Impulse 8011 User Manual
Page 11
© Sealevel Systems, Inc.
- 9 -
PLC-16.PCI User Manual
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 binary one (1) must be written to
the appropriate bit.
Reading the Outputs
The relay ports can also be read to determine the status of the various relays. A read
will return the ones complement (or opposite) of the value that is currently written to
the port.
Register Description
All ports are set to input after reset or power up.
Address Mode D7
D6
D5 D4 D3 D2 D1 D0
Base+0
RD/WR PAD7 PAD6 PAD5
PAD4
PAD3
PAD2 PAD1
PAD0
Base+1
RD
{0}
{0}
{0}
{0}
{0}
{0}
{0}
{0}
Base+2
RD/WR PCD7 PCD6 PCD5 PCD4 PCD3 PCD2 PCD1 PCD0
Base+3
RD
{0}
{0}
{0}
{0}
{0}
{0}
{0}
{0}
Base+4
RD
{0}
{0}
{0}
{0}
{0}
{0}
{0}
{0}
Base+5
RD/WR
IRQEN
IRQST
{0} {0} {0} {0} IRC1
IRC0
Base+6
RD
{0}
{0}
{0}
{0}
{0}
{0}
{0}
{0}
Base+7
RD
{0}
{0}
{0}
{0}
{0}
{0}
{0}
{0}
Interrupt Control
When enabled, interrupts are generated on Port A bit D0.
IRQEN
Interrupt enable
1 = enabled
0 = disabled ( 0 on power up )
IRC0
IRC1
Interrupt mode select, see table below
Interrupt mode select, see table below
Interrupt Mode Select Table
Interrupt source is Base+0 bit D0. When selecting the Interrupt Type, always disable
interrupts prior to changing or setting states. This will help prevent inadvertent or
unexpected interrupts from occurring.
IRC1 IRC0
Interrupt
Type
0 0 Low
Level
0 1
High
Level
1 0
Falling
Edge
1 1
Rising
Edge
Warning: When using the High and Low Level interrupts, an interrupt occurs when
input D0 changes to either a High or Low state. This will cause the computer to
remain in an interrupt state until the input state changes.
Interrupt Read
Reading the Interrupt Status port (Base+5) clears any interrupt pending.
IRQST
(D0) Interrupt Status
1 = interrupt pending, 0 = none