sames

sames

SA2005P

8/16

http://www.sames.co.za

Figure 7: Signal flow block diagram

DEVICE CONFIGURATION

SIGNAL FLOW DESCRIPTION

The following is an overview of the SA2005P’s registers. For a

detailed description of each parameter please refer to

parameter description section. Figure 7 shows the various

registers in the SA2005P’s power to pulse rate block. The

inputs to this block are three single bit pulse density modulated

signals, each having a pulse rate of 641454 pulses per second

at rated conditions. The parameters Cb1, Cb2, Cb3, Sum, Ct,

Kr, CresH, CresL, Cled and Pw contain values that are read

from the external EEPROM during power up.

The Pre-Divider registers are used for calibration and to

balance the gain of each channel. The Programmable Adder is

used to select between the total sum or absolute sum of the

measured energy. The Creep current threshold detector

selects the creep current which is relative to the meters rated

current. The Rated Condition register is used to program the

rated condition of the meter and feeds the registers LED-

constant and Counter Resolution with the applicable pulse

rate. These two registers are programmed to select the LED

output rate and the counter resolution (pulses per kWh)

respectively. The Counter Pulse Width register is used to

program the pulse width for the mechanical counter driver

output MOP and MON.

EEPROM Memory Allocation

The following table shows the EEPROM memory allocation as

well as the corresponding name. The uneven byte always

Pre-Divider

÷Cb1

Pre-Divider

÷Cb2

Pre-Divider

÷Cb3

Programmable Adder SUM

Creep current threshold detector

Ct

Rated Condition

÷Kr

Counter

Resolution

CresH, CresL

LED-Constant

Cled

Counter Pulse

width

Pw

MOP

MON

LED

Normally 6400p/kWh

Normally 1253p/s

Power from

converters

641454 pulses/s

S - D

Power from

converters

641454 pulses/s

S - D

Power from

converters

641454 pulses/s

S - D

Description

2

E Address

Contents

Bit [7:0]

Name

Channel Balance 3

Channel Balance 1

Channel Balance 2

Summing mode

Rated Condition

Led Pulse-rate

Counter Resolution (LSB)

Counter Resolution (MSB)

Counter Pulse-Width

10

11

12

13

14

15

16

16

17

20

21

22

23

24

25

26

26

27

Cb3

XOR of ADDR 10

Cb1

XOR of ADDR 12

Cb2

XOR of ADDR 14

SUM

Ct

XOR of ADDR 16

Kr

XOR of ADDR 20

Cled

XOR of ADDR 22

CresL

XOR of ADDR 24

ClresH

Pw

XOR of ADDR 26

---v vvvv

xxxx xxxx

---v vvvv

xxxx xxxx

---v vvvv

xxxx xxxx

---- --vv

v--- ----

xxxx xxxx

vvvv vvvv

xxxx xxxx

---- --vv

xxxx xxxx

vvvv vvvv

xxxx xxxx

---v vvvv

vv-- ----

xxxx xxxx

D10

D12

D13

D16

D16

D20

D22

D24

D26

D26

KEY: (- = DON’T CARE); (V = VALUE/PARAMETER); (0,1 = LOGICAL VALUE); (X = BIT-XOR)

Creep current threshold

contains a XORed byte of the previous even byte. This is the

checksum byte used by the SA2005P to ensure data integrity.