Floating-Point Numbers; Strings; Input Relays; Output Relays - Delta AH500 Hardware Operation Manual

5.2.2 Floating-point Numbers

The floating-point numbers are represented by decimal points in ISPSoft. For example, the floating-point
number of 500 is 500.0. Please refer to section 2.2.2 in AH500 Programming Manual for more information.

5.2.3 Strings

What strings can process are ASCII codes. A complete string begins with a start character, and ends with an
ending character (NULL code). If what users enter is a string, they can enter 31 characters at most, and the
ending character 16#00 will be added automatically in ISPSoft. Please refer to section 2.2.3 in AH500
Programming Manual for more information.

5.2.4 Input Relays


Function of the input
The input is connected to the input device (e.g. external devices such as button switches, rotary switches,
number switches, and etc.), and the input signal is read into the PLC. Besides, contact A or contact B of
the input can be used several times in the program, and the ON/OFF state of the input varies with the
ON/OFF state of the input device.

Input number (the decimal number):
For the PLC, the input numbers start from X0.0. The number of inputs varies with the number of inputs on
the digital input/output modules, and the inputs are numbered according to the order in which the digital
input/output modules are connected to the CPU module. The maximum number of inputs on the PLC can
reach up to 8192, and the range is between X0.0 and X511.15.

Input type
The inputs are classified into two types.
1. Regenerated input: Before the program is executed, the data is fed into the PLC according to the
states of the inputs which are regenerated. For example, LD
2. Direct input: During the execution of the instructions, the data is fed into the PLC according to the
states of the inputs. For example, LD

5.2.5 Output Relays


Function of the output
The task of the output is sending the ON/OFF signal to drive the load connected to the output. The load
can be an external signal lamp, a digital display, or an electromagnetic valve. There are three types of
outputs. They are relays, transistors, and TRIACs (AC thyristors). Contact A or contact B of the output can
be used several times in the program, but the output should be used only once in the program. Otherwise,
according the program-scanning principle of the PLC, the state of the output depends on the circuit
connected to the last output in the program.

Output number (the decimal number)
For the PLC, the input numbers start from X0.0. The number of outputs varies with the number of outputs
on the digital input/output modules, and the outputs are numbered according to the order in which the
digital input/output modules are connected to the PLC. The maximum number of outputs on the PLC can
reach up to 8192, and the range is between Y0.0 and Y511.15.
The output which is not practically put to use can be used as a general device.

Output type
The outputs are classified into two types.
1. Regenerated output: Not until the program executes the instruction END is the information fed out
according to the states of the outputs. For example, OUT Y0.0.
2. Direct output: When the instructions are executed, the information is fed out according to the states
of the outputs. For example, OUT DY0.0.
C h a p t e r 5 D e vi c e s a n d A s s i g n i n g A d d r e s s e s
X0.0.
DX0.0.
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