i cannot read from the DELTA DVP28SV PLC registers?

hello everyone,
I'm using labview (very close to CITECT) to communicate with a DELTA DVP28SV PLC. I managed writing to a coil to to turn a fan on, and I also wrote to a register.
However, when i tried to read the coil (same coil i just turned on) or when i tried to read a register that im very sure has values (the register where i configure the modbus parameters), it would return ZERO, even when i tried to read the register that i just wrote into the reply was zero (I am sure that writing to the register was successful because i made the specific value that i wrote to the register a condition to turning a light on).

So, anyone knows why this could happen?? the Registers are Read/Write. I thought it could be that the scan time in the PLC is too short so i added delays but anything i read still gives zero back. ideas? can anyone help me with this?

here's the PLCs application manual in case it matters : http://www.delta.com.tw/product/em/control/plc/download/manual/DVP-PLC-Program_O_EN_20120416.pdf

btw regarding the coil, i gues it just turns on for a little amount of time that turns on the fan on some rising/falling ednge. but what i need to know is why i cant read the data register? I'd appreciate any help, especially a quick one~