On 5/15/2013 12:48 AM, Todd Zuercher wrote: > I have a Modbus question. I hope there are some Modbus gurus listening. > > I am trying to use mb2hal to control a bunch of VFDs on a gang router . > I have successfully gotten mb2hal to communicate with the drives but... > > Several of the registers of these drives use a format of "A chain of two 8 > bit unsigned integers" to quote the manual. > Basically the drive is using 1 register to write two different pieces of > data. The mb2hal component is writing both of these data points to a single > s32 pin. How do I separate this into the two numbers I can use. Is there a > component that can divide an s32 into 4 u8 numbers? Would I then have to > change the 2 u8 numbers I need back to u32 numbers to be able to use them for > anything? > > I've also asked the question here. > http://www.linuxcnc.org/index.php/english/forum/25-classicladder/26456-modbus-examples?start=30#34112 > A pdf copy of the drives manual is attached to the first post of the thread. > >
You would be better off staying away from 8 bit data. As I recall just about every thing that Modbus does is either bits or 16 bit registers. If you have an option, which I think you do, stick with bits or 16 bit registers. Everything else will be more difficult. You can always make a custom hal component if you want to go that route. Look at some of the existing components source code and read the manual. It isn't very difficult, but I doubt that is the best solution to your situation. Dave Cole ------------------------------------------------------------------------------ AlienVault Unified Security Management (USM) platform delivers complete security visibility with the essential security capabilities. Easily and efficiently configure, manage, and operate all of your security controls from a single console and one unified framework. Download a free trial. http://p.sf.net/sfu/alienvault_d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
