Industry Online Support
Technical Forum
11/18/2013 8:01 AM  
Posts: 22 Rating: (0) 
Dear All, Project Type : PCS7 Hardware : FM350 6es73501ah030ae0 Settings : Operating Mode: Frequency Measurement SW Gate Updating Time : 10 * 10ms Encoders: 24V Pulse and Direction Max.Frequency Range : 200KHZ Sensor Input : Source CFC : CH_CNT FB127 Channel driver for FM Module/Counter Output Problem: For the Input as ID536 or IW536  88.0HZ to 88.4HZ Frequency Input, then the Flow Value will be 25267.6 88.5 to 88.9, 89HZ Frequency Input, then the Flow Value will be 25554.9 In this, I got the counter value output ( Pulses/Sec) ACT_CNTV as DINT in FB127 (100ms). So when the frequency value changes as 88.5, rounded and resulted as 89HZ equivalent flow value. Counter Output in FB127 is; 5100 5200 5300..... increasing  pulses/sec So I got fluctuating in calculating the flow value barrel/day. This 1HZ frequency change leads to big difference as 287 barrel/day.. Its fluctuating between 25267.6 & 25554.9 barrel/day. I need to calculate the Flow Value for every decimal point changes at the frequency. How do I convert concern count value into floating value to precise the flow value per decimal point. 88.0  25267.6 barrel/day 88.1  ?? 88.2  ?? . . . 88.9  ?? 89  25554.9 Cheers, Vikki

11/18/2013 4:29 PM  
Posts: 220 Rating: (11) 
Hi vikki, can you give us a third measurement Hz > barrel/day, couse with just 2 points I can't say if it's constat or exponential curve.

11/19/2013 7:05 AM  
Posts: 22 Rating: (0) 
Dear No Name, For Eg: From Field , Frequency is 88HZ It is read as hexa decimal value by CH_CNT FB127 Block and It delivers the outputin the form of count value as DINT. So I have taken the difference value of previous cycle and actual cycle, then this difference value will be equals to Input Frequency ( same value). Then further I am doing the calculation as follows: EG: Freq (pulse/sec) x 60 (min) x 60 (hr) x 24 (day) Flow rate (barrel/day) =  300.916 (KFactor) 88HZ > 25266.851 barrel/day Now I need to show Flow Rate for decimal change of real flow value at field ( mean frequency ). 
Last edited by: vikkipro at: 11/19/2013 7:06 AM 

12/2/2013 8:03 AM  
Posts: 22 Rating: (0) 
Dear All, I got the solution. From FM3501 FB127 block, there is another output called as ACT_MSRV, In that I am receiving actual value of frequency from field with three decimal point changes. Just we need to divide that double integer value by 1000 and then we will get the result. For this, we need to make settings in hwconfig as frequency measurement,swgate,10x10ms and FB127 calling OB in 100ms. Thanks for your support 
This contribution was helpful to1 thankful Users 
4/7/2015 4:23 AM  
Joined: 11/30/2007 Last visit: 11/5/2024 Posts: 12 Rating: (0) 
Hi Viki, Would you please share the project to me? I also doing quite same project as you are.
Regards, Baron

Follow us on