ADLINK Technology PCI-7251 - Control and Status Registers Map; Relay Output and Readback Registers

16 •• Register Format
3.2 Control and Status Registers Map
The control of the relays and status of the isolation input is by means
of registers. The PCI-7250 and three PCI-7251 expansion boards
occupy 8 I/O address. Table 3.1 shows the registers‘ description and
offset address relative to the base address. If the expansion PCI-7251
boards is not installed, the corresponding registers are not used and
meanningless.
Offset Write Read Board
0 Relay Output Isolation Input PCI-7250
1 not used Output readback
2 Relay Output Isolation Input PCI-7251 #1
3 not used Output readback
4 Relay Output Isolation Input PCI-7251 #2
5 not used Output readback
6 Relay Output Isolation Input PCI-7251 #3
7 not used Output readback
Write Read Board
0 Relay Output Isolation Input
1 not used not used cPCI-7252
2 not used Output readback
Table 3.1 The register offset and the functions
3.3 Relay Output and Readback Registers
There are 8 relays on each PCI-7250 / 7251 and cPCI-7252 board.
Each relay are controlled by one bits of the control register. The bit
value ‘0’ means the relay is not excited. The normal open signal line is
‘open’ with the common line and the normal closed signal line is
connected with the common line. The bit value ‘1’ means the relay is
excited and the normal open signal line is now closed, and vise versa.
The initial bits values of the control register are all ‘0’. And the status
of the relay can be readback from the readback register. If the relay is
open, the corresponding bit value is ‘0’. If the relay is closed, the bit
value is ‘1’.