Single-End Output Circuit - FATEK M Series User Manual

6-2 Single-End Output Circuit M-Series
M-Series PLC output circuits such as relays, transistors or TRIAC are single-end output structure. A
single-end output in each digital output (DO) takes up only one terminal. But since any output device has
two ends, the one end of several output devices has to be connected together to one common point (called
output common) for single-end output. Then each output point can output via this common point. The
more output device shares same common points, the more terminals are saved, while relatively increasing
the current running through the common point. Combination of any output common with its individual
single-end outputs are called a Common Output Block. The various single-end common output circuits are
described below：
6-2-1 Structure and Wiring of Single-End Relay Output Circuit
Because relay contacts have no polarity, it can be applied for AC or DC load power. Each relay can
provide current up to 2A. The maximum rated current in all output commons of M Series PLC is 8A. Its
mechanical lifetime can reach up to 2 million times, while the contacts have a shorter lifetime. The lifetime
also varies depending on working voltage, load type (power factor cosψ) and contact current. The relation
between them is plotted in the figure below. In the case of pure resistive load (cosψ=1.0) at 120VAC and
2A, the lifetime of contacts is about 250 thousand times. While for high inductive or capacitive load with
cosψup to 0.2 and current within 1A, the lifetime decreases rapidly to about 50 thousand times (AC200V)
or 80 thousand times (AC120V).
Single-End Relay Output Circuit
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Single-End Relay Output Circuit
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M-Series PLC Expansion Module User Manual
Chapter 6 Digital Output Circuit