EET3370 – Programmable Logic
Controller Basics
Lab 7 – SLC500 Sequencers
Initial lab written by Rob Gonyer Class of 95
rev.
rev.
PURPOSE
The purpose of this exercise
is to introduce you to the sequencer instruction. The sequencer instruction is one of the most
powerful functions on the PLC. In this
lab, you will program the SQO sequencer output instruction, and will
demonstrate it with the SLC-500.
APPLICABILITY CRITERIA
The functions in this lab
allow you to program sequencing functions used predominantly for machine and
machine line control operations. The
sequencer function is designed to replace, in particular, drum switches, and
therefore can be used in a wide variety of applications.
1. [___] Program the
ladder below. The steps to implement the
sequencer follow the diagram.
| I:1 T4:1 _TON___________________ |
|-----| |----|/|-----------------|Timer
on delay | |
| 0
DN |Timer T4:1 |--EN-|
| |Time Base 0.01 |--DN |
| |Preset 300
| |
| |Accum
0 | |
|
|_______________________| |
|
|
|
|
| T4:1
_SQO___________________ |
|-------|/|----------------------|File #B12:0 |
|
| DN |Mask FFFFh |--EN-|
|
|Destination O:2.0 |--DN |
| |Control R6:1
| |
| |Length 4
| |
| |Position 0
| |
|
|_______________________| |
Please see next page…
SQO Instruction Summary:
File Address: #B12:0
§
This is where
the sequencer reads its data. We will enter
the data later.
File Mask: FFFFh
§
This information
determines which bits will pass through to the output. 1’s or F’s allow data to pass, 0’s do not. You can use any combo, but for purposes we
will use FFFFh (the lower case h stands for
Hexadecimal).
Destination: O:2.0
§
This tells it where
to output the data to. In our case, we
will use the first data word of output slot #2.
Control: R6:1
§
Control file
number. This is the logical address of
the sequencer instruction.
Length: 4
§
You will be
writing 4 words of data, plus there is an initialize word which makes 5 actual
words used.
Position: 0
§
Specifies which
word to start with.
2. [___] Now you will enter the data into the file B12:0.
Open file B12 using project
tree on left side of your screen.
You will then see 5 rows of
binary numbers. You can point and click
around and edit them as you wish. Each
bit corresponds to an output. A 1 is on,
and a 0 is off. The first line will be
your first sequence, the second your second, and so on. Make the bits look like this:
B12:0 0000 0000 0000 0000
B12:1 0000 0000 1111 1111
B12:2 1111
1111 0000 0000
B12:3 1111 1111 1111 1111
B12:4 0000 0000 0000 0000
3. [___] When finished entering the bits, download and run your
program. Watch your outputs after you
turn Input 1 on. After you have seen
that it cycles through this pattern:
a) All lights off
b) 8 lights on
c) Other 8 lights on
d) All lights on
e) Repeat
Demonstrate your program’s
operation to your instructor. Initial
______
4. [___] Now modify your
SQO instruction to alternate between even numbered outputs and odd numbered
outputs. You will need to change your
length to 2, and modify your file content again.
Demonstrate to your instructor.
Initial _________
5. [___] Start a new
program. Build a program that will
emulate a traffic light when input 1 is turned on. To help you along, here are the states and
the time each state is on:
State1 - NS green on, EW red on, 3 sec.
State2 - NS yellow on, EW red on, 1 sec.
State3 - NS red on, EW green on, 4 sec.
State4 - NS red on, EW yellow on, 2 sec.
Repeat
back to state 1.
Use the following addressing
for the lights:
O:2/8 NS Red O:2/12 EW Red
O:2/9 NS Yellow O:2/13 EW
Yellow
O:2/10 NS
Green O:2/14 EW Green
Demonstrate to your
instructor. Initial _______
Print a copy of your traffic
light program and staple it to your lab submission.
DELETE ALL THE FILES YOU
CREATED WHEN YOU ARE FINISHED WITH THIS LAB.