NEWDOSE Metering Pump Wiring: DP Pulse and DM 4-20mA Inputs

NEWDOSE metering pump wiring comes down to two circuits: a 220 VAC, 50 Hz supply, and one control input that depends on the model. The DP series counts external pulses, the DM series follows a 0/4-20mA current signal, and both have a separate remote control port for a dry-contact start/stop. This guide is for panel builders and site electricians connecting a NEWDOSE solenoid diaphragm pump to a PLC or flow meter.

Which NEWDOSE model are you wiring?

The first block of the model code tells you the control mode. DFD is manual, set from the keypad, with only a remote control port. DP takes external pulses. DM takes a standard 0/4-20mA signal. DC talks RS485. The mistake we see most on retrofit jobs is a drawing that simply says "external control", a DP pump ordered against it, and a PLC that only has analog outputs. Check the nameplate before you plan any NEWDOSE metering pump wiring.

A solenoid pump delivers a fixed volume per stroke, so its flow is set by stroke rate, the number of strokes per minute. Pulse control and current control are just two ways of telling the pump how fast to stroke.

NEWDOSE metering pump wiring: the power circuit

Every NEWDOSE metering pump wiring job starts with the supply. The pump ships with roughly 1.5 m of power cable, which you can extend. Follow the cable colors shown in the manual. Fit a miniature circuit breaker between the pump and the supply and install to local electrical code.

Isolate the supply before touching any connector. Plugging or unplugging signal connectors live is a common way to damage the control board. The pump housing is IP55, so on a wash-down floor route cable glands downward and keep water from running along the cable into the connector.

DP pulse input: NEWDOSE metering pump wiring for meters and PLCs

The DP series has two control ports:

1. Remote control port: a dry-contact switch input, configurable as normally open or normally closed, used for remote start/stop.
2. Pulse control port: accepts a pulse signal or a voltage-free switch signal. Pulse voltage must not exceed 24 V.

Connections are made through a circular connector with a shell, plug and socket, and each solder terminal is numbered. Which pin is positive and which is negative is shown on the wiring diagram in the manual for that model; follow it rather than habits from another brand.

Typical pulse sources are a pulse-output water meter or a PLC transistor output. A 24 V active pulse sits right at the limit, so anything higher needs an isolator.

Setting the DP pulse ratio

Press A/M to switch modes. The display shows H for manual and P for external pulse control. The manual is clear that you can only change mode while the pump is stopped, so A/M doing nothing during a run is not a fault.

To finish NEWDOSE metering pump wiring on a DP, set the ratio: press on/off, then hold ADJ. You can edit the number of output strokes and the number of control pulses, which sets how many strokes the pump makes for a given number of incoming pulses. Dense meter pulses call for division; sparse pulses call for multiplication. The right ratio depends on the meter's pulse value and your target dose, so start from the calculated figure and then check it with a calibration cylinder. The DP-LM variant displays differently; follow its manual.

NEWDOSE metering pump wiring for DM 4-20mA: polarity first

The DM series also has two ports: the remote control dry contact and a current control port for 0/4-20mA. The pump changes its stroke rate in proportion to the current, and the proportional factor is adjustable.

Never reverse the signal polarity. The manual warns that reversed signal wires can destroy the control board or the whole pump, and the maker may refuse warranty. In most NEWDOSE metering pump wiring, the current comes from a PLC analog output card or a pH controller's transmitter output. Check polarity with a meter before you land the wires.

The four DM set points in NEWDOSE metering pump wiring

In auto mode the display reads 000A; a flashing A means stopped, steady means running. Hold ADJ for about 5 seconds to open the parameters:

• Parameter 1, start current: below this current the pump stops.
• Parameter 2, end current: between start and end current the pump calculates its stroke rate from the signal.
• Parameters 3 and 4, start and end frequency: the stroke rates matched to each end of the current range.

If the start frequency is lower than the end frequency, control is direct acting; if it is higher, control is reverse acting. When a pH loop slows the pump as pH drifts further away, the wiring is usually fine and parameters 3 and 4 are simply swapped. Good NEWDOSE metering pump wiring can still behave badly with the wrong set points.

Remote port interlocks in NEWDOSE metering pump wiring

Many installers wire only the pulse or the current input and leave the remote port empty. On the panel drawing in the manual, that port is marked as not drilled as standard, so ask for it when you order. It is the right place for interlocks: low tank level, no flow in the main line, or an emergency stop.

Stopping the pump by dropping the analog signal to zero is less reliable. With 4-20mA, a broken wire reads 0 mA and the pump stops on the start current rule, which is fail-safe. Set the start current to zero, though, and broken-wire behavior depends on your parameters. Keep interlocks on the dry contact and let the analog signal handle speed.

Commissioning order for NEWDOSE metering pump wiring

Run the pump in manual first. Press Start/Stop, confirm the red LED flashes at the displayed rate and that chemical reaches the discharge. Then switch to P or A, have the PLC send a fixed signal, and time the output into a cylinder for a few minutes. Flow is roughly maximum flow divided by full stroke rate, times the current stroke rate; full rate is 120 or 160 strokes per minute depending on the model, so read the nameplate. Back pressure changes real output, so calibrate on site. Add a low-level switch on the tank; our guide on dosing pump low level alarm setup covers the wiring and delay.

Conclusion

Correct NEWDOSE metering pump wiring means a dedicated breaker, power isolated while you work, DP pulses kept at or below 24 V with the stroke ratio set on the keypad, and DM current wired with the right polarity and four set points that define direct or reverse action. Pin numbers should be taken from the manual for your model. If you are still choosing between control types, read DFD manual vs DP pulse control and 4-20mA vs pulse control, then browse our solenoid metering pumps or the NEWDOSE brand page. Send us your signal type, flow and pressure and contact our engineers to check the wiring plan.

FAQ

Can a DP pump take a PLC relay output?

Yes. A relay contact is a voltage-free switch signal, which the pulse port accepts. At high pulse rates a relay may not keep up, so a transistor output is the better choice.

Why does my DM pump not run at 4 mA?

The start current is probably set above 4 mA. Below the start current the pump stops, so lower parameter 1 and test again.

Should the remote stop be normally open or normally closed?

Either works. If you want the pump to stop when the cable is cut, use normally closed.

Can signal cable share conduit with power cable?

It is not recommended. For NEWDOSE metering pump wiring, run pulse and current signals in separate conduit or shielded cable, grounding the shield at one end only.

Where do I find the terminal numbers for NEWDOSE metering pump wiring?

On the wiring diagram in the instruction manual, and on the numbered solder terminals inside the connector. Follow the manual for your exact model.