Skip to Content

Register Login

Industry Online Support

Technical Forum

Navigation

S5 to S7 - a few questions

Created by: Asw19flier at: 3/4/2013 11:36 PM (2 Replies)

Rating (0)

Thanks 4

3 Entries

3/4/2013 11:36 PM	Rate (0)
Asw19flier Advanced Member Joined: 1/16/2013 Last visit: 5/15/2023 Posts: 36 Rating: (0)	Hi Gang, Im doing a step 5 to step 7 upgrade and have some questions regarding the some of the programming: - First one, after the translation I have the following: ….. L PIB 8; T IB 8; ….. Why would you want to have an image of the Peripheral input byte in input byte? Is this an old way of applying process image? - Second question I have relates to shift registers. After the translation: L QW 82 SLW 1 T QW 82 A Q 80.7 = Q 83.0 L QW 80 SLW 1 ...... I’m assuming that QW is really DBW of the opened in the beginning DB, correct? Also there is an image of the of the shift register on the applied to MW. I guess this is done because lack of DB space. Third question is: L 170 T #conv_akku1 TAK T #conv_akku2 L STW T #conv_stw L #conv_akku1 SLW 1 T #conv_number_of_dbb L 10 T #conv_create_db L #conv_stw T STW L #conv_akku2 L #conv_akku1 CALL "CREAT_DB" LOW_LIMIT:=#conv_create_db UP_LIMIT :=#conv_create_db COUNT :=#conv_number_of_dbb RET_VAL :=#conv_ret_val DB_NUMBER:=#conv_return_db Do I really need all that byte wise addressing of data? What is the exact purpose?I suppose I can just call SFC 22 with starting addess, block number and limits. There seem to be a lot of BR register in my conversion. Does anyone know a good write up on this? Thank you for all the input!

Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users AutoGen_312515

3/5/2013 8:28 AM	Rate (0)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 6/9/2023 Posts: 2969 Rating: (1025)	Hello Asw19flier Asw19flier First one, after the translation I have the following: ….. L PIB 8; T IB 8; ….. Why would you want to have an image of the Peripheral input byte in input byte? Is this an old way of applying process image? The Process image is updated at the start of the scan (in S5 as well as in S7). All this does is tomanually refresh (or update) IW8in the Process Image with the actual values from the input card to have the absolute latest values available (for any numberof possible reason which I can't say without knowing the whole S5 program and application requirements) Asw19flier Second question I have relates to shift registers. After the translation: L QW 82 SLW 1 T QW 82 A Q 80.7 = Q 83.0 L QW 80 SLW 1 ...... I’m assuming that QW is really DBW of the opened in the beginning DB, correct? Also there is an image of the of the shift register on the applied to MW. I guess this is done because lack of DB space. QW82 is well and trulyOutput Word 82 in the Process Image of the Outputs which canbe read accessed (it is NOTa DBWof the currently open DB). Why they also use an MWto store values is something I can't say (this part of the logic is not shown in your example). Note though that MW access is easier and faster in S5 as you don't have to explicitly open the correct DB firstso usage of MW's is/was commonly done. Asw19flier Third question is: L 170 T #conv_akku1 TAK T #conv_akku2 L STW T #conv_stw L #conv_akku1 SLW 1 T #conv_number_of_dbb L 10 T #conv_create_db L #conv_stw T STW L #conv_akku2 L #conv_akku1 CALL "CREAT_DB" LOW_LIMIT:=#conv_create_db UP_LIMIT :=#conv_create_db COUNT :=#conv_number_of_dbb RET_VAL :=#conv_ret_val DB_NUMBER:=#conv_return_db Do I really need all that byte wise addressing of data? What is the exact purpose?I suppose I can just call SFC 22 with starting addess, block number and limits. There seem to be a lot of BR register in my conversion. Does anyone know a good write up on this? Thank you for all the input! What "byte wise addressing of data" are you referring too? Anyhow, I agree that you clean up this section and simply call SFC22 with the correct values to create the DB (the S5 to S7 converter errs on the safe side with this kind of stuff to ensure the contents of accu 1 and 2 and the status word are preserved. This does lead to a rather convoluted converted S7 logic though). As for a good write up on this this, well,the S5 to S7 converter manual is not a bad place to startand there are plenty of FAQ's and forum post available too which you can find with a search here. I hope this helps
	Cheers fritz The advice and opinion given in this thread is that of the author and does not necessarily reflect the views of I S Systems Pty Limited. To find out how I S Systems can help you with your automation needs please visit www.issystems.com.au.
Suggestion To thank Quote Answer
This contribution was helpful to 3 thankful Users dchartier playerslight Marcjan

3/5/2013 5:58 PM	Rate (0)
Asw19flier Advanced Member Joined: 1/16/2013 Last visit: 5/15/2023 Posts: 36 Rating: (0)	Asw19flier Second question I have relates to shift registers. After the translation: L QW 82 SLW 1 T QW 82 A Q 80.7 = Q 83.0 L QW 80 SLW 1 ...... I’m assuming that QW is really DBW of the opened in the beginning DB, correct? Also there is an image of the of the shift register on the applied to MW. I guess this is done because lack of DB space. QW82 is well and trulyOutput Word 82 in the Process Image of the Outputs which canbe read accessed (it is NOTa DBWof the currently open DB). Why they also use an MWto store values is something I can't say (this part of the logic is not shown in your example). Note though that MW access is easier and faster in S5 as you don't have to explicitly open the correct DB firstso usage of MW's is/was commonly done. -Operating on MBs I do understand, however with the newer PLC it is cleaner and more funcional to use the DBs. According to my colegaue theyused Q's for the shift register because lack of memory space. Asw19flier Third question is: L 170 T #conv_akku1 TAK T #conv_akku2 L STW T #conv_stw L #conv_akku1 SLW 1 T #conv_number_of_dbb L 10 T #conv_create_db L #conv_stw T STW L #conv_akku2 L #conv_akku1 CALL "CREAT_DB" LOW_LIMIT:=#conv_create_db UP_LIMIT :=#conv_create_db COUNT :=#conv_number_of_dbb RET_VAL :=#conv_ret_val DB_NUMBER:=#conv_return_db Do I really need all that byte wise addressing of data? What is the exact purpose?I suppose I can just call SFC 22 with starting addess, block number and limits. There seem to be a lot of BR register in my conversion. Does anyone know a good write up on this? Thank you for all the input! What "byte wise addressing of data" are you referring too? Anyhow, I agree that you clean up this section and simply call SFC22 with the correct values to create the DB (the S5 to S7 converter errs on the safe side with this kind of stuff to ensure the contents of accu 1 and 2 and the status word are preserved. This does lead to a rather convoluted converted S7 logic though). As for a good write up on this this, well,the S5 to S7 converter manual is not a bad place to startand there are plenty of FAQ's and forum post available too which you can find with a search here. I hope this helps - Im referring to constant buffering of STW in order to contantly preserve the state in local data.

Suggestion To thank Quote Answer

|

Share this page:

Share this page on...

Follow us on