The TC-WPD 2-wire circuit power distribution isolator or TC-WII current input isolator are the complementary products for four-wire instruments of the same kind, with the characteristic that there are only power wire and output current signal wire in series. The signal current is equal to the power supply current, saving two terminal blocks and corresponding wirings due to structural simplicity. Suitable for occasions of small usage amount and small load, this is a practical choice.
But attention should be paid to the following：
As the power supply is not isolated from the output signal, when the usage amount is large, multiple isolators using one ground wire reference point will lead to the signal floating together with the ground potential and grounding error. The method for eliminating this error is to connect output negative electrode of each isolator to the power supply ground wire independently. The error can be reduced to a significant degree. However, ground wires in the panel will be multiplied and the wiring difficulty will be far larger than that of four-wire instrument with the same function.
Although the power distribution voltage is isolated, it still supplied by the power supply. The power distribution voltage is in equivalent series with the output load. Therefore, the two will be limited by the power supply voltage.
A current mutual inductance mode is adopted for two-wire isolation. The signal current cannot be shunted simply by making a parallel connection. Therefore, there is no 1-input and 2-output product model.
The load self-adaptive circuit cannot be added to the output circuit to achieve the purpose of saving electrical energy.
Input signal 4~20 mA; Output signal 4~20 mA.
Accuracy ±0.1% FS; Temperature drift (typical value) <±0.005/℃
Output load is 0-300 Ω and load change error is < ±2 μA/300 Ω.
Power distribution voltage >12 V (when the power supply voltage is > 24 V).
Clamping type structure, with boundary dimension of 12.5×118.5×114.5 (mm).Standard 35 mm DIN guide rail clamping type installation is used.
■ Model, model selection and ordering
Model selection example
Example 1. TC-WPD22-AA……2-input & 2-output，2-wire circuit power distribution isolator（4~20mA input，4~20mA output）
Example 2. TC-WII22-AA……2-input & 2-output， 2-wire circuit current signal isolator（4~20mA input，4~20mA output）
■ Block diagram/wiring diagram
