Signal output - WAT12

WAT12 User Guide

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User guide

The signal output provides 2 analog current loops, direction and speed, with sourcing drivers with an o/p driving voltage 10.5 V typically and an o/p resistance of 57 W. The loops return to the common ground for power and signal. The signal and sensor power outputs are also current limited.

Typically, only a 4-wire shielded cable is required for the line between WAT12 and the receiving end. Two of the 4 wires provide the operating power for the system. The other 2 are for the current source outputs from the WAT12 transmitter; one delivering the speed signal and the other the direction signal. The 2 readout devices are wired each across the respective current source terminal (+) and the negative terminal of the power supply (-).

For a typical system with a 24 V DC power supply and the 5 mA signal currents, see the following figure.

Figure 1. Typical system with 24 V DC power supply and 5 mA signal currents

The following figure shows wiring for high-noise environment. Make sure that you also ground the cable at the power supply.

Figure 2. Wiring for high-noise environment

The following figure shows wiring for long distance with the 5 mA loop current. Pay attention to the maximum resistance values for both the power and signal leads.

Figure 3. Long distance wiring

The following figure shows 4-wire wiring for long distance with a 48 V DC power supply.


A source resistance, over 1000 Ω, must be used for dropping VIN to an acceptable level, because if VIN exceeds 28 V DC, the transmitter may be damaged permanently.

Figure 4. Long distance wiring with 4 wires