Instrutech Super Bee CVM201 User Manual

Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 18
7 Analog Output
The CVM201 provides either a non-linear or a
log-linear analog output. Additionally it can provide
a linear 0-10 Vdc analog output.
Non-Linear Output
The first Convectron® gauge controllers produced a non-
linear output signal of 0.375 to 5.659 Vdc for 0 to 1000
Torr of N
2
, roughly in the shape of an "S" curve, as shown
at right. Granville-Phillips® adopted the same output
curve for most of their Mini-Convectron® modules and
controllers with non-linear output (although in recent
years, some Granville-Phillips® controllers may output
variations of the original S-curve).
The non-linear output from InstruTech convection
gauges, modules and controllers duplicates the original
S-curve of 0.375 to 5.659 Vdc for 0 to 1000 Torr.
The tables shown in section 7.1 and 7.2 contain the
lookup data for converting the non-linear output voltage
into pressure values for nitrogen and various other gases.
Log-Linear Output
Many InstruTech modules and controllers also provide a
log-linear output signal, as an alternative to the non-
linear signal described above. This output, shown at
right, is a 1 Volt per decade signal that may be easier to
use for data logging or control.
The table shown in section 7.3 and 7.4 contain the lookup
data and provides the formulas for converting the
log-linear output voltage into pressure values for
nitrogen and various other gases.
Linear 0-10 Vdc Analog Output
The CVM201 also provides a linear 0-10 Vdc analog output. The linear output voltage can be any value between 10
mV and 10 V corresponding to displayed pressure between 1 mTorr and 1000 Torr. However, the useful range of the
linear analog output is three decades. For example if the minimum pressure selected is 1 mTorr (1.0 x 10
-3
Torr) with
a corresponding minimum voltage output of 0.01 volts, then maximum pressure selected to correspond to a
maximum voltage output of 10 volts should not exceed 1.0 Torr. If your application requires the analog output to
cover a pressure range exceeding three decades then consider using the non-linear or the log-linear analog output.
Note that an analog output of less than 0.01 volts (to near 0 volt) may indicate a damaged or faulty sensor.
Non-Linear Analog Output
10
+3
10
-3
10
-2
10
-1
10
0
10
+1
10
+2
1
2
3
4
5
6
Pressure - Torr
Output - Volts
Non-Linear Analog Output
10
+3
10
-3
10
-2
10
-1
10
0
10
+1
10
+2
1
2
3
4
5
6
Pressure - Torr
Output - Volts
10
+3
10
-3
10
-2
10
-1
10
0
10
+1
10
+2
1
2
3
4
5
6
Pressure - Torr
Output - Volts
10
+3
10
-3
10
-2
10
-1
10
0
10
+1
10
+2
2
3
4
5
6
7
8
Pressure - Torr
Output - Volts
Log-Linear Analog Output
1
10
+3
10
-3
10
-2
10
-1
10
0
10
+1
10
+2
2
3
4
5
6
7
8
Pressure - Torr
Output - Volts
Log-Linear Analog Output
1

Instrutech Super Bee CVM201 Specifications

General

Brand	Instrutech
Model	Super Bee CVM201
Category	Measuring Instruments
Language	English