Technical data

Publication No. 980824-118 Rev. A 1260-118/-118A User Manual

Astronics Test Systems Module Operation 3-5

Table 3-2, 1260-118A Control Register Channel Assignments

Control

Channels

Bit 7

(MSB)

Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1

Bit 0

(LSB)

unused

For the 1260-118 setting a control bit to 1 closes the corresponding

channel, and clearing the bit to zero opens the corresponding

channel. Thus, if you write the value 1000 0101 binary = 133

decimal = 85 hexadecimal to Control Register 0

, channels 0, 2,

and 7 will close, while channels 1, 3, 4, 5, and 6 will open.

Unlike the 1260-

118, not all bits in the control registers are used.

Thus, for the 1260-118A if you write the value 1000 0101 binary =

133 decimal = 85 hexadecimal to Control Register 0, only channel

1 will close, while channels 0 and 2 will open.

The present control register value may be read back by reading an

8-bit value from the control register address.

The value is

inverted. In other words, the eight-bit value read back is the one’s

complement of the value written. If an unused bit in the control

If you want to change the state of a single relay without affecting

the present state of the other relays controlled by the control

1. Read the control register

Invert the bits (perform a one’s complement on the register

data)

3. Perform a bit-

wise AND operation, leaving all but the specific

control register bit for the relay to change

4. To open: continue to step 5. To close: OR in the bit for the