straightjacketindustries

Hi, Thank you for the help so far, it has put me onto a few things, I am a diesel fitter by trade but after 10 years of breakdown repairs I have a very sound appreciation for quality wiring work! most of our breakdowns now failure wise are hydraulic or electrical / electronic in nature so I have had a thorough crash course in things beyond my understanding. I also don't even carry auto crimp terminals unless its a Deutsch style crimp, they just cause more problems than they solve. Definitely no twisting wires! Any way after much research (Google) I have found these http://www.robotshop.com/content/PDF/datasheet-de-swadj3.pdf Which should solve the problem of supply? there are switching buck regulators on eBay for $2 but I don't think I would trust those on a $500 PLC. I would still like some sort of fusing in the supply to ensure the PLC is protected. I would think current draw on any of the sensors I would be using will be minimal, a 5amp fuse usually supplies power to the entire controller on our equipment, running 20 odd sensors. After some experimentation I have found that the 8v sensors also put out a voltage as well as a duty cycle reading, ie 1v to 7.2v through its range, I will check to see if the current draw is acceptable on them this week. I am also sure that the speed sensors are a straight 24v supply on the 3 wire types and the 2 wire create the signal though the magnetic field "doover" on the end as it reads the chopper wheel. also will check and report back. Joe can you elaborate more on this? "A comment on Simon's last post - an NPN sensor is also known as an "open collector" sensor. Google this to gain some understanding. If you tie the output of the sensor to +24V with a 2.2K pullup resistor you can generate the signal you need for the PLC by connecting the junction of the sensor output and the resistor to the PLC input. The signal will be inverted. If you use a DI16 module you can wire it to accept NPN inputs, in which case the pullup resistor is supplied for you." I think I have come across this on proximity switches where they are three wire sensors and the pull up resistor must be internal? I haven't got my head around this yet. My googling has turned up yet more terminology that is conflicting... pull up/ load? ...(earth and ground stuff). I will need to sit down and study more. Have you got a schematic of this showing how it works? Next project.... I have decided to build a data logger monitor as well for testing hydraulic systems, this setup will utilisestandard 24v 4-20mA transducers 6-8 in total depending on what interface, I am considering a v570 for this as I would like to be able to see more at once and perhaps have real time graphs to help pick up where the erratic hyd function is. there is also an option for a flow meter in the future too. I have a smallish 24v battery available to use as the power supply and a regulator to charge DC-DC to ensure consistent power supply. My idea is to have the battery supply and transducers in one box/enclosure with test hoses running back to it, this can stay on the machine deck some where secure, and have a cable set to a second box for the PLC so it can be read from the cab somewhere out of the heat noise and dust. As long as I use quality cable can you see any issues with this Idea? Cheers Ben.

G'day Joe, I am hearing what you are saying about the use of 24volt sensors, I have considered the use of a industrial style sensor but in my experience they just are either not reliable or not cost effective in the application I would like to use them in, the cost to buy one industrial style sensor that is going to be able to live in the engine bay of a truck is a huge chunk of my budget. We have heavy equipment at work with industrial plc controls and the applicable 24v basic switch/sensor input and they fail far more regularly due to heat vibration and green death than any of the other OEM style sensors I would prefer to use. It also appears that Industrial sensors that would suit I would be paying a premium for, on a range of accuracy that I just do not need. The main sensors I would be looking to use are OEM CAT or Cummins supplied. Info is fairly short in supply and I have a small number of parts that I have enough info on to be able to use in regards to duty cycle and mV outputs through their range. From what I can tell it looks as though I will need to build some circuitry of some description no matter what I do, its whether or not I can do an interface that converts it all to a signal a PLC can use or do the whole lot from scratch like an Arduino based thing which in my short amount of research may be even further out of my range of understanding. Ben

Thank you for your reply. I have been looking into the sensors more and have found the following. Speed sensors, are as you say, both powered and passive, I can use either depending on what is easiest to use. I can easily find a powered 3 wire running approx. 0-1000 Hz at high idle at the signal wire. 0v common on PLC lingo would be the earth in a 12-24v sys I am assuming, just different terminology? I can get analog sensors that are 5v supply, a mistake I had made in my first post, .5v @-40*C to 4.46v @120*C for standard temps with similar values for the analog pressure sensors. I also have digital sensors that a 8v supply, the signal is in duty cycle, PWM 10-90% and can be used for pressure and temp. A bonus is there is a exhaust temp sensor that will read to 850*C in the same style. It would be good to keep them all at the 8v supply digital style for ease of design, but are these "digital" sensors a digital input referred to as an input on a V130 plc? does the PLC read the duty cycle on/off time as a NPN input or is it something else? I must admit that the difference in terminology between manufacturers and even industries is rather frustrating! If all my inputs are a frequency input am I better off going with another model of PLC as I cant see one with very many frequency inputs? Thanks again, cheers Ben.

Hi, I am an absolute newbie to PLC design, I have worked on systems using plc on a troubleshooting fault repairs level, but nothing more than wiring faults etc so I am sounding out the feasibility of me even being able to set this up by myself, and if what I am trying to do is possible with this range of products. . I am wanting to set up a Data logging and monitoring system for a project engine, At this stage I will be only using it for monitoring purposes, I may in the future use it to control some simple out puts, fault indicator light or a shutdown circuit, rather like a very basic engine ECM. My reasons for going down this route is as my target engine is antique by today’s standards there is no direct option for an aftermarket system which does not involve many $1000's (which are mostly targeted to petrol engine complete control, mine is diesel), and I want to be able to monitor up to 15 channels of information, which is a lot of gauges to look at simultaneously, which is my only other option. I am currently looking at using a vision 130 with an appropriate analog I/O module to use as the basis of my system. The following is the sensors I would like to monitor, 2 x timing sensors, 2 wire magnetic pick up, I am assuming these are classed as digital inputs? on/off as the sensor picks up the timing indicator. 7 x pressure sensors, anolog? three wire 8 volt supply style. 4 x temp sensors, thermocouples?, 2 x 0-120C*, 2 x 800C* Am I on the right track? Is this something I will be able to work through and program myself? I am use to OEM style 2 and 3 wire sensors are these compatible with this style of PLC or will I need a more industrial style of sensor? Thanks in advance, Ben

Hi, I am an absolute newbie to PLC design, I have worked on systems using plc on a troubleshooting fault repairs level, but nothing more than wiring faults etc so I am sounding out the feasibility of me even being able to set this up by myself, and if what I am trying to do is possible with this range of products. . I am wanting to set up a Data logging and monitoring system for a project engine, At this stage I will be only using it for monitoring purposes, I may in the future use it to control some simple out puts, fault indicator light or a shutdown circuit, rather like a very basic engine ECM. My reasons for going down this route is as my target engine is antique by today’s standards there is no direct option for an aftermarket system which does not involve many $1000's (which are mostly targeted to petrol engine complete control, mine is diesel), and I want to be able to monitor up to 15 channels of information, which is a lot of gauges to look at simultaneously, which is my only other option. I am currently looking at using a vision 130 with an appropriate analog I/O module to use as the basis of my system. The following is the sensors I would like to monitor, 2 x timing sensors, 2 wire magnetic pick up, I am assuming these are classed as digital inputs? on/off as the sensor picks up the timing indicator. 7 x pressure sensors, anolog? three wire 8 volt supply style. 4 x temp sensors, thermocouples?, 2 x 0-120C*, 2 x 800C* Am I on the right track? Is this something I will be able to work through and program myself? I am use to OEM style 2 and 3 wire sensors are these compatible with this style of PLC or will I need a more industrial style of sensor? Thanks in advance, Ben