B&B Electronics MODSCAN32 - Manual - Manual (Page 84)

84
Mobuss OCX Implementation Notes
The following notes present programming details concerning operation of the Modbuss Data Control.
if Update() returns TRUE
guaranteed to get an UpdateFinished Event
NOT guaranteed to get Ready Event.
if Update() returns FALSE
UpdateFinished is NOT fired.
Update() may return FALSE under the following conditions:
DEMO_TIME_EXPIRED
OUT_OF_BUFFERS
OCX_OVERRUN
INVALID_PORT_DESIGNATION
INVALID_SLAVE_ADDRESS
INVALID_DATA_ADDRESS
INVALID_DATA_LENGTH
OCX_HELPER_FAILURE (MbOCXsvr Not Running)
If EnableBlockWrites is FALSE
Setting a data value, (modbuss1.register(0) = 1),
does NOT change the value of the data within the control.
if modbuss1.register(0) = 0 then
modbuss1.register(0) = 1
Text1.Text = modbuss1.register(0)
endif
'Text1.Text will be 0
Setting a data value instructs the control to issue a
write command to the designated slave device.
The data within the control will not be updated until
the next Update() request.
The control will automatically request the Update()
after receiving the write message acknowledgement
from the slave, (regardless of the success indication).