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1260-132 User Manual
Module Operation 3-7
The present control register value may be read back by reading an
8-bit value from the control register address.
The value is
inverted from the control register .
In other words, the eight-bit
value read back is the one’s complement of the value written.
If you want to change the state of a single relay without affecting the
present state of the other relays controlled by the control register,
you must:
1. Read the control register.
2. 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
: No operation required.
To close
: OR in the bits
for the relays to close.
5. Write the modified value back to the control register.
For example, to close channel 14:
1. Read Control Register 1 (this register controls channels 8
through 15, with channel 8 represented by the LSB).
2. Invert the bits in the value read in step 1.
3. AND with 1011 1111 binary (the zero is in the position
corresponding to channel 14).
4. OR with 0100 0000 binary.
5. Write the value to Control Register 1.
The VISA I/O library may be used to control the module. The VISA
function
viOut8()
is used to write a single 8-bit byte to a control
register, while
viIn8()
is used to read a single 8-bit byte from the
control register. The following code example shows the use of
viOut8()
to update the 1260-132 module.
Summary of Contents for 1260-132
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