Step7

This is kinda an automation task but it's a personal pet project for home. I've got an analog to digital converter hooked up to my PC and I'm writing a program in visual basic that displays a gauge in both analogue and digital formats for an analogue input value. Here's the problem/challenge: The analogue/digital converter gives me a numerical value from 0 to 255, my desired range on the digital readout will be -20 to +20, so analog input at 0 gives -20 and analogue input at 255 gives +20, any ideas on the maths involved to do this as it's been a long time since i was at college and cant remember how the heck to do something like this. PS. Not a student homework question, this is a complete home project. Thanks

How about using a non-contact linear transducer as opposed to an encoder like a Temposonic transducer, here's a link http://www.davidson.com.au/products/displa.../pdf/550739.pdf Look at the hydraulic series specs (dont have to be used for hydraulic applications) They do a 0-10V version or a 0-20mA version so you could hook up to an analogue input, we've reliably used these transducers on some of our larger machines for several years with no problems (except if someone treads on one) the transducer is a non-contact type and works on a magnetic principle whereby the position of a magnet is detected along the length of the shaft and they can have a resolution of upto 0.002mm which would be more than adequate.

I just checked with rswww.com and farnell's and they are discontinued from both suppliers, the only other option i can think of would be to contact your local siemens distributor and see if they can offer some support. You should be able to get the software relatively cheap now and the cable had in RS been knocked down to £40 from somewhere closer to £90, but if memory serves me correct when u get the software the cable comes free anyway.

If it shuts down with only a load attached it sounds like a faulty component going down under temperature rather than a fan speed problem as that'd knock it out instantly rather than only when a load is applied.

Unfortunately that price was correct £300 for the SW and about £100 for the cable from RS Components, Farnell's price was about the same. Unfortunately that's the firms choci of supplier so we have to go along with it even though there service seems to get poorer by the day (4 week wait for an S7-224) It didnt state in either catalogue wether the cable was included or not so i ordered one anyway, so hopefully I'll get 2 (one for personal use) As far as I'm aware the only Mitubisih plc's we use are FX series as for all our other equipment we stipulated that we wanted S7/S5 and we have had loads of gear come in from one of our other sites that has been closed down where they primarily used mitubishi hence all this new stuff to us.

Over recent weeks our plant hsa seen a lot of equipment coming in with mitsubishi FX0N, FX2N PLC's (all our other stuff is Siemens S7) so I decided to go and order some software and a cable. Just wanted to confim what i was ordering was correct as you guys will clearly know more about Mitsubishi PLC's/software tha i do Anyways, I've ordered GX Developer FX, am i right in thinking that suits all PLC's in the FX range i.e. FX0N, FX2N etc? And I ordered the 9 Pin serial to DIN cable SC09 which I assume is the correct cable. I hope i've ordered the right stuff otherwise my boss will go nuts as i've just spent about £600

or at least try several common password combo's first, if there's a TD200 scroll through all the messages first and see if someone's dropped the password there, if im passwording anything with a TD200 on it i always add a spare screen with a password reminder. Other than that try some common ones first like '0000' etc to see if you hit it lucky otherwise its a case of clear the memory and start over

Sounds like it's cooked, i've seen a few of these go south (main reasons are electrical guys replacing fuses/dc trip put back in repeatedly while a fault exists) They are repairiable but for the price of repair against the price of a replacement your better of taking the replacement route

I still cant see it, yes i can embed VBytes in the TD200 wizrd but i just cant see the required ladder or data block to turn it into something meaningful.

Hi there I'm moderately familiar with S7 but have hit a huge stumbling block in a little project i'm doing at work and it's driving me nuts (i'm sure everyone has been there once or twice ) Here's the prob. I'm building an automated lubrication system to cover several machines, i decided to use a S7-224 with a output expansion module and a TD200. Now i thought it'd be a great idea to have the option to display the status of the I/O on the TD200 for faultfinding purposes. I was planning on just displaying groups of 8 inputs on one message which would require two Vwords to be setup in the TD200 wizard but from that point i'm lost. One idea would be to write 16 Vwords into the data block that are the binary equivalent to the all the possible states of a group of 4 inputs, then just using MOV_W to move the correct VW to the TD200 embedded data address depending on the input states. Can anyone think of an easier way to do this as my program is already getting large and I could do with a shorter way of doing it. Many thanks Tom