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sames

RM2102DSE

http://www.sames.co.za

PRELIMINARY

The connections are made as is shown in figure 4. Also see

Table 1.

The optical-isolated pulse output is taken to the + and -

terminals on the meter-box.

A mechanical counter can also be connected to J21 on the

PCB in place of the stepper motor counter that is currently

connected to J20 on the PCB.

Please take note that the meter is referenced to live, and care

must be taken when connecting test equipment to the meter.

The PM2102DP meter is equipped with several solderable

selectors , which will allow the user / meter manufacturer to set

the meter up to their own specifications. Table 2 describes the

various jumper options. This table should be used in

conjunction with figure 5, which will make it easier to locate the

jumper in question.

1

Figure 5: Solderable selector positions and default setup.

This default setup enables fast mode output, with the pulse

stability circuitry enabled, for the measurement of bi-

directional

DESIGN EXAMPLES

Selection Of R1, R2 And R0 For Different Rated Conditions

DF_LED

DF_MO

Please note that the MOTOR and PULSE outputs are

related to each other, thus changing the one will change

the other.

The following equations and tables state the basic pulse

constants and motor constants obtainable with the PM2102DP

meter.

The Output pulse equation is:

LED p/kWh =

1160p/sec x (1/DF_LED) x [3600 / ((Vnom x IMAX) / 1000)]

And the motor constant equation is:

MOTOR p/kWh = LED p/kWh / DF MO

where dividing factors

and

are described in

Table 3 (R2, R1 and R0 are input pins for SA2102D).

Example 1

Rated voltage:

220V

Rated current:

80A

Sensing element: SHUNT (80A, 50mV, 625µ )

Pulse constant:

800 imp/kWh

Motor constant:

100 imp/kWh

Calculate R15 and R16:

R15 = R16

= (I / 16µA) x R

/ 2

= 80A / 16µA x 625µ

/ 2.

= 1.5625 k

A standard value of 1k6 is chosen.

The pulse constant is derived from the equation below:

LED p/kWh = 1160p/sec x (1 / DF_LED) x [3600/((Vnom x

Imax)/1000)]

= 1160 p/sec x (1 / DF_LED) x [3600 / (220 x 80) /

1000]

800 = 1160 p/sec x (1 / DF_LED ) x 204.54

1 / DF_LED = 0.0033717

DF_LED = 296

MOTOR p/kWh = LED p/kWh / DF_MO

100 = 800 / DF_MO

DF_MO = 8

W

LSH

W

W

Table 1: External connector descriptions

Name

Function Description

Live Current In

Neutral Current Out

Live

Neutral

Optical-isolated output. Connect to

measurement equipment

1

2

3

4

+ and -

Notes

Solderable selectors are two pads that can be connected together by means of solder to act as a jumper.

SA2102D

J22

J11

J19

J3

C8

J4

J5

J6

J7

CNF FAST

MAINS

J1

DIRO/DIRI

SHUNT

J2

SAMES

R0

R1

R2

SO

VDD

VDD

VSS

VSS