Sierra Instruction Manual Smart-Trak
®
2 Series 100
87
Appendix F: Micro-Trak
The information included in this section applies to the Model 101 Micro-Trak mass flow
meters and controllers only.
Introduction
The Micro-Trak series of flow instruments from Sierra are designed to measure and
control ultra low flows of clean gas. Special considerations must be taken to obtain
optimum performance from your Model 101 Micro-Trak instrument.
Installation
Because the gas flows used with Micro-Trak are extremely small, the plumbing of these
instruments has a dramatic impact on their performance. Sierra recommends all
installations use tubing of 1/8 inch diameter or smaller. Larger tubing may be used, but a
reduction in the response time of the instruments may be noticed. It is also important to
minimize large volumes within the gas systems because these will act as manifolds and
introduce delays in flow measurement and control.
Micro-Trak must be securely mounted in a location away from vibrations or it may not
function normally. Periodic impacts will upset the delicate equilibrium of Micro-Trak
and should be avoided.
Any gas used with Micro-Trak must be extremely clean and dry so it does not
contaminate the micro passages inside the instrument. An upstream 10 micron particle
filter coupled with water and oil traps are suggested.
Inlet gas pressure must be very well regulated for optimum performance from Micro-
Trak. The M101 flow meter can be over-ranged by a pressure change of 10 in H
2
0 (0.36
psi or 25 mbar). The C101 flow controller can temporarily lose control over a similar
pressure fluctuation. In either case, the Micro Trak will recover within several seconds,
but a delicate process could be affected. For these reasons, caution must be taken to
maintain stable pressure to obtain the excellent performance Micro-Trak was engineered
to deliver.
Electrical installation is identical to other 100 Series instruments. See Chapter 2 for
details.
Operation
Operation of Micro-Trak is similar to all other 100 Series instruments outlined in this
manual. All functions of the Smart-Trak 2 will function with Micro-Trak and can be
used with analog or digital signals, per the instructions in Chapters 3, 4 and 5.