How it works
The gateway does the polling on the serial side, converts each reading into a JSON payload, and publishes it to the topic you configure. If the uplink drops it stores the readings and forwards them on reconnect — see how store & forward works.
Pick the variant that fits the site
same MQTT function, different uplink4G / LTE
No cabling to the site. The gateway carries its own SIM and publishes over the mobile network.
USE IT WHENRemote pumps, DG sets, solar sites, water assets — anywhere pulling a LAN cable is not realistic.
- WT460M4G + Ethernet, Modbus TCP as well+ Modbus TCP
- WT470M4G + Wi-Fi
- WT400M4G, dual-server delivery
- WT410DM4G LITE
- CPCB GatewayPremium · MAX only, OCEMS compliance+ Modbus TCP
LAN / Ethernet
The plant network already reaches the panel. Lowest running cost of the three — no SIM, no data plan, no signal survey.
USE IT WHENIn-plant metering, sub-metering and BMS where the switch is already in the room.
The gateway is a protocol converter too
The uplink itself is a protocol conversion: the gateway speaks Modbus RTU to your field devices and MQTT (or HTTPS) to your server. One box replaces a serial converter plus a separate edge client.
The WT460M, the WT600M and the premium CPCB Gateway carry Modbus TCP alongside RTU, so one unit answers your local SCADA on the plant network while it publishes the same readings upstream. On every other model the Ethernet, Wi-Fi or 4G link is the route to your server — the field side stays RS-485 Modbus RTU.
If nothing needs to reach a broker and you only want serial bridged to Ethernet, the WE62C converter is the cheaper, simpler answer — it is a transparent bridge with no logging or publishing.
What actually lands on your broker
Wiman JSON V3.2{"imei":"860710086587899","uid":1,"dtm":"20260325143500","seq":142,"sig":29,"msg":"log",
"modbus":[{"sid":1,"stat":0,"rcnt":9,
"V_R":235.37,"V_Y":236.12,"V_B":234.88,
"I_R":12.44,"I_Y":11.98,"I_B":12.07,
"PF":0.97,"kW":8.62,"kWh":154237.5}]}Register values carry your own tag names, so the payload is readable at the broker without a decoder ring. CSV is available where a server expects it. Planning a data plan? Payload size drives the monthly cost — see which bands your market uses.
Works with your broker
Broker address, port, topic, credentials and TLS are configured on the device. Nothing is locked to a Wiman cloud — your data goes to your infrastructure.
Questions we get asked
Do I need a separate Modbus-to-MQTT converter?
No. Publishing Modbus data over MQTT is a built-in function of the gateway, not a separate box. Every Wiman gateway polls Modbus RTU on RS-485 and publishes the readings as JSON over MQTT, so there is no additional converter to buy, power or mount.
Can the gateway also act as a Modbus protocol converter?
The WT460M, the WT600M and the premium CPCB Gateway carry Modbus TCP alongside Modbus RTU, so a single unit can answer your local SCADA over the plant network while it publishes the same readings to the broker. Every other model — including the Ethernet LITE WT610M — polls Modbus RTU on RS-485 and converts it for the uplink; the Ethernet there is the route to your server, not a Modbus TCP port. If you need serial bridged to Ethernet with no cloud role at all, the WE62C converter is the simpler and cheaper answer.
Which MQTT brokers are supported?
Any standard MQTT broker — Mosquitto, HiveMQ, EMQX, ThingsBoard, AWS IoT Core, Azure IoT Hub or your own. You configure the broker address, port, topic, credentials and TLS on the gateway; nothing is locked to a Wiman cloud.
What happens to readings if the network drops?
The gateway stores them and forwards them when the link returns, so the outage becomes a gap that back-fills rather than data you never get. That store-and-forward behaviour is standard across the gateway range.
Which connectivity should I choose?
Use Ethernet where the plant network already reaches the panel — it has the lowest running cost and no SIM. Use 4G/LTE for remote sites with no cabling. Use Wi-Fi for retrofits where cable runs are impractical. Several models combine two, for example the WT460M does Ethernet with 4G failover.