16
SIGNED INTEGER
Signed Integers are 16-bit values transmitted as two 8-bit bytes. The most signifi-
cant byte is always transmitted first. These values vary in the range -32767 to
+32767 although some registers have a limited range of acceptable values. The
most significant bit defines the sign, zero indication positives.
UNSIGNED INTEGER
Unsigned Integers are 16-bit values transmitted as two 8-bit bytes. The most
significant byte is always transmitted first. These values vary in the range 0 to
65535, although some registers have a limited range of acceptable values.
UNSIGNED LONG INTEGERS (Unsigned Long)
Unsigned long integers are 32-bit values transmitted as four 8-bit bytes. The most
significant byte is always transmitted first. These values vary in the range 0 to
4294967295, although energy registers in the GIMA have a limited range: 0 to
999999.
4.5.1 Table 2 Accumulated Energy Readings
4.5.1.1 Energy Registers
Energy registers available for display on a GIMA are stored in Modbus Table 2 as
unsigned long integers. Registers not available on an individual meter are re-
turned as zero.
t
e
s
ff
O
s
s
e
r
d
d
A
s
t
n
e
t
n
o
C
t
a
m
r
o
F
s
e
t
y
B
s
d
r
o
W
s
s
e
c
c
A
0
2
1
5
i
H
e
l
a
c
S
y
g
r
e
n
E
g
n
o
L
d
e
n
g
i
s
n
U
4
2
y
l
n
O
d
a
e
R
1
3
1
5
o
L
e
l
a
c
S
y
g
r
e
n
E
2
4
1
5
i
H
h
W
k
g
n
o
L
d
e
n
g
i
s
n
U
4
2
e
ti
r
W
/
d
a
e
R
3
5
1
5
o
L
h
W
k
4
6
1
5
i
H
h
A
V
k
g
n
o
L
d
e
n
g
i
s
n
U
4
2
e
ti
r
W
/
d
a
e
R
5
7
1
5
o
L
h
A
V
k
6
8
1
5
i
H
)
d
n
I
(
h
r
a
v
k
g
n
o
L
d
e
n
g
i
s
n
U
4
2
e
ti
r
W
/
d
a
e
R
7
9
1
5
o
L
)
d
n
I
(
h
r
a
v
k
8
0
2
5
i
H
)
p
a
C
(
h
r
a
v
k
g
n
o
L
d
e
n
g
i
s
n
U
4
2
e
ti
r
W
/
d
a
e
R
9
1
2
5
o
L
)
p
a
C
(
h
r
a
v
K
17
4.5.1.2 Writing to Energy Registers
Function 6 or 16 may be used to write to the energy registers in Table 2. Function
6 allows access to the upper and lower integers of the 4-byte long individually.
Upper integers have a maximum write value of 0x00F, preventing out-of-range
data from being sent to the GIMA.
Function 16 may be used to access a number of long integers using a single
command. This is most useful for setting all registers to 0 simultaneously. Valid
commands must send an even number of integers (2 integers per long) starting at
an even address in Table 2 (start of a register). Failure to follow these basic rules
will result in an exception response (ref. section 4.5.12).
4.5.1.3 Energy Scaling
Energy readings from the GIMA are stored as unsigned long integer values with
no decimal point of legends (e.g. kWh or MWh). A single scaling factor is provided
to enable conversion of the raw data to real numbers in basic unit form (Wh, Vah or
varh). The scaling factor is a constant value calculated in the GIMA as a function
of CT and PT Primary programming. To convert raw data to real numbers:
E = L x 10
(K-3)
Where:
L
= Long Integer number
K
= Energy Scaling Factor
E
= Scaled Energy Result
Example:
If the meter is programmed with CT Primary = 50A, and PT Primary = 415V, the
meter displays would be 99999.9 kWh, 99999.9 kVAh and 99999.9 kvarh. The
Energy Scaling Factor would be transmitted as 999999.
Wh would be calculated at 999999 x 10
(5-3)
= 999999 x 100 = 99999900Wh
VAh would be calculated at 999999 x 10
(5-3)
= 999999 x 100 = 99999900VAh
varh would be calculated at 999999 x 10
(5-3)
= 999999 x 100 = 99999900varh