mart

Hiya chaps, I'm more of a fire fighting kind of PLC user and new to the programming sideso all help is very much appreciated. I need to create a small piece of code to monitor real times, for example if a door is opened for a given time I need to log what time is was opened until is was closed. This could happen a number of times over a 12hr period and would want to log each occurance and its total time for the 12hrs. At the end of each 12hrs the counter would be reset. Can this information be stored into a data block etc ? I need to write it in Step 7 and at a bit of a loose end because of the clocks, when I put a timer in for when the door opens do I need to link it up a clock in the CPU's hardware diagnostics. I've not got a PLC set up yet as its all development but plan to use a S300 for it. If I'm completely barking up the wrong tree let me know but all help would be welcome. Cheers Mart

Thanks Jesper, Your right by the way in what your saying about DeviceNet being 5 cores by way of 24v,0v, drain along with Can-H and Can-L as the comms. One other problem I've just stumbled upon is the different procedures in searching for an address, at present I'm looking at code written as STL in S7 and to go to an address I open up an FC, right click to "go to / loaction", then type in the address I'm after. But in function block code how do I search for an I/O address if I don't know where is it and is it different when using PCS7. Can you give me any pointers on quick searching for addresess

Jeff I know how you feel. I to am confident in RS logix and DeviceNet communications but going through the same trouble converting to Siemens which my new employer are installing. I recently attended Siemens training courses in Step 7 and PCS7 and find S7 does not have the same structure and lacks alot of the functions you may have taken for granted in A.B. One of my biggest gripes is as we are used to programming in ladder, programers now have the option to use Ladder, Function Blocks or Statement list and Statement list is find is a problem, each type of code written can not always be translated into another otherwise we could happily convert it to ladder. I've not really come in contact with Profibus which my new comms network and could do with any help from anywhere on that. With it being 2 core cable unlike DeviceNet in 5 core, is the comms signals sent through with the 24v and GRND cables to the ASI modules and how is the structured. All help on S7 PCS7 and Profibus will be greatly appreicated to get us of the starting blocks Cheers Mart

Due to a career change, I'm switching from RS logix 500 to Siemens S7 and I have not even seen the layout of the software. Can anyone provide me with information or software links were I can get free downloads or advice on converting over to Siemens. Thanks Mart

Thanks Chris, At present I don't know which particular Siemens program I will be using but I'll get in touch a distributor and have a good look through the disc. Thanks for your help Mart

Hi, Currently I'm using Allen Bradley RSlogix 500 for fault finding and trouble shooting but not as a PLC programmer, Due to a job change I'm required to have a knowledge of Siemens PLC's. I believe Siemens do not display like ladder logic so it maybe something I've not come across. I would appreciate it if anyone could give me their ideas in the difference of the two programs along with any links to simulation programs for siemens PLC's. All help would gratefully recieved. regards Mart

I'm using DeviceNet for the comms system on an installation and are trying to eradicate possible noise interferrence, the D/Net system consists of the Allen Bradley trunk and drop cables recommended which are internally screened. These are jointed into DeviceNet port box (part No 1485-P8T5-T5) before drop cables go to each individual node. These D/Net boxes don't have any ways or means to continue the EMC throught the cable screening except for the connection terminal for the drain wire. As for the EMC protection through the cable screen provisions do not exsist and each cable screen is floating between each box or node. I have been in touch with Rockwell Automation on this but received no joy, we are thinking of upgrading the system next time the Armor block system made by Allen Bradley but it appears the EMC may have missed out on that also. Has anyone had to modify their installation to include EMC protection and how did they get round it, or could anyone recommend any other brand of comms equipment other than Allen Bradley which is EMC compatible. cheers mart