Teledyne 40, Power Supply Page 12, Channel Switch Selection Decimal Position, 3.2 Correction Factor:

Page 12

or supply a 5-volt dummy signal to the FLOW -OUT terminals on the back panel. Turn the DIS-

PLAY-ADJUST potentiometer for the channel to be set until the displa y reads the desired full scale

reading. The DISPLAY-ADJUST potentiometers are located on the PC board near the front/center

as shown in Fig3.1. Channel 1 is on the right when looking from the front of the Power Supply.

Remove the two screws that hold the aluminum perforated upper cover in place. Slide te cov e

out. The dipsSwitches are located beind the CHANNEL SELECTOR switch ( see Fig 3.2). Turn

on the desired point for a particular channel by pressing its respective dipswitch down towards the

channel number (OPEN indicates that the switch is off). Switches 1 and 2 are for Channel 1Switches 1 and 2 are for Channel 1

Switches 1 and 2 are for Channel 1Switches 1 and 2 are for Channel 1

Switches 1 and 2 are for Channel 1

(Switch 1 provides 2 places to the right of the decimal point, and Switch 2 provides 1 place to the

right of the decimal point). Switches 3 and 4 are for Channel 2Switches 3 and 4 are for Channel 2

Switches 3 and 4 are for Channel 2Switches 3 and 4 are for Channel 2

Switches 3 and 4 are for Channel 2 (Switch 3 provides 2 places to the

right of the decimal point, and Switch 4 provides 1 place to the right of the decimal point).

Switches 5, 6, 7, 8 are used for channels 3 and 4 in the same fashion (see Figure 3.2 and table "A"

on page 7 for examples).Reinstall cover if no further modifications are needed.

Channel Switch Selection Decimal Position

1 ....................................... 1............................................................... xx.xx

......................................... 2 ............................................................... xxx.x

2 ....................................... 3............................................................... xx.xx

......................................... 4 ............................................................... xxx.x

3 ....................................... 5............................................................... xx.xx

......................................... 6 ............................................................... xxx.x

4 ....................................... 7............................................................... xx.xx

......................................... 8 ............................................................... xxx.x

3.2 Correction Factor:

Normally mass flowmeters are calibrated using a standardized volumetric unit as a unit of mass,

for example a standard liter is a liter of the gas at 760 Torr and 0oC. Thermal mass flowmeters

measure gas flow by monitoring this heat capacity is constant, but it varies from gas to gas. If a

different gas is measured than the gas for which the flowmeter is calibrated, the flowmeter will have

a different mass flow through it in volumetric units for the same voltage output. This difference in

volumetric mass flow for the different gases is due to every gas having a different heat capacity.

Under normal situations the gases will respond as ideal gases and this difference in flow can be

Some components on the PC Board are at High High

High High

High VV

Voltage,oltage,

oltage,oltage,

oltage,

only qualified personnel

should perform this test..