DP2520 Lab Exam1
RTO-Timers, Counters
Name:
Student ID:
Due Date: by the end of the lab of week March 7th
How to submit:
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Submit 2 electronic file(s) in .ACD and word format ON D2L ONLY
Save your file with the following name format: LabExam1_ student names
You can work remotely or in person wearing full PPE (Mask & SHIELD), in groups of 2 or 3 and
submit ONE file
Do not delete the instruction
In case members of the group do not share the activity equally, the mark of the members will be
different.
Use rung comments to document the purpose of the rung or section of rungs, the purpose of
specific contacts within the rung (specific instructions), to review the operation of your program
at a later date.
Explain your work at in the report
Note: All your activity should be verified by the instructor before submitted into D2L
Mixing Tank
Write a ladder program for a batch mixer, shown in figure below, to do the
followings.
Material A and material B are pumped in a tank of 5 meters, so level is 5m. The
two material are to be mixed and heated up to 100oC. A timer measures the
amount of time the heater has been running per day which needs to be reset
either manually or if the heater has worked more than 20 hours in a day. After
the mixture is heated up sufficiently and the tank is full, the mixture should be
drained. A drain flag should turn on (latched) so that the mixed product be
drained out through until an empty sensor turns on in order to indicate that the
whole product has been drained (unlatches the drain flag). This process should
repeat automatically after the end of each cycle.
Note:
 Create base tags for all the instructions
 enter the preset of the timers you use in seconds, NOT in milliseconds,
for the sake of time in the lab
 Tips for programming the Batch Mixer (note that these are only suggestions, you can implement
differently as long as the logic is correct)
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Run Mode Section
Rung 0 - Start/Stop Station- Seal In the start with a run indicator – process should not stop until the
product is emptied so seal in the stop with the drain process (e.g. drain flag)
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Level Tracking Section
Level of the Solution A is measured by a Counter Set To 5 Units
Level of the Solution B is measured by a Counter Set To 5 Units
After both levels are reached, set a full tank flag on (DN bits in series)
Stop pump1 & 2 after tank is full. Pumps also need to remain closed during the drainage
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Heater and mixer section
Heater should be on during the filling process
Heater should turn off when:
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temperature reaches 100oC (you can use a switch to indicate that the temperature has reached its
set point)
heater also needs to be controlled by empty sensor which means that when the tank is drained and
is empty, heater should remain off
heater should not work more than 20 hours per day
Mixer should be running while the material is being heated
A timer needs to measure the amount of time heater is being on in a day
If the heater works more than 20 hours per day, stop the heater and set a 20h-flag on (use the
accumulated value of the timer in the previous step to compare)
The heater timer needs to be reset manually
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Process Control Drain Section
When the tank is full and temperature is reached the set point, a drain Flag should turn on (use a latch
instruction)
Use a switch for the empty sensor – this switch should unlatch the drain flag and reset the level counters
so that the cycle restarts automatically