AS - Interface - does it work?

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Thread Starter

Mark

ASi looks ideal for small i/o applications. Simple to build, configure and install.Well at least on paper! Has anyone got an opinion on ASi? Is it easy to install and configure? Is the PLC/PC master easy to configure? I have some reservations about the 100m limit on individual bus cables, with repeaters and extra power supplies etc. required beyond 100m. Wondering if my buget will be eaten away by these items? I want to avoid hardwired everything (which is what my firm does at the moment - and its just crazy, running 20 instrumentation cables 200m to remote temperature probes when a simple bus system would do), but do not want something that takes an age to programme, configure and train engineers for weeks on end to install and test. Thanks Mark
 
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Meeuwis Bouw

> ASi looks ideal for small i/o applications. Simple to build, configure and install.Well at least on paper! ASi IS easy to build and learn. > Is the PLC/PC master easy to configure? I believe most vendors offer some form of automatic configuring. I used the master that goes into the Siemens S5 95U PLC. It configures automatically if you give all slaves an unique adress first. > but do not want something that takes an age to programme, configure and train engineers for weeks on end to install and test. All I/O enters in your PLC program the same as you are used to, only on different adresses. Training of engineers took us 1 day. Check out www.as-interface.com The site tells you all you need, including an estimate on cost. Meeuwis Bouw, Superfos Packaging.
 
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Audun Alvestad

The ASI system is a good system for digital IO, it's not for analog IO. You can use analog IO but this will require at least one slave for one signal. The PLC will handle the ASI IO just as any other IO of the PLC so this is easy. If you have long distances you should use profibus (or any other bus) gateways to the ASI Then you should be able to combine the best of the two bus systems. Im your case a profibus temp.module and ASI-gateways to DIO. I could explain how to use ASI in a few hours, and the amount of documentation will be reduced dramatically. Also the the time looking for errors in your system will be redused and don't forget the cost of laying cable around in the systems.
 
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Steve Snodgrass

I have implemented several ASi networks over the last few years using the Siemens S7-200 ASi master. Programming and configuration was clumsy at first but once you get into it, it's pretty easy. As far as installation, if you can install low voltage outdoor lighting, you can install an ASi network. As far as cost: The hardware required is not cheap but we have found that it is a trade-off between the increased cost of the hardware and the decreased cost of wiring the system. On small applications, the cost of ASi will exceed the old conventional method, On large applications or in your case: long distances I think ASi will be a very competitive option.
 
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Garrett Place

> ASi looks ideal for small i/o applications. Simple to build, configure and install.Well at least on paper! This is the perception of AS-i. Although it has a base 100M length and 31 Node capability, it is not limited in scope. An application that we worked on contained 7,000+ digital I/O points through the plant. It was networked with ProfiBus on the higher level with multiple AS-i/ProfiBus gateways on the lower level. The 7,000 I/O points were connected to AS-i. The savings were incredible. AS-i becomes almost transparent to most users. It can be directly connected to most major PLC platforms or used as a stand-alone system. The biggest savings can be seen in the installion and troubleshooting phases of the project. I would be glad to answer any questions you may have abpout this network or put you in contact with a company that has used AS-i in a similar industry. You can reach me at [email protected]
 
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D. C. Pittendrigh

Hi All This is another sizzler, I don't know if I like the way the question is phrased as it leads to ambiguity, however, my experiences of ASI are based on 4 wharfside loaders and a stacker reclaimer which have been installed with ASI in my town. Those of you who have been on the list long enough to recognise my affiliations, can probably guess who the manufacturer is. Unless I get hit by a bolt of lightening, I will NEVER touch this stuff again, it has caused me more heartache than all of the rest of the engineering problems I have had to deal with throughout last year. I have to admit that had i been responsible for the installation of the equipment in any of the above cases, I would probably have done things differently, but then had i been responsible I would probably have used better known technology. I can go into the reasons why the equipment failed but let it suffice to say that it in all cases it seems to be rather susceptible to damage from EMC. I dont know if this is a manufacturer specific problem, which is where the ambiguity comes in. I have seen some very good looking ASI stuff from Hirschmann and might be tempted to test it some time (bolt of ligtening permitting) and the technology certainly represents a good idea. Regards Donald Pittendrigh
 
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My response would be that given the following caveats, ASi works very well for us. 1) Avoid using in very high EMI areas- i.e. welders, etc. 2) Keep cable runs short as possible. i.e. Don't leave excess cable laying in trays, etc. if it can be avoided. Long cable runs parallel to servo wiring, etc. is asking for trouble. 3) Keep in mind that hardware costs WILL increase, but labor savings on installation and troubleshooting are higher than the material costs-- the bottom line- you save money. 4) DON'T use 8mm connectors; these make life painful. Stick with 12mm where possible. 5) I cannot address the issue of repeaters, as I have not had occasion to use them. 6) Our experiences have been limited to using a single ASi hardware vendor- P&F, and their support has been FANTASTIC. Our installation with ASi using Allen-Bradley SLC-5/04 and S+S Technologies ASi card went very fast, easy, and painless. You can write or phone me, and I can give you more particulars, if you desire. jfv John F. Vales Director of Technology [email protected] Wes-Tech Automation Systems, Inc. 720 Dartmouth Lane Buffalo Grove, IL 60089 847.541.5070 (main) 847.419.7950 (direct) 847.419.7988 (fax)
 
> suffice to say that it in all cases it seems to be rather susceptible to damage from EMC. I dont know if this is a manufacturer specific problem, > > Regards > Donald Pittendrigh > According to the glossy sales paperwork the suppliers are pushing out, ASi is supposed to be good for using around welding (robotic) arms and the like. I thought this was its selling point - its robust and therefore relatively simple to install because (apart from good working practice) less effort has to taken to avoid interference! Not that welding machines are anything to do with my application.
 
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Michael Griffin

At 09:10 23/02/01 -0500, Mark ammonia_hurts wrote: <clip> >Does anyone have any comments on their experience of ASi? >ASi looks ideal for small i/o applications. Simple to build, configure and >install.Well at least on paper! Actually, I was just thinking about writing a message on exactly this subject, as I want to look more seriously at using ASI. I don't have any experience with it, but I've done some research that may interest you. <clip> >I have some reservations about the 100m limit on individual bus cables, with >repeaters and extra power supplies etc. required beyond 100m. Wondering if >my buget will be eaten away by these items? I think ASI is not really intended for long cable runs. It is intended for small systems spread over a small area. A typical example would be a small assembly line using Bosch conveyor. There are gateways which let you connect ASI systems to Profibus (Profibus for the long haul, ASI for local distribution), but I don't think this is what you really had in mind. >I want to avoid hardwired everything (which is what my firm does at the >moment - and its just crazy, running 20 instrumentation cables 200m to >remote temperature probes when a simple bus system would do), but do not >want something that takes an age to programme, configure and train engineers >for weeks on end to install and test. <clip> ASI seems to be more intended for digital I/O such as valves and proximity sensors, rather than for analogue. There is an ASI analogue module from Siemens, but I have heard some negative things said about it. ASI is a very interesting idea, but I'm not really sure it is intended for your particular application. Since you seem to be talking about instrumentation, I am sure you have looked at the various "fieldbuses" which are intended for that. There are lots of different ones (too many), and a recommendation of which one of them is the "best" is another discussion altogether. ********************** Michael Griffin London, Ont. Canada [email protected] **********************
 
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Garrett Place

> I think ASI is not really intended for long cable runs. It is intended for small systems spread over a small area. A typical example would > be a small assembly line using Bosch conveyor. There are gateways which let you connect ASI systems to Profibus (Profibus for the long haul, ASI for local distribution), but I don't think this is what you really had in mind. This is a great example. There are, however, manufacturers of AS-i products that incorporate two masters into the same housing. This enables one program to operate over two AS-i networks for a total length of 200M without repeaters. > ASI seems to be more intended for digital I/O such as valves and proximity sensors, rather than for analogue. There is an ASI analogue module > from Siemens, but I have heard some negative things said about it. This version of AS-i (2.0) is not suited for multiple analog points. The new version (2.1) will allow multiple analog points on a single node with a faster response time. Looks like you've done your homework Michael. If you have any questions you can reach me at 610-524-2017. Garrett Place ifm efector, inc. [email protected]ector.com
 
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Michael Griffin

I have been looking at using ASI, and so this subject happens at a very convenient time for me. I would be interested in hearing more details on people's experiences. At 17:21 23/02/01 +0200, Donald Pittendrigh wrote: <clip> >however, my experiences of ASI are based >on 4 wharfside loaders and a stacker reclaimer which have been installed >with ASI in my town. These sound like fairly large machines, if they are the type I am thinking of. What sort of distance were the ASI networks spread over? Were the cable or devices outside? <clip> >I can go into the reasons why the equipment failed but let it >suffice to say that it in all cases it seems to be rather susceptible to >damage from EMC. I dont know if this is a manufacturer specific problem, >which is where the ambiguity comes in. I have seen some very good looking >ASI stuff from Hirschmann and might be tempted to test it some time (bolt of >ligtening permitting) and the technology certainly represents a good idea. <clip> Did the installation use the flat cable, or round cable? If round cable was used, was it shielded? "John F. Vales" also mentions problems with EMC in noisy enviroments. I could imagine that very long runs of the flat cable might be susceptable to picking up noise regardless of the manufacturer. Do you perhaps think the problem may have been more one of an unsuitable application, rather than any fundamental problem with the technology? John F. Vales wrote: <clip> >1) Avoid using in very high EMI areas- i.e. welders, etc. This seems to be the same problem as Mr. Pittendrigh had. What sort of welders are you talking about - arc (e.g. TIG) or resistance welders? How close are you talking about - millimeters or meters? Do you know if you were picking up the noise via sensors which were located very close to the source (this happens with conventional wiring), or was the cable acting as an antenna? >2) Keep cable runs short as possible. i.e. Don't leave excess >cable laying in trays, etc. if it can be avoided. Long cable runs >parallel to servo wiring, etc. is asking for trouble. I assume this is the flat cable you are referring to? Did you consider using shielded round cable for long runs in cable troughs? Would you recommend avoiding running ASI cable in wiring troughs with other cables? >3) Keep in mind that hardware costs WILL increase, but >labor savings on installation and troubleshooting are higher >than the material costs-- the bottom line- you save money. This is exactly the point which interests me. The applications I am looking at involve short runs of a couple of meters or so within small machines. These would typically involve a dozen solenoid valves and two or three dozen sensors (proxies, MRS switches, photo sensors, etc.). In addition, there would be separate conveyor systems with pallet control and manual load stations spread out over a distance of 10 or 15 meters. The labour saving would not be just with the field connections, but also with the internal panel wiring (PLC I/O to terminal blocks). I also expect the control panels to be smaller, which is an additional advantage in my applications. In the control panels in equipment that I deal with, typically half or more of the panel size and most of the assembly time is consumed with internal wiring terminations. Do you have any estimates for how much time you saved on panel assembly and field termination? >4) DON'T use 8mm connectors; these make life painful. Stick >with 12mm where possible. <clip> What connectors are you referring to? ASI with flat cable doesn't by itself use any connectors. Are you referring to the receptacles on the input modules where you would plug in proxy cables? What was the problem with the 8mm connectors, and why were the 12mm better? ********************** Michael Griffin London, Ont. Canada [email protected] **********************
 
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Andrew Piereder

I've set up a few ASI networks in conjunction with SST's ASI module for the AB SLC 50x. On one occasion the customer was not using an ASI-specific power supply-big no-no. The network is highly-engineered which means it's not tolerant of "alternative" cabling, connectors, power supplies, etc... When you do use conforming components, it works remarkably well and right out of the box too! Its a bit-oriented master-slave network with a maximum of 31 slaves and 100m cable length. The cable can be extended to 300m with repeaters. You normally program a slave device using a handheld (slaves come defaulted to '0'), but some scanners let you do it through their software as well. Slaves can be replaced while the network is running if the have matching IDs and I/O. The scanner configures their address to the existing address automatically. Parameterization is not stored in the slave and must come from the scanner. Its not difficult and the performance is excellent--highly reliable. The system gives a user tremendous flexibility in positioning, replacement and of course saves on wiring and related diagnostic challenges. I have seen the system implemented in pick-and-place equipment where the inherent flexibility of the bus is perfect for reconfiguring the machines with new tooling without substantial underlying changes in wiring and I/O configuration. Sorry, I have nothing bad to say about it... Andy Piereder Pinnacle IDC
 
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D. C. Pittendrigh

Hi All >> These sound like fairly large machines, if they are the type I am >>thinking of. What sort of distance were the ASI networks spread over? Were >>the cable or devices outside? Very large machines > 500tons (metric) and 40 - 50 metres high. Cable runs were outside and up to about 50M, one of the installation errors is that they were run on cable racks together with power cables, the manual says this is allowed, I say NO!!! One of the machines the cable run is short, inside the MCC panels and suffers from induced currents every time one of the (many) contactors opens or closes. >> Did the installation use the flat cable, or round cable? If round >>cable was used, was it shielded? "John F. Vales" also mentions problems with >>EMC in noisy enviroments. I could imagine that very long runs of the flat >>cable might be susceptable to picking up noise regardless of the manufacturer. Flat cable was used in the inside installation and screened twisted pair in the outside installations. >> Do you perhaps think the problem may have been more one of an >>unsuitable application, rather than any fundamental problem with the technology? I think the IDEA of this technology is correct, convenient, and financially attractive, I also think the installation standards advocated in most of the ASi texts are optimistic at best, and in some cases downright misleading. I think the equipment I was subjected to was under designed for industrial applications. >> >1) Avoid using in very high EMI areas- i.e. welders, etc. Yes absolutely!!!! >> >2) Keep cable runs short as possible. i.e. Don't leave excess >> >cable laying in trays, etc. if it can be avoided. Long cable runs >> >parallel to servo wiring, etc. is asking for trouble. This will help and is one of the places where experience tells me the ASi texts which I have read are all incorrect. >> I assume this is the flat cable you are referring to? Did you >>consider using shielded round cable for long runs in cable troughs? Would >>you recommend avoiding running ASI cable in wiring troughs with other cables? Screened cable and beware of earth loops like any other serial comms applications, don't trust the flat cable and don't trust the installation instructions. Regards Donald Pittendrigh
 
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D. C. Pittendrigh

Hi Andy and others >>Sorry, I have nothing bad to say about it... >>Andy Piereder >>Pinnacle IDC We will forgive you for having nothing bad to say, it looks as if that may be the exception, but in the interests of promoting what otherwise appears to be a good idea, could you let us know what peripheral devices you had hanging on the ASi bus, I think this is where the week point lies with the stuff I have been exposed to. Regards Donald Pittendrigh
 
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Michael Griffin

At 09:52 27/02/01 +0200, Donald Pittendrigh wrote: <clip> >Cable runs were outside and up to about 50M, one of the installation errors >is that they were run on cable racks together with power cables, the manual >says this is allowed, I say NO!!! It may be that because these particular machines were very large, the amount of power which was being run in the power cables was much greater than anyone involved in designing ASI had considered. Greater currents would generate a lot more EMI than the hardware was tested for. >One of the machines the cable run is short, inside the MCC panels and >suffers from induced currents every time one of the (many) contactors opens >or closes. <clip> This is particularly of interest, as the latest ASI stuff from Siemens is special hardware for use in MCC panels. It is "special" in that it is intended to allow easier mounting to contactors (to control the coils) - it may not be any better hardened. >Screened cable and beware of earth loops like any other serial comms >applications, don't trust the flat cable and don't trust the installation >instructions. <clip> If you can't use the flat cable, a lot of the ease of installation of ASI dissappears. The idea was you run the cable around your machine in some convenient pattern, and then just crunch on the boxes where you need them. I think I am dealing with a much more benign enviroment, but I will avoid using it for motor contactors. This has given me some pause for thought though. I was hoping that by using something simple, I would avoid problems. There are some ASI "pneumatic modules", which are combined pneumatic valves and sensor inputs packaged inside a rectangular ASI style box. These look ideal for conveyor systems. For example, the valve could actuate a pallet stop, and the inputs could monitor pallet presence. Has anyone used any of these devices, and would they like to comment on them? ********************** Michael Griffin London, Ont. Canada [email protected] **********************
 
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Garrett Place

> There are some ASI "pneumatic modules", which are combined pneumatic valves and sensor inputs packaged inside a rectangular ASI style box. These look ideal for conveyor systems. For example, the valve could actuate a pallet stop, and the inputs could monitor pallet presence. Has anyone used any of these devices, and would they like to comment on them? Michael, I would like to preface this response by letting you know that I am not a salesman. I work for a company that manufacturers AS-i equipment and was one of the original 11 members of the AS-i Consortium. My responsibility in this company is solely technical support and marketing for AS-i products. It is exciting to see so much interest in this technology. Now that I have that out of the way ... you ask if anyone has used the pneumatic modules for AS-i. My answer is YES. If you would like to speak to one of these companies directly please contact me at 610-524-2017 and I will put you in contact with their engineers. These companies are also using AS-i to fire motor starters in a remote box. To date, there have not been any issues with this application. AS-i is a very robust system. I have seen, however, mis-application of the system to a point that the system will not work. The "manuals" state that you can run the flat cable in the harshest EMI environments. I, however, would ALWAYS recommend a separation of high voltage lines and data lines. I would be interested in knowing how the AS-i cable was applied in DC's application. I would also like to state that DC's problem is not manufacturer specific. If he is having the problem with brand x he more than likely will have the same problem with ours or any of our competitors equipment. Good luck with your application Michael. Garrett
 
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D. C. Pittendrigh

Hi All >>Cable runs were outside and up to about 50M, one of the installation errors >>is that they were run on cable racks together with power cables, the manual >>says this is allowed, I say NO!!! > It may be that because these particular machines were very large, >the amount of power which was being run in the power cables was much greater >than anyone involved in designing ASI had considered. Greater currents would >generate a lot more EMI than the hardware was tested for. Just to put some perspective on this the nearby power cables were feeding 4 motors of around 30Kw each, the thing is that the motors were connected to a vector control variable speed drive (which was wrong from the beginning as they are in parallel, but that's a whole 'nother can of worms) >>One of the machines the cable run is short, inside the MCC panels and >>suffers from induced currents every time one of the (many) contactors opens >>or closes. ><clip> > This is particularly of interest, as the latest ASI stuff from >Siemens is special hardware for use in MCC panels. It is "special" in that >it is intended to allow easier mounting to contactors (to control the coils) >- it may not be any better hardened. The part number was 3RK 1402 3CE00 0AA2, if this part number is on your "safe for MCC use" list, best be very careful. >>Screened cable and beware of earth loops like any other serial comms >>applications, don't trust the flat cable and don't trust the installation >>instructions. ><clip> > If you can't use the flat cable, a lot of the ease of installation >of ASI dissappears. The idea was you run the cable around your machine in >some convenient pattern, and then just crunch on the boxes where you need them. > I think I am dealing with a much more benign enviroment, but I will >avoid using it for motor contactors. This has given me some pause for >thought though. I was hoping that by using something simple, I would avoid >problems. In all fairness I have seen the above equipment working in this way in a small plant that makes matches, where the customer is a happy man, the trick is definitely to stay away from electromagnetic noise. Regards Donald Pittendrigh
 
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Andrew Piereder

Unfortunately, I can't recall specifically. I seem to have a vague impression of Festo values, but I can't confirm that. Andy P.
 
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