3-2
3
which in turn will set bits in the Status Byte Register. If the corresponding
Status Byte Enable bits are set, then Service Request bit will be set and
generate an SRQ. The user can serial poll or query the Status Byte to
determine the source of the SRQ and take the appropriate action.
The six Relay Drivers are active low outputs that are individually controlled
by commands received from the GPIB bus or Serial interface. The drivers
are open collector transistors that sink up to 300 mA.
The four Analog Outputs are user programmed over a 0 to 5 Vdc range by
commands received from the GPIB bus or Serial interface. The unit uses a
linear equation, Vout = M * Vcmd + B, to transform the commanded value
to the output voltage. The M and B values can be programmed to scale the
command to match the controlled variable. The user can also program a
Limit value to restrict the output voltage. Commands in excess of the limit
value are not executed and set the Command Execution Error bit in the ESR
Register.
The six Analog Inputs have four programmable ranges for converting
analog inputs to digital values. Each channel may be set to a
±
10,
±
5, 0 to
+10 or 0 to +5 volt range. The ranges are selected by individually
programming the RANGe and POLarity command settings for each channel.
The analog inputs are continuously sampled and averaged to reduce the
affect of noise on the measured value. The current average value is
converted and outputted in response to the user's MEASure:VOLTage?
command. The averaging value is programmable for each channel and is
factory set to reject 60 Hz noise. The user can also modify the factory gain
and offset calibration values to scale the analog inputs to match the
measured parameter.
The four Temperature Inputs sense the output from Type J thermocouples
to measure the external temperature over a -100
°
C to + 400
°
C range. The
temperature inputs are continuously sampled and averaged to reduce the
affect of noise on the measured value. The current value is converted and
outputted in response to the MEASure:TEMPerature? command. The
averaging value is programmable for each channel and is factory set to reject
60 Hz noise.
The units use SCPI commands which are a subset of the Standardized
Commands for Programmable Instruments Standard. The advantage of the
