Output Relays; Auxiliary Relays; Special Auxiliary Relays; Stepping Relays - Delta Electronics AH500 Operation Manual

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.

5.2.6 Auxiliary Relays

The auxiliary relay has contact A and contact B. It can be used several times in the program. Users can
combine the control loops by means of the auxiliary relay, but can not drive the external load by means of the
auxiliary relay. The auxiliary relays can be divided into two types according to their attributes.
1. For general use: If an electric power cut occurs when the PLC is running, the auxiliary relay for
general use will be reset to OFF. When the power supply is restored, the auxiliary
relay for general use is still OFF.
2. For latched use: If an electric power cut occurs when the PLC is running, the state of the auxiliary
relay for latched use will be retained. When the power supply is restored, the state
remains the same as that before the power electric cut.

5.2.7 Special Auxiliary Relays

Every special auxiliary relay has its specific function. Please refer to section 2.2.7 in AH500 Programming
Manual for more information.

5.2.8 Stepping Relays

Function of the stepping relay:
The stepping relay can be easily used in the industrial automation to set the procedure. It is the most basic
device in the sequential function chart (SFC). Please refer to ISPSoft User Manual for more information related
to sequential function charts.
There are 2048 stepping relays, i.e. S0~S2047. Every stepping relay is like an output relay in that it has an
output coil, contact A, and contact B. It can be used several times in the program, but it can not directly drive
X0.0.
DX0.0.
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