A510 VFD Modbus RTU via RS485_DI state values in register

[ikhan123]

Hi,

I have a Teco Westinghouse A510 VFD which i am controlling a 3phase motor/hoist and I am controlling using the Modbus Library via RS-485 and using serial com RTU.

I am getting the motor to spin and write to the registers, however, I am having difficulty reading a particular register with multiple bits that I need to access on the same register, see the images below (Modbus Com manual for VFD). I have uploaded my vi below and also the modbus manual for the VFD for reference. 

I need to access the DI state to read if they are open (0) or closed (1). Also, does the Modbus API control the CRC check or do I need to include that somehow, if so how?

Any help would be greatly appreciated.

Thanks,

[ZYOng · Accepted solution]

Read the register 2522H. It should return a U16. Then convert the U16 to Boolean array.

Modbus Library will handle the CRC.

[ikhan123]

Hi ZYOng,

much appreciated.

Thanks.

[ikhan123]

Hi,

I also want to write to a register with multiple bits as in the above example but instead of reading a list of booleans, how would I write-to or read non-boolean from a sub-register?

Please see the figure below, how would I write to register to 2501H bit F to turn the Torque command set by Communication: ON

Thanks for any help and support.

Regards,

[ikhan123]

Hi,

I also want to write to a register with multiple bits as in the above example but instead of reading a list of booleans, how would I write-to or read non-boolean from a sub-register?

Please see the figure below, how would I write to register to 2501H bit F to turn the Torque command set by Communication: ON

Thanks for any help and support.

Regards,

[ZYOng]

Bit F is the 15th bit (using 0-indexing).

Similarly you can use Boolean Array to Number to get the U16 value.

[ikhan123]

thanks, it worked!