User Manual 07507200
Model 720x
Page 12
O
peration Manual
Chapter 6
Programming
This section refers to the 7201 having a single 1x4 relay module. Other configurations are shown below.
The Model 7201 is a PXI register based card assembly design to be used with the National Instrument PXI
chassis. The Model 7201 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. This scenario verifies that the program register has correctly controlled the relay coil.
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 7201 is very simple. The module is organized as a 1x4 Coax RF Switch. 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: Bar0 + 0000h
coil read back: Bar0 + 0008h
Register Bit
15
14
13
12
11
10
9
8
Common Connected
To
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Register Bit
7
6
5
4
3
2
1
0
Common Connected
To
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Port 4
Port 3
Port 2
Port 1
NOTE : When NO bits are selected, the Common is connected to Port 1.
( See front panel on Assembly Drawing 91000160 for Port numbers)
