slc 5/05 setpoints & logic

[ddevins 0]

Hello, I'm a bit rusty but have been doing this for many years. I'm using a 5/05 and RSView SE with both analog in and analog out cards. A 4-20ma signal out is controlling the VFD with max 100% (60hz) and min. 15%(10hz). Comm is ethernet. I need to enter VFD speed % on the HMI in whole percent and have it change the speed of the VFDusing analog out 4-20ma. I also have to enter setpoint of product to transfer and move number to current value window to display. A new value can be entered and it will move to current value display. There are also min and max displays that can be entered and will be displayed, but these must be changeable by password control. Anyone recently did this and would have some .rss or .pdf logic I could use and look at?? Thanks for reading this and thanks for any assistance in advance

[TimWilborne 108]

I would do an SCP instruction Minimum Input 0 Maximum Input 100 Minimum Output 3277 Maximum Output 16384 This will convert your 0-100% to 4-20mA. Then put a limit on your entry cell of 15-100%. You could put the entire scaling in the SCP but I think this way is easier to understand when you are looking at the program later on Edited 13 Apr 2006 by TWControls

[Guest]

Greetings ddevins, it looks like my distinguished colleague, TWControls, has beaten me in the "Posting Olympics" again ... but since I have a sample program prepared, I'll go ahead and post my version too ... notice that I've made some assumptions (gosh I hate that word) about your hardware and how you have it assembled ... if this isn't close enough, please post again with more detail ... and welcome to the forum ... PS Edit ... I think that 15% is closer to 9Hz ... not sure if it makes a difference to you - but I thought that I'd mention it ... SPEED2.pdf Edited 13 Apr 2006 by Ron Beaufort

[TimWilborne 108]

And once again you wonderfully detailed post has shown an error in my solution. I copied the 4-20 input scaling parameters off of a program of mine and ASSUMED that the output parameters were the same. Yes assuming makes an... 4-20mA Input 3277 to 16384 4-20mA Output 6242 to 31208 Edited 13 Apr 2006 by TWControls

[TimWilborne 108]

You may also want to look at THIS manual. Pages 4-6 through 4-8 gives you the the decimal to Voltage/Current conversions. I appears (I won't assume ) that the conversions are the same for all SLC analog modules

[ddevins 0]

ddevins here again. Thanks much for the time and help. Been a while since I've done this particular type of logic. This will certainly get me going and hopefully complete this soon.

[TimWilborne 108]

And thank you for coming back and letting us know if the info helped you or not