Command Descriptions; Signal Channel - Ametek 7230 Instruction Manual

6.7 Command Descriptions

6.7.01 Signal Channel

IMODE [n]
VMODE [n]
DEMOD2SRC [n] Second stage demodulator signal source
FLOAT [n]
FET [n] ]
This section lists the commands in logical groups, so that, for example, all
commands associated with setting controls which affect the signal channel are shown
together. Appendix G gives the same list of commands but in alphabetical order.
Current/Voltage mode input selector
The value of n sets the input mode according to the following table
n Input mode
0 Current mode off - voltage mode input enabled
1 High bandwidth current mode enabled - connect signal to B (I) input connector
2 Low noise current mode enabled - connect signal to B (I) input connector
If n = 0 then the input configuration is determined by the VMODE command.
If n > 0 then current mode is enabled irrespective of the VMODE setting.
Voltage input configuration
The value of n sets up the input configuration according to the following table:
n Input configuration
0 Both inputs grounded (test mode)
1 A input only
2 -B input only
3 A-B differential mode
Note that the IMODE command takes precedence over the VMODE command.
In the dual reference mode, the value of n sets the source of the signal for the second
stage demodulators according to the following table:
n Signal source
0 Main signal channel ADC (i.e. both demodulators are fed the same signal)
1 ADC1 - rear panel auxiliary ADC input
2 Demodulator 1 X channel output - this is the Tandem demodulation mode
Input connector shield float/ground control
n Selection
0 Ground
1 Float (connected to ground via a 1 k resistor)
FET input selection
The value of n controls the input device used at the signal input according to the
following table:
n Input device
0 Bipolar
1 FET
Chapter 6, COMPUTER OPERATION
6-9