frequency setpoint for a micromster

bidza

may you please explain the attached program for me and how I can change the frequency setpoint using a plc

 Hello,

And the network above?

from the screenshot should be the "read" setpoint from drive

It's a FC 14 from Siemens modified?

The REC.N_Ist (REC=Receive(maybe)) is IN or TEMP like parameter?

bidza

may you please explain the attached program for me and how I can change the frequency setpoint using a plc

Hello,

The attached logic explain the data read from MM440 like drive running or stopped, drive status if fault or alarm etc. Via PZD2 drive running speed parameter is transferred to PLC drive speed is used to display.

MM440 set point is fixed & programmed in PLC logic in air compressor. It depends upon compressor rated pressure & air volume capacity. Why you want to change/modify set point? 

bidza

thanks guys I need to understand the highlighted part of the statement list it seems like a calculation related to those numbers im not very familiar with statement list. see the new attachment

 Hello bidza,

What you sent will not do, it is reading "from" Micromaster, or you send the entire FC14 or send a photo of the network above (maybe).

But pay attention to move parameter!!!!

bidza

I want to slow down the speed to suit the process requirements.

Please check the settable parameters list in manual & see if you could modify/adjust output pressure/air volume parameters.

Here is the description, I hope it helps:

1:  L #REC.N_Ist                           // Load 16 bit input word into ACC-1 L, consider the value to be                                                              // +100. This value come from the drive in Status word 2.

2:  ITD                                             // Convert ACC-1 L to 32 bit & Store in ACC-1.

3: DTR                                            // Convert ACC-1 32 bit to floating point & Store in ACC-1, the                                                                  // value will be +100.0

4: L 1.200000e+002                    // Load floating point +1200.0 to ACC-2.

5: *R                                               // Multiply ACC-1 to ACC-2 , the result will be +120000.0 & Stored                                                           // in ACC-1.

6. L 1.638400e+004                   // Load +16384.0 in ACC-2.

7. /R                                               // Divide ACC-1 with ACC-2. The result will be  +7.324218 & stored                                                        // in ACC-1.

8. L 1.000000e+002                  // Load floating point +100.0 to ACC-2.

9. *R                                             // Multiply ACC-1 with ACC-2. The result will be +732.4218 & stored                                                         // in ACC-1

10. TRUNC                                 // Truncate(Remove Decimal part) ACC-1 & store result in ACC-1.                                                           // The value will be +732.

11. ITD                                         // Convert the ACC-1 L register to 32 bit value.

                                                      // Here, In my opinion the instruction could be skipped as TRUNC                                                           // produces a 32 bit integer & the user is interpreting only the lower                                                         // register. The instruction will work fine, however, as the maximum                                                         // value of the operation will always be in the range of lower word of                                                       // accumulator.

                                                      // The result will be 32 bit value +732.

12. DTR                                       // Convert +732(DInt) to +732.0(Real)

13. L 1.000000e+002               // Load floating point +100.0 to ACC-2.

14. /R                                           // Divide ACC-1 with ACC-2. The result will be  +7.32 & stored                                                                 // in ACC-1.

15. T #Drive_Speed_Is            // Output the calculated value to Tag.

The drive will transfer a value between 0 & 16384 which corresponds to 0 & 1200 in this case.

The formula will then be like this Drive Speed = ((Register Value/ 16384)*1200) this will be the actual speed in whatever units you have selected at the drive ( rpm, lpm etc.)

The operations for multiplying & dividing with 100.0 are only for reducing the number of decimal places.

This certainly will be the data that is being read from the drive. To reduce the speed you have to check the data that is being written to drive.

KaushalKumarJoshi        

This certainly will be the data that is being read from the drive. To reduce the speed you have to check the data that is being written to drive.

 HelloKaushalKumarJoshi,

nice explanation, but our friend wants to change the input, this network is for returning from the drive what you said... so we expect, if he to us the right network