MKS 247D - Scaling Control Potentiometer Adjustment

Scaling Controls Cha
p
ter Three: Overview
48
Scaling Control Potentiometer
The Scaling Control (refer to Figure 7) is a 10-turn potentiometer that serves as a voltage divider
for the +5 VDC output signals from the MFCs; the control has a full scale setting of 1000.
1
0
10
30
20
40
50
60
70
80
90
Window
Ad
j
ustment Knob
Slide Lock
Outer Control
(
Sets factors of 100
)
Inner Control
(
Sets factors of 10
)
Figure 7: Scaling Control Potentiometer - Initial Setting
The outer control represents factors of 100; indicated by the numbers 0 to 10 which display in the
window at the top of the potentiometer. The inner control represents factors of 10, in divisions
of 2; these values are set when the appropriate value is aligned with the vertical line beneath the
window. The adjustment knob cannot be turned below 0 or above the full scale setting of 1000.
Note
Since the maximum number of counts the digital panel meter can read is
1999, the voltage cannot exceed 2 VDC. That is, the maximum value
that can be displayed in the scaling potentiometer window is 2.
To adjust the Scaling Control Potentiometer:
•
Unlock the slide lock on the right side of the control by pushing it up (counterclockwise)
•
Turn the adjustment knob
clockwise
to increase the value represented on the control
The 147 unit is typically shipped with the control set to “100”, as shown in Figure 7.
•
Turn the adjustment knob
counterclockwise
to decrease the value represented on the
control
•
Lock the position of the control by pushing the slide lock on the right side of the control
down (clockwise)
Note
Refer to
How To Setup the System
, step 7, page 57, for more information
and an example Scaling Control Potentiometer adjustment.