Beckwith Electric M-2025D Current Loop Interface Module

Current‑to‑Voltage Analog Converter used with the M‑2001 Series Digital

Tapchanger Controls and M‑2948 Tap Position Sensors to provide positive

tap position knowledge

• Includes dual functionality to convert current loop outputs from INCON®

1250 series to voltage signals for M-2001 Series Tapchanger Controls and

accepts direct current inputs from Beckwith Electric M-2948 Tap Position

Sensors

• Beckwith Electric Tap Position Sensors directly mechanically replace

Selsyn Type tap position sensors

• Connects easily to the M-2001 Series Digital Tapchanger Control using

an included 3-foot 6-pin connector cable

• Provides a 9-position terminal block for easy connections

• Enclosed components permit user to select one of four current range

configurations

• Small size permits mounting on any flat surface at least 6-1/2" wide

and 2-5/8" high

The M-2025D Current Loop Interface Module is a current-to-voltage analog

converter that accepts a standard 4-20. 0-1. 0-2 or ± 1 mA input or inputs

from the Beckwith Electric M-2948 Tap Position Sensor.

Beckwith Electric Tap Position Sensors are absolute position indicators that

directly mechanically replace an INCON Position Transducer. The Beckwith

Electric Tap Position Sensors provide a 4-20 mA dc current loop output.

The lowest current value corresponds to the lowest tap number. The highest

current value corresponds to the highest tap number. The current signals are

converted to a voltage signal using a shunt resistor (see Table 2) on the

voltage input to the M-2025D. The resultant voltage signal is conditioned in

the M-2025D and routed to the M-2001 series Tapchanger Control where the

voltage is converted to a corresponding tap position number.

M‑2025D Current Loop Interface Module Applications

Beckwith Electric M‑2001B, M‑2001C and M‑2001D Digital Tapchanger

Controls: The M-2025D Current Loop Interface Module connects to the control

through the included 3-foot B-0753 interface (6 pin to 6 pin) cable.

The control provides low-voltage dc to power the M-2025D and accepts an

analog voltage input as described above. The M-2001 control includes a tap

calibration screen to establish a reference tap position and it allows the current

tap position to be viewed. The B-0753 interface cable is optionally available in

6-ft (B-0753-01), 8-ft (B-0753-02), 12-ft (B-0753-03), 15-ft (B-0753-04), and

25-ft (B-0753-25) lengths and should be ordered as a separate line item if the

included 3-foot length is too short.

Beckwith Electric M‑2001. M‑2001A or M‑2001A‑1 Tapchanger Control: The

M-2025D Current Loop Interface Module connects to the M-2001. M-2001A,

or M-2001A-1 through the B-0752 interface cable (5 pins on one end and 6

pins on the other end). These controls provide low-voltage dc to power the

M-2025D, and accept an analog voltage input as described above.

They also include a tap calibration screen to establish a reference tap position

and it allows the current tap position to be viewed.

Incon 1250 Series Rotary Position Indicator

Another configuration commonly encountered is the Selsyn position indicator

(Figure 2). These tap position sensors are traditionally used with a Tap Position

Monitoring device such as the Incon 1250 series devices.

The Selsyn encoder is an electromagnetic device that resembles a small electric

 motor. Although using various configurations of internal windings, they typically

excite rotor winding(s), and induce AC signal voltages in the stator windings

which can be compared in amplitude and polarity to determine the angular

position of the rotor shaft.

The Tap Position Monitor generates the voltage signals supplied to the rotor

winding(s). It then measures the resulting signals from the stator winding to

determine the shaft's rotational position. This informationis converted to a

tap number and displayed on the front panel numeric readout. An analog

current signal is also generated which corresponds to tap position.

The M-2025D Current Loop Interface module accepts this analog current