Skip to main content

Home › Applications › Tank, pump & flow monitoring

Tank, Pump & Flow MonitoringLevel, flow and pump state from unmanned water sites — and the pump switched when the level says so

A level transmitter on the 4–20 mA input, a flow meter on Modbus or a pulse input, the pump's run contact on a digital input. The gateway reports all of them, texts the operator when the level crosses your set points, and can switch the starter through its relay — at a pump house with nobody in it, and with no server in the loop.

  • 4–20 mA level
  • Flow by Modbus or pulse
  • Set-point SMS
  • Relay to the starter
  • Works through outages
Talk to our engineersWT400M 4G gateway
01

Watch it work

click a step to hold it
4–20 mA · RS-485 · relay4G · MQTT + SMSLevel transmitter4–20 mA inputLevel 64%Level 41%Level 18% · LOWLevel 18%Level 91% · HIGHFlow meterModbus RTU · slave 112.6 m³/h12.4 m³/h18.2 m³/hPressure (WT36i)4–20 mA via IO cardPump starterRelay → interposerRelay ON · runningRelay OFF · stoppedWater dashboardServer · MQTTOperator phoneSMS · 4G modelsWiman gatewayEdge triggers · relayTrigger: level < 20%Relay ONTrigger: level > 90%4–20 mA · RS-485 · relay4G · MQTT + SMSLevel transmitter4–20 mA inputLevel 64%Level 41%Level 18% · LOWLevel 18%Level 91% · HIGHFlow meterModbus RTU · slave 112.6 m³/h12.4 m³/h18.2 m³/hPressure (WT36i)4–20 mA via IO cardPump starterRelay → interposerRelay ON · runningRelay OFF · stoppedWater dashboardServer · MQTTOperator phoneSMS · 4G modelsWiman gatewayEdge triggers · relayTrigger: level < 20%Relay ONTrigger: level > 90%
  1. Step 1 of 5The gateway reads the tank level on its own 4–20 mA input, and the flow meter and pressure card on the RS-485 line.
  2. Step 2 of 5On the log interval the readings go to the dashboard — level, flow, pressure and the pump's state in one packet.
  3. Step 3 of 5The level falls below the low set point. A trigger fires once on that crossing and texts the operator from the gateway's own SIM.
  4. Step 4 of 5A second trigger on the same crossing switches the gateway's relay ON. It drives the starter's interposing relay; the starter's own protections stay in charge.
  5. Step 5 of 5Flow rises and the tank fills. At the high set point another trigger switches the relay OFF — and every step was logged and sent, even through a network drop.
02

What connects to the gateway

EquipmentHow it connectsWhat the gateway reads
Level transmitter (ultrasonic, hydrostatic, radar)4–20 mA · gateway inputTank or sump level; the WT400M has two 4–20 mA channels, the IO cards add more
Electromagnetic or ultrasonic flow meterRS-485 · Modbus RTUFlow rate and totaliser, from the meter's register map
Flow or water meter with a pulse outputPulse into a gateway inputVolume by pulse count and the present rate
Pressure transmitter, extra levels4–20 mA · WT36i card on RS-485Up to six 4–20 mA and six 0–10 V signals per card
Pump starterRun contact → DI · relay → interposing relayRunning or stopped; the gateway's relay asks the starter to start or stop
Panel door, float switchDigital inputOpen / closed, full / not full — each change can raise an SMS
03

What the gateway does here

Edge triggerActs on the level by itselfRules compare a reading with your set point: below the low mark, above the high mark, inside or outside a band. Each fires once per crossing — on the gateway, with no server in between.
RelayStart on low, stop on highOne rule switches the relay ON, another switches it OFF. With a gap between the two limits the pump does not start and stop all day.
SMSTexts from the gateway's SIMLow level, high pressure, a panel door opening — each firing texts up to five numbers, with the live value and the time in the message (4G models).
Modbus writeOr write to the starter's controllerWhere the pump panel has a Modbus controller, a trigger can write its run register instead of switching the relay.
Store & forwardHistory with no holesReadings logged while the network is down go out oldest first, with their own time stamps, when it returns.
Pulse & run hoursVolume and pumping hoursPulse-rated inputs totalise a meter's pulses; on the WT460M the configurable inputs clock how long the pump has run.
04

Which gateway fits

open a model for its full specification
PRO · 4GWT400MTwo 4–20 mA inputs, a relay, edge triggers and SMS — the pump house in one box.View the WT400M →MAX · 4G + LANWT460MFor treatment plants with a LAN: Ethernet first, 4G when it drops, triggers and SMS on both.View the WT460M →IO cardWT36iSix 4–20 mA and six 0–10 V inputs plus a relay, on the gateway's RS-485 line.View the WT36i →LITE · 4GWT410DMMonitoring only: level on 4–20 mA and a Modbus flow meter, to one server. No relay or triggers.View the WT410DM →
05

Being straight about it

Control, not protectionDry-run, overload and phase-failure protection stay in the starter and the pump's own relays. The gateway asks for a start or a stop; it does not replace a protection device.
Drive a coil, never the motorThe gateway's relay drives an interposing relay or contactor with a low-voltage DC coil — never a motor, a mains load or a mains coil directly.
Two set points, with a gapStart on low and stop on high, with a band between them. A single limit with no gap makes a pump hunt around it.
SMS travels at the network's paceThe text is built about two seconds after the crossing; the mobile network adds its own delay — usually seconds, sometimes minutes.
06

Questions

Can the gateway start and stop the pump on its own?

Yes, on the PRO and MAX series. One trigger switches the relay ON when the level falls below the low set point and another switches it OFF above the high set point. The rules run on the gateway, so they keep working when the server or the network is down. The relay drives the starter's interposing relay; the starter's own protections stay in charge.

Which level sensors work with it?

Two-wire 4–20 mA level transmitters — ultrasonic, hydrostatic or radar — on the gateway's 4–20 mA input. The WT400M has two channels; a WT36i card on the RS-485 line adds six more. Modbus RTU level sensors work on the RS-485 line too.

Can it read my flow meter?

Yes: a flow meter with a Modbus RTU output and a published register map is polled on the RS-485 line; a meter with a pulse output wires to a pulse-rated input, which totalises the pulses and reports the rate.

Will I get an SMS when the tank runs low?

Yes, on the 4G PRO and MAX models (WT400M, WT460M). Each firing sends one SMS to every number filled in — up to five — with the live value and the time in it. A daily SMS limit keeps a faulty sensor from emptying the SIM's balance.

What happens when the mobile network is down?

The triggers run on the gateway, so the pump is still switched at your set points. Readings are logged and back-filled to the server, oldest first, when the network returns.

Can I check and switch the pump from my phone?

The dashboard on your server shows the readings. Commands can be sent to the gateway from the server, or as an SMS command protected by the gateway's SMS password on the 4G models.

How a 4–20 mA loop worksPulse counting & run hoursHow store & forward worksIO cards for more inputs
Tell us the site, the equipment and the server.We will tell you which gateway fits, and configure it before it ships.
Send an enquiry →