300 VT1422A Command Reference Chapter 7
INPut

INPut:GAIN

INPut:GAIN <gain>,(@<ch_list>) sets the channel gain on programmable amplifier
SCP or RSCU.
Note An important thing to understand about input amplifier SCPs and RSCUs is that given
a fixed input value at a channel, changes in channel gain do not change the value
returned from that channel. The DSP chip (Digital Signal Processor) keeps track of
SCP gain and A/D range amplifier settings and "calculates" a value that reflects the
signal level at the input terminal. The only time this in not true is when the SCP gain
chosen would cause the output of the SCP amplifier to be too great for the selected
A/D range. As an example, with SCP gain set to 64, an input signal greater than
±0.25 volts would cause an over-range reading even with the A/D set to its 16 volt
range.
Parameters

Comments •A programmable amplifier SCP or RSC has a choice of several discrete gain

settings. The gain set will be the one closest to the value specified by <gain>.
Refer to the SCP manual for specific information on the SCP being
programming. Sending MAX will program the highest gain available with the
SCP installed. Sending MIN will program the lowest gain.
•Sending a value for <gain> that is greater than the highest or less than the lowest
setting allowable for the SCP will generate a -222 "Data out of range" error.
•When Accepted: Not while INITiated
•Related Commands: INP:GAIN?
•*RST Condition: gain set to MIN
•Send with VXIplug&play Function: hpe1422_cmd(...)
Usage INP:GAIN 8,(@100:119) Set gain of 8 for first 20 channels
INPUT:GAIN 64,(@155) Set gain of 64 for SCP channel 55
Parameter
Name Parameter
Type Range of
Values Default
Units
gain numeric (float32)
discrete (string) see comment |
MIN | MAX none
ch_list channel list(string) 100 - 163 none