I am trying to use free driver from Sapia or mbServer to do a very easy application that must read some registers from a ModBus Device.
The address I have to read can be 408307 or similar, and the first 4 is the method 4 "read Input Register". I can use only that.
The problem is that the address is 8307 but my device, that is working perfectly with Modicon drivers, must work with a cheap driver.

How I can use the above mentioned drivers to do it?

Using Sapia :
SMRX1.MbReadInputRegs(1, 8307, 1, nRegData(0))
Don't works and give me Illegal Function Error.

Thanks to all who wants to help me.
Stblack

 

Download the free evaluation version of Automated Solutions' Modbus ActiveX Control to very proper operation. Six digit addressing is supported. The evaluation version runs for 30 days.

http://www.automatedsolutions.com

 

Thanks I will try it.

But the problem still remains, because I have to produce a very easy application using a free driver. The product I am selling it costs around 150-200 Euro, and I can't use an expensive driver.

I will check the price with automatedsolutions.

Stblack

 

Automated Solutions' ActiveX Controls are runtime-free (some restrictions may apply, check with us to verify). You purchase the development kit one time and there are no ongoing runtime fees for distribution with your application.

If you meet the runtime-free requirement, there would be no additional cost to use our driver in your application.

 

Check http://members.tripod.com/~mbserver/
Is a free ActiveX control and seems to work very nice.

 

Just an educated guess, but 4x08307 is a HOLDING REGISTER, not an INPUT REGISTER.

I'd guess your call above is trying to read 3x08307 not 4x08307. If the slave does NOT support input registers (as many do not) you'll get an illegal function exception response.

best regards
- LynnL