S7 -1200 Modbus comunication with V20 and High Speed Counter

I've tried USS and Modbus comunication with two V20 drives following the examples from entry 63696870 and everything worked just fine until I tried to add a High Speed Counter in fequency mode in PLC  Input 0.0.

PLC is a 1215C DC/DC/DC CPU and has a 1241 module for the communication bus.

The comunication with the drives works fine but the PLC is not seeing the impulse train signal from the encoder in input I0.0. Looks like the PLC can't manage both task at the same time.

I tried to configure a HSC in a new program strarting from scratch, without the comunication modules, and the counter work perfectly, reading around 8500 pulses per second through input I0.0. 

My program has two V20 drives and needs more than one Speed counter. I'm starting to think this is not a reliable path to solve the application.

USS and Modbus examples have the same Issue.

Do you think there's a workarround for this or  should I drop it and move to analog signals speed control and digital start/stop command to control the drives?

We figured out. The problem was we didn't notice that the HSC inputs were filtered in the USS and modbus examples. 

I saw that this issue is a common problem for newbies as me.  I guess that this could be solved if Siemens adds a line in the HSC configurator to ask for user confirmation for the input filter configuration.

Hi flop,

Now i'm in this problem when communicate S7-1200 with V20 via Modbus and read HSC in the same time, my HSC pulse went wrong. So is it ok to do both in the same time. 

We were able to do both, comunications and HSC, by removing the filters in the input configuration for the digital inputs used inhigh speed counting.
The USS and Modbus examples that can be downloaded from siemens support  have filters in the digital inputs. So if you pick one of these examples and wanto to use a HSC you have to reconfigure the inputs by removing the filters. 

After doing this everthing went ok in our application.

New question published by krisson211 is split to a separate thread with the subject HSC pulse is wrong, it increases continuously while motor is not running.

Best regards
Jen_Moderator

New question published by adeebmostapha is split to a separate thread with the subject V20 should run in direction for 5 min.

Best regards
Jen_Moderator