3 example slc ladder logic program – Rockwell Automation VSM500 Integrated Drive/Motor DeviceNet Option Board User Manual

Page 43

Using I/O Messaging

5-3

5.3

Example SLC Ladder Logic Program

The example program runs the VSM500 unit in the forward and reverse direction. It
also provides a speed reference. Note that the scanner must be in Slot 1 of the SLC
500 rack for this example.

Figure 5.2 – Example SLC Ladder Logic Program

0000

Enable the 1747-SDN Scanner.

This rung clears a fault if the VSM500 unit is faulted.

VSM500 Faulted Bit

I:1

1747-SDN Run Bit

0001

VSM500 Reset fault
Bit

1747-SDN

O:1

1747-SDN

This rung starts the VSM500 unit running forward when either it is not running or if it is at speed and running in reverse.

VSM500 Faulted Bit

VSM500 At Reference

VSM500 Net Control

VSM500 Net Ref

VSM500 Speed
Command

I:1

0002

O:1

1747-SDN

VSM500 Running
Reverse

VSM500 Running
Forward Bit

VSM500 Run
Forward Bit

I:1

1747-SDN

I:1

1747-SDN

VSM500 Run Reverse
Bit

VSM500 Run Forward
Bit

O:1

1747-SDN

I:1

1747-SDN

I:1

1747-SDN

This rung sends a run reverse command to the VSM500 unit when it is running forward and is at speed.

VSM500 Faulted Bit

I:1

0003

O:1

1747-SDN

VSM500 Running
Forward Bit

I:1

1747-SDN

I:1

1747-SDN

O:1

1747-SDN

This rung sets the net reference and net control bits and sends a speed command of 1800 RPM.

0004

O:1

0005

END

1747-SDN

Mov

Move
Source

Dest

1800
1800<
O:1.2
1800<

O:1