Calibration - Instrutech VGC-301 User Manual

Instruction Manual InstruTech VGC-301 Convection Vacuum Gauge Controller
SET SP1 ON and SET SP2 ON:
These setpoints correspond to the turn on points for each relay. The relays will turn on when the pressure drops
below this setting. [Factory default = 100 mTorr.]
SET SP1 OFF and SET SP2 OFF:
These setpoints correspond to the turn off points for each relay. The relays will turn off when the pressure rises
above this setting. [Factory default = 200 mTorr.]
SET ADDR:
This is the lower nibble of the one byte RS485 device address. (e.g. Setting this to a 5 would make the address
be 0x05 in hex; a 15 would be 0x0F in hex; if the address offset is equal to 0.) Note that Address must be used
even in RS232 commands. [Factory default = 1 ]
SET ADDR OFFSET
This is the upper nibble of the one byte RS485 address. (e.g. Setting this to a 5 (with ADDR = 0) would make the
address 0x50, a 15 would be 0xF0.) [Factory default = 0.]
SET BAUD
This sets the baud rate for the RS485 and the RS232. The baud rate can be set to many other values through
the serial interface command set. The parity can also be changed. When this occurs, the current setting will be
shown in the list of choices and can be re-selected if changed. [Factory default = 19.2K baud]
RS485 TYPE
Select 2-wire or 4-wire configuration for the RS-485 interface.
SET ANALOG
Selects non-linear, linear, or log-linear for the analog output.
SET LINEAR
This will take the user to 4 screens to setup the linear analog output.
a) Set the minimum pressure,
b) Set the minimum voltage corresponding to the minimum pressure.
c) Set the maximum pressure.
d) Set the maximum voltage corresponding to the maximum pressure.
The linear output voltage can be any values between 10mV and 10V corresponding to pressure values between 1
mTorr and 1000 Torr. [Factory default is 10mV to 10 Vdc corresponding to 1 mTorr to 1 Torr.]
INFO
This screen shows the Instrutech phone number for questions and the unit software version.

Calibration:

All InstruTech gauges are calibrated prior to shipment using Nitrogen. However, you can calibrate the VGC-301
against your own standards, using the zero and span settings, as described above. Zero and span affect the
displayed pressure values and the output signals. Care should be exercised when using gases other than
nitrogen N - See Appendix B for more information.
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