3. Functionality
647C
16
3.3 The EXTENDED DISPLAY menu
MGC 647C V3.0
CH1 CH2 CH3 CH4
ACT.FLOW 0.000 1.750 1.400 0.000
SETPOINT 4.500 1.750 1.400 0.728
UNIT SCCM SCCM SLM SLM
RANGE FS. 5.000 5.000 1.4000 1.450
GAS USER AIR CO He
2
MODE INDEP. INDEP. INDEP. SLAVE
STATUS OFF ON ON ON
PRESSURE 0000.0 mbar
00 ERRORS FLOW ON INPUT DIRECT
Figure 7
The EXTENDED DISPLAY menu allows controlling the system before and during operation. It
contains the most important information needed to control the system.
Here the setpoints of all channels can be set and changed. The setpoints are selected by using the
cursor keys. The input is done either numerically by typing in the values or by scrolling using the
cursor keys. If MEMORY is displayed in the INPUT field of the status line, a predefined gas menu
has been selected in the previosly described USER DISPLAY menu. In this case the set points of
the channels cannot be changed.
Due to instabilities at the lower end of MFC range, the lowest setpoint is limited to 1%. Setpoints
less than that are displayed as zero and an output value of –0.5 V is transferred to the MFC.
The displayed full scale ranges (RANGE FS.) are the ranges of each controller scaled with the gas
correction factors. E.g. channel 4 controls a MFC with a range of 1 slm, calibrated in nitrogen. The
regulated gas is helium and has a correction factor of 1.450 with respect to the calibration gas
nitrogen, i.e. the actual full scale range is: RANGE FS. = 1 * 1.45 = 1.45 slm.
The actual gas flow of each channel is displayed in the line ACT.FLOW. Here the correction factors
and ranges of the selected gases are also automatically taken into account. Values higher than
110% are displayed as an overflow through dashes: “-.---“. The lowest displayed flow value is –
10%. (See also Zero Adjust).
Typing <ON><x> turns on the valve of channel x and causes its set point to be sent to the mass
flow controller. In addition to provide the possibility of turning on and off all controllers at the same
time, there is the switch <ON/OFF><ALL>.