11/27/2014 5:36 AM | |
Posts: 6 Rating: (0) |
Hi there, Thanks for your reply. Now i shall explain my problem in detail. We have made a small simulator kit in order to demonstrate the working of a PLC. The PLC is Siemens Simatic S7 – 300. The CPU is 315 – 2DP. We have 2 I/O cards one Digital and one Analog. As far as digital side is concerned we do not have problems. The Analog side is the area of concern for us. The Analog module is SM334 module with 2 sets of inputs and outputs. The input addresses are PIW 272 and PIW 274. Obviously the input is wired for Voltage not Current. And the Outputs are PQW 272 and PQW 274 which is also wired for voltage. And the voltage range is 0-10 volts. We have 3 digital meters 1 for input and 2 for output. There are 2 potentiometers on the input side by which the input to the PLC is varied from 0 – 10 volts. The input to PIW 272 is connected through potentiometer 1 and PIW 274 is connected through potentiometer 2. But there is only one digital meter to display this input which is wired through a 3 position toggle switch. Now the program is L PIW 272 T PQW 272 So when we rotate the pot the input is displayed on the input meter and output is displayed on the output meter, which are the same. Now can we add ramp function in to this program? Our requirement is that if we turn the potentiometer really fast to full voltage ie 10 v , we need the output to gradually rise to 10 volts slowly. We need to add the same thing when we decrease the input. Now there is a sharp rise we need the output to slowly follow the input. I checked online what I got was the idea to make a user defined FC37 block. But I am yet to materialize that. Attachmentramp-example.zip (1246 Downloads) |
11/28/2014 9:36 AM | |
Joined: 8/27/2010 Last visit: 4/13/2024 Posts: 417 Rating: (37) |
Hi! Now its more clear for me, thanks. I can suggest you to look atthis guidefor ramp-function generator. This is for STEP7. For TIA, usethis link. Feel free to ask additional questions. |
12/4/2014 1:14 PM | |
Joined: 6/24/2013 Last visit: 9/20/2024 Posts: 1628 Rating: (421) |
Hi Easy way: 1. configure let's say MB0 as a Clock Memory [go to HW Config then CPU and set Clock Memory Byte to 0 and tick enabled] 2. the clock gives You 100ms wave (when You do FP and FN You can have 50ms pulses) 3. Ramp Function would add / subtract values as long as they are lower / higher than a target. Example Function attached in PDF printout. Inputs: - Target as PIW value (0..27648) - Ramp Time (time needed for ramp from 0 to 100% in s x 10 i.e. 10 = 1 second. t<=0-->No Ramp) - Enable (1 = enable ramp; 0 = ramp to 0) - ESTOP (1 = OK; 0 = ESTOP - force immediate Output = 0) Outputs: - Ramped Value Globals: M0.0 - 100ms Wave (from clock memory) AttachmentFB1_Ramp.pdf (1882 Downloads) |
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