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sames

sames

PM4100APD

http://www.sames.co.za

Figure 9: Jumper positions

Module Calibration

The output frequency can be adjusted and calibrated by means

of the variable resistor P1 connected in the voltage divider as

shown in figure 2.

PCB Design Considerations

There are numerous PCB design aspects to consider when

designing a power/energy meter, but only a few crucial aspects

will be discussed here.

The sense resistors on the current input, R2 and R3 must be

located as close to the SAMES device input pins as possible.

This also holds true for the 1MW resistor (R8), and the biasing

resistor R4. Also note that the supply bypass capacitors C2, C3

and C4 (insert C5 and C6 for the SA2002P) must be positioned

as close as possible to the supply pins of the device, and

connected to a solid ground plane.

It is advisable to keep the ground plane surrounding the device

clear of noise that may influence the sensing signals.

The module is protected from high transients on the main

voltage input by means of a Metal Oxide Varistor. These MOVs

will clamp any high transients with a sufficiently long rise time to

neutral, hence protecting the PCB. When designing a meter, a

MOV of type S20 should be used, as the S10 type titled here will

not withstand high surge tests.