Using Lookout to write a decimal point to an RTU in the field.

Question

Is thier a way to send an lookout exp.(ex.1.56) to a known writable register on an RTU out in the field. I am using the modbus object. I plan to send this expression that I have created to a series of regs. in the field and pull the info to a readable screen to display the converted readings from lookout. I want to use lookout to handle the complexed math and send it to the registers. EX. The RTU sends raw data (40003)to lookout. I convert it in an expression and I want to send it to reg(40501) out in the field. Question # 2. I also need to see if I can use a portable laptop in the field that mirrors the main host and is updated when the host updates. This is for the same application above. This is a mobile RTU
if you will. But as you move around in a 70 mile area repeaters change.

Answer 1

Hi,
It's not clear to me what exactly you mean by "you can't send two values to a register."
I am guessing you're trying to write a 32-bit floating point number. If this is the case, then here's how you would do it:
To write a 32-bit floating point value (decimal point), you will have to use the F registers. E.g., F40001. Lookout will then split the value into two 16-bit registers accoring to the IEEE floating point notation and write them in two consecutive registers.
Similarly, when you want Lookout to interpret two (consecutive) 16-bit registers in your PLC as a single 32-bit floating point number, you will use the F registers.
For a detailed description of all this please see the following two articles:
Detailed Descripti
ons of Lookout Accessing Floating Point Numbers/Registers in a Modbus PLC:
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/2de82ef20b2cc991862567f600432e33?OpenDocument
The Working Principle behind Reading Adjacent (32 Bit) D or F Registers of Modbus
http://digital.ni.com/public.nsf/websearch/4ef459f549fcc7028625660a000a7629?OpenDocument
I hope this is what you're looking for.
Regards,
Khalid