Technical Description
Sealevel Systems
DIO-32B
Page
11
Direct Hardware Control
In systems where the users program has direct access to the hardware (DOS)
the table below gives the mapping and functions that the 3093 provide, a base
address of 300 was used. If a different base address is used then the port
addresses are calculated as shown in the table.
Reading the Inputs (direct) :
The inputs are active Low. If no voltage is applied across one of the
differential inputs it returns a one on that bit. If an AC or DC voltage (of
sufficient magnitude, covered above) is applied it returns a zero on that bit.
Reading the Outputs (relays) (direct) :
The relay ports return the ones complement of the value that is currently being
used to drive the relays. When using the API the value is returned not the
complement of the value.
Writing the Outputs (relays) (direct) :
The output ports are the only ports that can be written. The relays on a standard
3093 are normally open. To close a relay a one must be written to the
appropriate bit.
R = Read
W = Write
R/W = Read or Write
Function
Available
Port
Address Hex
Address
Decimal
Port Type
R
A
300 (Base + 0)
768
Input Port (Opto Input)
R
B
301(Base + 1)
769
Input Port
R/W
C
302 (Base + 2)
770
Output Port (Reed Relays)
R/W
D
303 (Base + 3)
771
Output Port