chonghyen

Hi Chakorules, Thanks for your information. I really appreciate it. I did got the communication between PLC and ID7 couples of day ago. Its a little bit different than what you have described. Here is what I do for siemens step7: Configure CP341 in hardware configuration. Set all relevant parameters. Copy all siemens CP341 standard funtion block. Change adderess of LADDR entries to 256 (based on adderess for CP341 in hardware configuration). Do not load 114 (INT) to _LEN parameter in SEND RS FC(this is the command in ASCII I will ask the scale what to do. Try to load 0 (INT) to it at initial. Set the scale to " Toledo Continueos" with CHECK SUM on. Now I am able to read the scale values continueously. This can be indicated by the RECV light on CP341 flashes contineously. I read the ASCII code in adderess of _DBB and _LEN paratemeter in "RECV RS" FC which I set earlier. Read _DBB and _LEN as CHARACTER so that I can straight away read as ASCII string. Lets say in _DBB I got read "OP" and _LED I got read "QR", the correct reading will be OP.QR kg. The unit will follow the same as it set in the ID7. Now here is the tough part. Siemens Step 7 do not have standard FB to convert ASCII to real or integer. But it do have ASCII to HEX. I converted it to a WORD which will give you reading of W#16#OPQR. Based on this reading, I can now use comparator to compare setpoint based on my process logic. As for tare the reading, I really have no idea on how to tare it. I tried to send ASCII command as per manual, it still doesnt respond. I use try and error method and get it done (But I do not know why and how it works). Load a value of 4 (INT) to _LEN parameter in SEND RS FC for couples of second and then set it back to 0. This will tare the reading in the indicator to 0.0 and will also read a value of 0 in the PLC after it. So this is all I needed so get the job done. As for others sophisticated command, I just forget it and touch nothing bout them. If anyone are interested in detail how I get this done, send me an email to get the sample program. Thanks and Cheers chonghyen@yahoo.co.uk chonghyen

Hi Ladies and Gentlements, I use 315-1 CPU with CP341 to communicate with Mettler Toledo ID7sx Base via RS232. Unfortunately I cant find and useful tips in Mettler Toledo website neither User manual on how to comunicate with CP341. I would like to seek your professionality on this. I have done everything I could on Step 7 on CP341. The sending and recieving counters are running and I really have no idea on how to read and write data from the scale. If anyone of you have done this kinda communication, please email me program example and guiden. Your help will be highly appreciated. Thank you very much and have a nice day!!! chonghyen@yahoo.co.uk chonghyen