Delta Electronics VFD-E manual Example 3 the latching circuit of SET and RST commands

Appendix D How to Use PLC Function

Example 3: the latching circuit of SET and RST commands

The figure at the right side is latching circuit that made up of RST and SET command.

It is top priority of stop when RST command is set behind SET command. When executing PLC from up to down, The coil Y1 is ON and coil Y1 will be OFF when X1 and X2 act at the same time, therefore it calls priority of stop.

It is top priority of start when SET command is set after RST command. When X1 and X2 act at the same time, Y1 is ON so it calls top priority of start.

„The common control circuit

Top priority of stop X1

X2

Top priority of start X2

X1

SET Y1

RST Y1

RST Y1

SET Y1

Example 4: condition control

X1

Y1

X2

Y2

X3

Y1X1

X3

X2

X4 Y1

Y2X4

Y1

Y2

X1 and X3 can start/stop Y1 separately, X2 and X4 can start/stop Y2 separately and they are all self latched circuit. Y1 is an element for Y2 to do AND function due to the normally open contact connects to Y2 in series. Therefore, Y1 is the input of Y2 and Y2 is also the input of Y1.

Revision June 2008, 04EE, SW--PW V1.11/CTL V2.11 D-15