2-17
Section
Differential Monitor
159
2-16-1 Definition of Signed Binary Data
Signed binary data is manipulated using 2’s complements and bit 15 is used as
the sign bit. The range of data that can be expressed using one word is as fol-
lows:–32,768 to 32,767 (8000 to 7FFF hexadecimal).
The following table shows equivalents between decimal and hexadecimal data.
Decimal
4-digit Hexadecimal
32,767
32,766
.
.
.
2
1
0
–1
–2
.
.
.
–32,767
–32,768
7FFF
7FFE
.
.
.
0002
0001
0000
FFFF
FFFE
.
.
.
8001
8000
2-16-2 Arithmetic Flags
The results of executing signed binary instructions is reflected in the arithmetic
flags. The flags and the conditions under which it will turn ON are given in the
following table. The flags will be OFF when these conditions are not met.
Flag
ON conditions
Carry Flag (SR 25504)
Carry in an addition.
Negative results for subtraction.
Equals Flag (SR 25506)
The results of addition, subtraction,
multiplication, or division is 0.
Results of converting 2’s complement is 0.
2-16-3 Inputting Signed Binary Data Using Decimal Values
Although calculations for signed binary data use hexadecimal expressions, in-
puts from the Programming Console or SSS can be done using decimal inputs
and mnemonics for the instructions. The procedure to using the Programming
Console to input using decimal values is shown in the
CPM1 Operation Manual,
CPM1A Operation Manual,
CPM2A Operation Manual,
CPM2C Operation
Manual
,
and
SRM1 Master Control Unit Operation Manual
. Refer to the
SSS Op-
eration Manual: C-series PCs
for details on using the SSS.
Inputting Instructions
Refer to the
CPM1 Operation Manual, CPM1A Operation Manual,
CPM2C Op-
eration Manual,
CPM2A Operation Manual
,
and
SRM1 Master Control Unit Op-
eration Manual
details on inputting instructions from the Programming Console.
2-17 Differential Monitor
The CPM1/CPM1A, CPM2A//CPM2C, and SRM1(-V2) support differential
monitoring from either the Programming Console or the SSS. The operator can
detect on OFF-to-ON or ON-to-OFF transition in a specified bit. When the speci-
fied transition takes place, the transition is indicated on the display and a buzzer
sounds to enable easy recognition of the transition.
Refer to the
CPM1 Operation Manual, CPM1A Operation Manual, CPM2A Op-
eration Manual,
CPM2C Operation Manual,
or
SRM1 Master Control Units Op-
eration Manual
for details on the Programming Console Differential Monitor pro-
cedure and to the
SSS Operation Manual: C-series PCs
for the SYSMAC Sup-
port Software procedure.