Ametek 7270 Instruction Manual page 210

Appendix E, ALPHABETICAL LISTING OF COMMANDS
PHA[.]
PHASEPOL [n]
PORTDIR [n]
READBYTE
REFMODE [n]
E-18
Signal phase
In fixed point mode causes the lock-in amplifier to respond with the signal phase in
centidegrees, in the range ±18000.
In floating point mode causes the lock-in amplifier to respond with the signal phase
in degrees.
Signal phase polarity control
n Function
Operation is the same as earlier SIGNAL RECOVERY lock-in amplifiers, such
0
as the models 7220, 7225, 7265, 7265, 7280, 5209 and 5210.
1 Operation is the same as earlier versions of firmware in the models 7270,
7124 and 7230
Digital port direction control
The value of n determines which of the eight lines on the digital port are configured
as inputs and which as outputs. The parameter n is a decimal number whose bit-wise
interpretation defines whether the corresponding line is an input or output. The line
is an input if the corresponding bit is a "1". For example:
n status
0 All lines configured as inputs
1 D0 = output, D1 - D7 = inputs
2 D1 = output, D0 and D2 - D7 = inputs
4 D2 = output, D0 - D1 and D3 - D7 = inputs
8 D3 = output, D0 - D2 and D4 - D7 = inputs
16 D4 = output, D0 - D3 and D5 - D7 = inputs
32 D5 = output, D0 - D4 and D6 - D7 = inputs
64 D6 = output, D0 - D5 and D7 = inputs
128 D7 = output, D0 - D6 inputs
255 All lines configured as outputs
Read digital port input
The response to the READBYTE command is an integer between 0 and 255
representing the binary value of all eight lines of the instrument rear panel digital
port. Hence, for example, if PORTDIR = 0 and the response to READBYTE is 255,
then all lines are high, and if the response to READBYTE is 0, then all lines are low.
Note that because the command does not differentiate between whether a line is
configured as an input or output, it can be used as a single command to determine the
present status of all eight lines, both inputs and outputs, of the port.
Reference mode selector
The value of n sets the reference mode of the instrument according to the following
table:
n Mode
0 Single Reference / Virtual Reference mode
1 Dual Harmonic mode
2 Dual Reference mode
NOTE: When in either of the dual reference modes the command set changes to
accommodate the additional controls. These changes are detailed in section 6.7.14