Sinamics V20 MODBUS communication problem

Dear TechTeam,

Pls advise what could be a problem with my Sinamics V20. I can read Ok all modbus map from V20. 

I ran Cn011 macro to enable command and setpoint via modbus. then set P2014[0] USS / MODBUS telegram off time [ms] to 0, to avoid error of comm. timeout fault. 

I use modbus probe tool like Modbus Poll , which allows to wirte single words to any holding registers as well . 

Then I write 47Eh to STW , then freq. setpoint to HIW , then 47F to STW. And nothing - motor won't run. On BOP, I can see changing setpoint. But actual speed = 0, In current speed screen of BOP, Hz just blinking as  0.0 (actual) --> 28.3 Hz (setpoint.) 

so far no idea, thinking in this direction:

• there is some prohibit/safety function on DI, which is enabled via BICO etc.
• i did not connect motor, try just to run in v/f mode , the inverter still should give V/Hz PWM on UVW terminals. Maybe real motor is needed, because of current feedback etc,...

thanks, 

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Split from Comunication between S7-300 and V20 sinamics..

Good Morning.

What is going to be the master in the network?..

A while back I was networking an S7-1200 and several V20 drives on a Modbus network. The Siemens provided example was of great help -
https://support.industry.siemens.com/cs/ww/en/view/63696870

Even if you do not have the same configuration have a look at the example... or specifically look at the PDF document that goes with it. There is descriptions of of all elements of making the control work (include hardware, software, signalling, ...).

For your problem - have a look in the PDF document about the description of how the user activates the drive to run. Notice all the individual control bits that should be switched. CAREFUL - some needs to be TRUE while some needs to be FALSE.

You will find this information in a picture about the HMI usage - it is not spelled out that those bits should be ON/OFF. With this information you will know what control bits the MASTER in the network should trigger for the result you need.

I hope this helps you. Good luck.
w

Please check r0054 (via BOP) if it's really 47E and then 47F as you say.

Check r0052 if all the relevant signals are as they should be.

What are the values of those words when you're sending 47E and 47F?

HI, thanks for advice, still not solved the issue, but some new info

after power on, ZSW (status r0052 ) is 60224 , EB40h,  binary 1110 1011 0100 0000

after I write 47E, ZSW goes to EB31h 1110 1011 0011 0001

Initial r0054 = 0. Then I write 47E to STW and r0054 becomes 47E. After that, I write 47F (lowest bit = 1 to start the drive )  BUT r0054 still remains 47E, i.e. does not accept my change.

I supposed the thing was here - the bit #1 Ready to run in ZSW says the drive is not ready

But app. note for 1200 & V20 via modbus says:

You have set the control bits (STW1) according to Figure 4-2.         47E
xYou have entered a setpoint (HSW) >0 and <rated motor frequency.   yes
xThe status bits (ZSW) have been set as in Figure 4-2. I attached the figure from the manual and 
it truly is EB31h 1110 1011 0011 0001

It's the other way around. Bit 1 of r0052 is 0 because there is no ON/OFF1 (control word is 47E not 47F).

Please make sure P0840 = r2036.0 (ON/OFF1 command comes from USS/MODBUS not some other source).

Hello eam_rts,

Set P0840[0] = - & check.

thanks, colleagues

I checked 0840 , it was r2036.0. And I tried also to disable 0840 to 0 at all (As PISCEAN advised, if I got him right "Set P0840[0] = - & check.", "-" ?  what is it...)

Actually, I've just started to play with V20 and final application is as follows - command ON-OFF should come from DI terminals and freq. SetPoint to come from Modbus.

BICO for me complicated now, for I'm beginner, is it possible to disable bico at all , set  command src just from digital input and leave freq. src from Modbus? 

You can't really disable BICO - BICO is everywhere :)

You can just choose not to use it when it comes to DIs.

Anyway, you could check r2036.0 and check if its 1. If it's not then you're not sending 47F.

About mixed command and setpoint source. Check description of P0719 (= 5).

Provided relevant DI is set to 99 (f.e P0701 = 99) you can then set P0840 = 722.0 and achieve ON/OFF1 from DI1 for example.

Reset the drive into factory settings. Then everyone knows where you start from. You try some settings in manual to make motor turn first. After you try some example for Modbus RTU.

Bye.

New question published by Mike Troshin is split to a separate thread with the subject When start the drive with DI1 the motor rotates with an old frequency value and shows the old value on the BOP.

Best regards
Jen_Moderator