Manual 07507027
Model 7027
Page 12
O
peration Manual
Chapter 7
Programming
The Model 7027 is a PXI register based card assembly design to be used with the National Instrument PXI
specification. The Model 7027 can be programmed in 8, 16 or 32 bit wide data format. Through your PXI
controller, write the data to the appropriate register as shown on the register map for the relay or relays in the
register that is being closed. When the data bit is true, the relay chosen will be closed. The state of the relays
in a register can be determined by reading the desired register. Data read back represents the value of the
desired register. In addition, you can read back the coil state to verify that the coil is driven correctly by the
program register.
The register map is organized to show the relay designation in each register. It is followed by the register’s
functionality and the path connections to the front panel. PXI will automatically assign the starting address of
the card, called Bar0. This will be the starting address of the first register. Each address location controls 8
bits. Shown are the control functions using 16 format.
Programming of the Model 7027 is very straight forward. The module is organized as a quad 1x8 trees with
additional relays to combine the tree for 2 wire, 4 wire and 6 wire applications. The location of the first
register is assigned by the PCI enumerator. This is designated as “Bar0” or the starting address of the card.
The program registers using 16 bit format are located as follows:
Register #1 :
read/write function address
= Bar0 + 0000h
coil read back address
= Bar0 + 0008h
Register #2 :
read/write function address
= Bar0 + 0002h
coil read back address
= Bar0 + 000Ah
Register #3: read/write function address =Bar0 + 0004h
Coil read back address
=Bar0 + 000Ch
