Vacuum Excavation Truck LOGO! Project

Hello everyone, I am new to the forum and PLC programming and HMI programming with LOGO! . I am hoping that all of you experts out there can help me with my LOGO! Project. I am looking for help creating this program and hoping to learn the basics of what I need to do and can take things further. I am an Auto-electrical engineer that designs and builds vacuum excavators and horizontal diagonal drilling machines who is trying to expand his skill set. There are normally many methods I use to control my systems and in this case I opted to try Siemens LOGO! in my prototype. I have omitted lots of information about my design because it is not relevant for this project but that’s not to say that in the future if this is successful I may adapt LOGO! into other parts of my designs. At this stage I have just completed the construction and wiring of the control box for this machine, the total completion date of manufacture for the machine is the 31^stOctober 2019 so my programs must be ready for some form of testing with the rest of my design by this date in an ideal world.

I am open to any suggestions on all aspects of LOGO!s potential role in this design. Once the base program is 100% effective evolution of the design is a inevitable.

I expect to do a separate Project for the HMI program even though I imagine it will be very basic from what you are used too, I will need all the help available so thank you in advance!

Description of the Project

The Prototype machine is driven by the trucks transmission via PTO ( Power Take Off ). The PTO powers 2 hydraulic piston pumps that supply pressure to the open loop hydraulic system and drive 2 hydraulic motors one of which drives the Blower and the other drives the High Pressure Comet Water Pump.

There are numerous safety features and other systems that are all interlocked with the machine and vehicle that for this project we will not need to worry about.

LOGO! will switch on when the operator engages the PTO On Switch in the cab of the vehicle.

Blower Speed(generate three levels of vacuum)

The trucks RPM is controlled via an RPM CONTROLLER, the RPM controller has3set limits ,one of which is RPM IDLE, this Input must be used as a trigger by LOGO! once it has switched on to send a pre-set varied voltage to the DanFoss coil for Blower start-up speed. See Pneumatic Butterfly Valves for the information on RPM IDLE Input. The other two RPM limits ,RPM LOW & RPM HIGH Inputs will be the triggers for LOGO! to send a pre-set varied voltage for each RPM Input to the DanFoss coil that determines the speed of the Blower. Only RPM IDLE Input is required for Blower Start-Up Speed. RPM IDLE and RPM LOW Inputs are required for Blower Low Speed and all3Inputs must be active for Blower High Speed output.

Pneumatic Butterfly Valves(select vacuum or neutral of blower & open or shut-off sludge tank)

BV1:Butterfly Valve 1

BV1must be OPEN on start up. This is Blower in Neutral.

When LOGO! receives an Input from the Vacuum On switch, BV1 must CLOSE. This is Blower in Vacuum.

When LOGO! receives an Input from the Blower Unload switch, BV1 must OPEN and CLOSE five times in 30 seconds. Blower must be in Neutral to allow this output.

BV2:Butterfly Valve 2

BV2must be CLOSED on start up. This is Blower In Neutral and Sludge Tank Shut-Off.

When LOGO! receives an input from the Vacuum On switch BV2 must OPEN. This is Blower in Vacuum.

When LOGO! receives an Input from the Blower Unload switch, BV2 must OPEN and CLOSE five times in 30 seconds. Blower must be in Neutral to allow this output.

High Pressure Comet Water Pump(Pumps 38 litres of water per minute @ up to 4000 PSI)

HPCWP:

The truck carries 2000 litres of water used for digging by means of hydro excavation. The water system is protected by two float switches in the switching side of the system.

When LOGO! receives an Input from the Water On switch, a pre-set varied voltage will be sent to the DanFoss coil operating the speed of the pump providing Water Pressure 1.

When LOGO! receives an Input from the High Water Pressure switch a pre-set varied voltage will be sent to the DanFoss coil. The Water On switch Input must be active to allow High Water Pressure output. 

Hydraulic Boom(Raise, Lower, Extend, Retract, Slew CCW and Slew CW)

The hydraulic system used in this machine requires a signal to be sent to the Boom Supply Valve to prioritise the oil flow to that part of the system. When logo receives an Input from any of the boom functions a pre-set varied voltage will again be sent to the Boom Supply Valve.

Emergency Stop(Safety Shut-Down)

The Vehicle and the machine have an interlocked 24Vdc Safety circuit which re-sets the truck RPM to RPM IDLE. The safety circuit also cuts off the Hydraulic electrical circuit which immobilises the main operations system. When an Emergency stop button is pushed LOGO! needs to re-set to Start-Up conditions. If the hydraulic cooling over temp Input is received by LOGO! at any time LOGO! must re-set back to Start-Up conditions.

Hardware available

30W 24VDC-24VDC Power Supply

LOGO!8 12/24RCE

AM2 AQ Analog Output Module 2 x Analog Outputs

DM8 12/24R Digital Input/Output Module DI x 4/DO x 4

DM8 12/24R 4 x 12/24VDC Inputs/ 4x 5A relays

KTP400 Basic HMI Touch Screen

Hi, 

I've tried to make a rough start on the first part of your question. 

This is far from perfect, but perhaps enough to get you started?

In the first part we have 3 inputs for the analog output selection, exact voltage values need to be set. 

In the 2nd part I've created some switching logic for the BV valve. 

This probably needs more interlocks and logic, just see this as a start for expansion  

If this is something you are looking for and you need more help just let us know. 
If you are looking for something completely different I probably misunderstood you completely... 

Hello Luna

Yes what you have done is a great starting point I appreciate your help. The timer for BV1 is excellent but we need to add BV2 because for the blower control needs 2 butterfly valves BV1 & BV2 that work in direct opposite so 1 is closed the other is open at all times ,these 2 valves must actuate at the same time and can we change the program so when the vacuum on switch is active the blower unload switch cannot be active. thanks heaps Luna

morgs

Hi Morgs, 

Try the attachment. 

Again, this is far from finished, all loose pieces of program to get an idea. 

I now made the BV1 and BV2 to work inverted of each other. 

Of course it's also possible to have a seperate timer for it. This way however ensures they are never active at the same time. 

Regards Luna

Hi Luna

Wow  its beginning to look like my physical design concept and I really appreciate the fact you are putting your personal time into helping me. I am waiting on the official blower CFM (total cubic feet per minute) data from running our trucks finished air system from a test bench and then the Isuzu Rpm controller limit ratio data to begin to decide the actual voltages but we can assume that high RPM would send 80% of 24Vdc if switched through a standard potentiometer card so 19.2 Vdc and low RPM 60% = 14.4 Vdc then idle 9.6v so I presume that if on a 10v scale that 8v ,6v and 4v should be a reasonable starting point to run the program just now. This is the standard testing protocol for these Danfoss coils until I can run scale tests safely.

Can you explain the 4 voltages in the AQ please ? it will click quickly when you do lol.

thanks again !

The AQ's are nothing more than analog outputs. 

In this case I used the Analog MUX to determine the analog value. 

For instance, Block B001 (Blower Speed). 

This block has 3 inputs connected: En (Enable), S1 and S2. 

EN should always be active if you want a value from the MUX. 

So EN active and S1 and 2 not active results in a value of 250 (range from 0-1000, 2,5V)

EN active and S1 (S2 not active) results in a value of 500 -> 5V

EN active and S1+S2 results in a value of 750 -> 7,5V

I just made up some values, you need to determine the required values and adjust them in the blocks for the various analog outputs. 

There are more options to select the value, I now kept them all the same. 

This makes it easier to understand the various parts of the program. 

For the Boom value (which is only active or not) I could have used other options, but this gives some preparations in case you want to add conditions to the software. 

Again: I assume the software will need some further "tuning" 

ok Luna with you now. thanks .

Yes I have a lot of possible adaptations to include its very exciting. At the moment I am developing a Scanreco radio remote control system for this vehicle. Using this fully programmable radio remote opens up even more possibilities if applied with logos logic.

In-fact the remote control receiver would be capable of running this system without my control box and hardwired safety system, but would limit HMI to only radio transmitter which isn't practical in the machines working environment and wouldn't comply with the industry standards.

Anyway one step at a time ,well maybe two . It is a pleasure to have your assistance and I really look forward to the end result of this project. I have plenty of interesting ideas for logo projects once that is the case.

I find it incredible that it is possible to get this kind of help from complete strangers.

enjoy your weekend 

Morgs