-232/RS-422/RS-485, full function |
| Serial Interface | DSub9 or terminal block |
| Serial Isolation | 3 kV (optional) |
| RJ45 Ports | 2 × 10/100BASE-T(X) (RJ45 option) |
| Fibre (SFP) Slots | 2 × 100/1000BASE-X SFP (SFP option, in place of RJ45) |
| Redundancy Protocols | RSTP on 2 redundant Ethernet ports |
| Protocols | Modbus TCP, Modbus RTU, Modbus ASCII |
| Modbus Features | Gateway, concentrator (-CT), redundancy option, exception error handling |
| Modbus Function Codes | 1, 2, 3, 4, 5, 6, 15, 16, plus 43 Read Device Identification (server side only), per ATOP's Modbus protocol specification |
| VPN | IPsec VPN or OpenVPN |
| Relay Output | 1 |
| Input Voltage | 12-48 VDC |
| PoE Input | IEEE 802.3af powered device (optional) |
| Power Redundancy | Yes, redundant power inputs |
| Management | ATOP configuration utility |
| Mounting | DIN-rail |
| Ingress Protection | IP30 |
| Dimensions | 55 × 145 × 113 mm (L × H × D) |
| Operating Temperature | -40°C to +85°C |
| Storage Temperature | -40°C to +85°C |
| Certifications | UL 61010-2-201, CE/FCC, EN 60950-1 and/or EN 62368, industrial EMC protection |
Specifications taken from the manufacturer datasheet.
Which version do I need?
This page covers the MB5904D gateway. ATOP offers the same 4-port DIN-rail platform in two builds: MB5904D, the entry-level gateway for periodic polling, and MB5904D-CT, the concentrator that polls the serial slaves automatically into internal memory. On the MB5904D itself, the two Ethernet ports are ordered either as 10/100BASE-T(X) RJ45 or as 100/1000BASE-X SFP, and 3 kV serial isolation and 802.3af PoE input are options. Choose SFP when the uplink is fibre, and isolation where serial field wiring is long or exposed to surges.
Typical applications for the MB5904D
- Bringing Modbus RTU meters, IEDs and sensors onto a Modbus TCP SCADA network
- Substation panels needing port isolation and VPN between serial devices and the network
- Periodic polling of energy meters in plant switchrooms
- DIN-rail panels in unheated or hot enclosures from -40°C to +85°C
- Sites without a local DC supply, powered from an 802.3af PoE switch
- Fibre uplinks from remote serial Modbus devices using the SFP option
Complete the stack
Products that work with this one — connect it, power it, and get it online.
MB5904D — frequently asked questions
How many serial and Ethernet ports does the MB5904D have?
Four RS-232/422/485 serial ports on DSub9 or terminal-block connectors, and two Ethernet ports ordered either as 10/100BASE-T(X) RJ45 or as 100/1000BASE-X SFP. The two Ethernet ports support RSTP redundancy.
What is the difference between the MB5904D and the MB5904D-CT?
The MB5904D is ATOP's entry-level Modbus gateway: it translates Modbus TCP requests to Modbus RTU/ASCII and suits periodic data polling. The MB5904D-CT concentrator polls the serial slaves automatically and holds their data in internal memory, so Modbus TCP masters get immediate replies without timeouts, with customisable register mapping and link status and timestamp access.
What power supply does it need?
12-48 VDC on redundant power inputs. An 802.3af PoE powered-device input is available as an option, so the gateway can be fed from a PoE switch where no local DC supply exists.
What temperature range is it rated for?
-40°C to +85°C operating and -40°C to +85°C storage, in an IP30 DIN-rail housing measuring 55 × 145 × 113 mm.
Is serial isolation available?
Yes, 3 kV serial isolation is an ordering option. ATOP cites port isolation and VPN on the MB5904D as a way to stop faults and attacks on one side of the gateway from propagating to critical devices on the other.
Which certifications does it carry?
ATOP's selection guide lists UL 61010-2-201, CE/FCC and EN 60950-1/EN 62368 with industrial EMC protection. It is not listed for IEC 61850-3 or IEEE 1613; ATOP's IEC 61850-3 Modbus models are the rack-mount MB5908A and MB5916A.
Which Modbus function codes are supported?
ATOP's Modbus protocol specification lists function codes 1, 2, 3, 4, 5, 6, 15 and 16, plus 43 (Read Device Identification) on the server side, with exception codes 1, 2, 3, 4 and 6 returned to the master.
How much does the ATOP MB5904D Rugged Serial to Ethernet Modbus Gateway cost in the UK?
The ATOP MB5904D Rugged Serial to Ethernet Modbus Gateway is supplied to order and priced on application. Send a quote request and we confirm the price and lead time in writing, usually the same working day. No account is needed. Indiott is a UK distributor invoicing with VAT (PSI Technologies Ltd, VAT GB 730 2340 83).
What is the lead time and delivery cost for the ATOP MB5904D Rugged Serial to Ethernet Modbus Gateway?
The ATOP MB5904D Rugged Serial to Ethernet Modbus Gateway is supplied to order. We confirm the lead time in writing with your quote, before you commit to anything. UK delivery is a flat £14.25 per order ex VAT, whatever the weight or how many items you order. We ship to GB and the EU and provide a VAT invoice with every order.
