INFICON STM-100/MF Thin Film Deposition Monitor - Manual (Page 56)

COMPUTER INTERFACING
The STM-100 / MF can be connected to a computer in a variety of ways. An
RS-232 interface is standard, and either an IEEE or BITBUS interface can be
added as an option. There is room for only 1 optional communications card. If
you purchase a communications option and need to install it, see Section 3.8. For
the RS-232 interface, either a SECS-II or standard Sycon protocol can be
selected. This section will describe the hardware with each interface, and give an
example of how to interface to an IBM-PC.
RS-232 INTERFACE
RS-232 is an electrical specification for the transmission of data in a serial
format. What this means is that the mechanism for transmitting data is defined by
RS-232. The particular set of commands is defined by each vendor as they see
fit. There is no computer program that will communicate with all RS-232 devices.
Different sets of commands and miscellaneous overhead must be handled
differently. An example would be as if you were to call someone in a foreign
country. Just because you can establish the link (the telephone) does not mean
that you can communicate. Both parties must speak the same language. For this
reason the SEMI institute has devised a protocol that allows different vendors of
semiconductor processing equipment to "talk" RS-232 in a consistent manner.
Unfortunately, because of the wide variety of situations that SECS-II will handle, it
is a complicated protocol. The SECS-ll protocol provided in each Sycon
instrument is a sub-set of the full implementation, thus it is simpler and easier to
install than the full implementation of SECS-ll. It is selected by setting the
CONFIGURATION dip switch on the back of the instrument. This is shown in
Table 5.1.
BAUD RATES and CABLING
No matter what protocol you are using, the first order of business is to get the
STM-100 / MF connected to your computer and set up the baud rates. Figures
5.1a and 5.1b shows how to connect to an IBM-AT and IBM-PC. Note that the
connectors are different for each type of computer.
STM-100 / MF
9 PIN MALE
SHIELD
9 PIN FEMALE
IBM-AT
2 RxD
3 TxD
9
5 GND
DSR 6
RxD 2
TxD 3
CTS 8
DTR 4
GND 5
Figure 5.1: Cable Connection From STM-100 / MF to IBM-AT.
SECTION 5.1
RS-232 Description
Making an RS-232
Cable
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