Direct Hardware Control; Reading The Inputs; Reading The Outputs; Writing The Outputs - SeaLevel PLC-16.PCI User Manual

Direct Hardware Control

In systems where the user's program has direct access to the hardware (i.e. DOS) the table below gives the mapping
and functions that the PLC-16.PCI provides.
R = Read
W = Write
R/W = Read or Write
Function Available
R
R/W
FINDPCI.EXE is a utility used in the DOS environment to identify resources that have been assigned to the adapter
by the BIOS. It is found on the supplied Sealevel Software CD in the \software\seaio\Other\DOS directory. It will
display resources for each detected Sealevel Systems card in the system. These settings are also stored in the file
PCI.INI, located in the same directory as FINDPCI.EXE.
Each system motherboard organizes its physical PCI slots according to the current PCI specification. There is not a
fixed order or number of slots for each motherboard.
To determine which resources correspond to which PCI card, you may want to add the cards one at a time and run
FINDPCI.EXE after each card is added. Each PCI slot will have a corresponding BUS, DEVICE, and FUNCTION
number. These numbers uniquely identify that slot when running these DOS utilities. Note the slot data for each
card that you install.

Reading the Inputs

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 is applied it returns a zero on that bit.

Reading the Outputs

The relay ports return the ones complement of the value that is currently being used to drive the relays.

Writing the Outputs:

The output ports are the only ports that can be written. The relays on a standard PLC-16.PCI are normally open.
To close a relay a one must be written to the appropriate bit.
Sealevel Systems PLC-16.PCI
Port Address Hex
A 300 (Base + 0)
B 301(Base + 1)
C 302 (Base + 2)
D 303 (Base + 3)
Address Decimal
768 Input Port (Opto Input)
769 Not Used
770 Output Port (Reed Relays)
771 Not Used
Technical Description
Port Type
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