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SEMI E30-1103 © SEMI 1992, 2003 25 4.2.3.5 Scenario Host Initiates Trace Report: COMMENT HOST EQUIPMENT COMMENT Trace Data initialization requested S2,F23--> <--S2,F24 Acknowledge, trace initiated [DO] TOTSMP REPGS…

SEMI E30-1103 © SEMI 1992, 2003

4.2.2.5 Scenario

Host Requests Report:

COMMENT HOST EQUIPMENT COMMENT

Host requests data variables

contained in report RPTID S6,F19-->

<--S6,F20 Equipment responds with a list of

variable data for the given

RPTID.

4.2.3 Trace Data Collection

4.2.3.1 Purpose — Trace data collection provides a

method of sampling data on a periodic basis. The time-

based approach to data collection is useful in tracking

trends or repeated applications within a time window,

or monitoring of continuous data.

4.2.3.2 Definitions

Data Sample Period (DSPER) — The time delay

between samples. See SEMI E5 for a full definition of

this data item.

Reporting Group Size (REPGSZ) — The number of

samples included per trace report transmitted to the

host. See SEMI E5 for a full definition of this data item.

Status Variable (SV) — Status data item (included in

trace report). See SEMI E5 for a full definition of this

data item.

Status Variable ID (SVID) — A unique identifier of a

status variable. See SEMI E5 for a full definition of this

data item.

Total Samples (TOTSMP) — Number of samples to be

taken during a complete trace period. See SEMI E5 for

a full definition of this data item.

Trace Request ID (TRID) — An identifier associated

with a trace request definition. See SEMI E5 for a full

definition of this data item.

4.2.3.3 Detailed Description — The equipment shall

establish a trace report as instructed by the host

(S2,F23). For a trace report (S6,F1), the host shall

designate a name for the trace report (TRID), a time

interval for data sampling (DSPER), the total number of

samples to be taken (TOTSMP), the number of samples

per trace report (REPGSZ), and a listing of which data

will be sent with the report (SVID’s). The number of

trace reports sent to the host is determined by total

samples divided by reporting group size

(TOTSMP/REPGSZ).

The equipment shall sample the specified data (SV’s) at

the interval designated by the host (DSPER) and shall

send a predefined trace report to the host for the

specified reporting group size (REPGSZ). The trace

report definition shall be automatically deleted from the

equipment after the last trace report has been sent.

The host may modify or re-initiate a trace function

currently in progress by specifying the same TRID in a

trace request definition, at which point the old trace

shall be terminated and the new trace shall be initiated,

or the host can instruct the equipment to terminate a

trace report prior to its completion by specifying

TOTSMP = 0 for that TRID, at which point the trace

report definition shall be deleted.

A detailed example is included as Application Note

A.4.

4.2.3.4 Requirements

— The equipment must have a local mechanism (e.g.,

internal clock) for triggering the periodic sampling

and transmission of trace reports to the host.

— A minimum of four (4) concurrent traces shall be

supported by the equipment. The same SVID may

be collected in multiple traces simultaneously.

— All SVID’s available at the equipment shall be

supported for trace data collection. The exception to

this is any SV that will not fit into a single block.

NOTE 5: SEMI E5 provides for SV’s to be of a list format.

Since this may in practice be a variable list, there is a

potential problem with such an SV supported by the Trace

Data Collection capability. This is a problem with the SEMI

E5 standard. Care should be exercised in the use of SV’s

using the list format.

SEMI E30-1103 © SEMI 1992, 2003

4.2.3.5 Scenario

Host Initiates Trace Report:

COMMENT HOST EQUIPMENT COMMENT

Trace Data initialization

requested S2,F23-->

<--S2,F24 Acknowledge, trace initiated

[DO] TOTSMP REPGSZ times

[DO] REPGSZ many times: collect

SVID

,...SVID

data, delay

time by DSPER.

[END_DO]

<--S6,F1 Send SV

,...SV

Acknowledge receipt S6,F2-->

[END_DO]

Optional:

Request trace termination prior to

completion (TOTSMP = 0) S2,F23-->

<--S2,F24 Acknowledge premature termination

4.2.4 Limits Monitoring — This capability relates to the

monitoring of selected equipment variables and has

three primary aspects:

— Defines a standard set of monitoring zones and

limits.

— Provides for reporting to the host when selected

equipment variables transition between monitoring

zones.

— Empowers the host to modify the values of the

variable limit attributes for these same selected

equipment variables.

4.2.4.1 Purpose — The limits monitoring capability

provides the host a means of monitoring equipment

conditions by a flexible, efficient, and asynchronous

method which is consistent across equipment. It

eliminates the need for constant polling of equipment

by the host for current status values. Further, this

capability allows the host to implement changes in the

monitoring range as needed. This capability has

application to both production operation and

diagnostic/testing scenarios, and it also has applicability

to statistical process control.

4.2.4.2 Definitions

LimitVariable — DVVAL containing the VID of a

specific equipment variable for which a zone transition

collection event has been generated.

EventLimit — DVVAL containing the LIMITID of the

limit crossed by LimitVariable.

TransitionType — DVVAL which defines the direction

of the zone transition which has occurred: 0 = transition

from lower to upper zone, 1 = transition from upper to

lower zone.

Limit — Used in this section to represent the set of

variable limit attributes that completely describe a

variable monitoring “barrier.” The attributes include

VID, Units, UPPERDB, LOWERDB, LIMITMAX, and

LIMITMIN. In some contexts it may be interpreted

more narrowly as the combination of UPPERDB and

LOWERDB.

LIMITID

— Refers to the identifier of a specific limit

(as defined by UPPERDB and LOWERDB) among the

set of limits for a monitored equipment variable.

LIMITIDs are consecutively numbered, beginning at

one through the number of limits possible (seven

minimum).

Monitoring Zone — A subset of the possible range of

values for a variable of interest to the host. A single

limit divides the range into two zones. Multiple limits

may be combined to divide the range even further.

Zone Transition — The movement of a variable value

from one monitoring zone to another. This transition is

a collection event and has a corresponding CEID.

Deadband — An overlap of two zones implemented to

prevent constant zone transitions by a variable sitting

on or near a limit (i.e., “chattering”).

UPPERDB — A variable limit attribute that defines the

upper boundary of the deadband of a limit.

The value

applies to a single limit (LIMITID) for a specified VID.

18 The format and units must be the same as the format of the

variable being monitored.

SEMI E30-1103 © SEMI 1992, 2003

Thus, UPPERDB and LOWERDB as a pair define a

limit.

LOWERDB — A variable limit attribute that defines the

lower boundary of the deadband of a limit.

The value

applies to a single limit (LIMITID) for a specified VID.

Thus, UPPERDB and LOWERDB as a pair define a

limit.

UPPER ZONE — The range of values lying above a

limit.

LOWERZONE — The range of values lying below a

limit.

LIMITMAX — The maximum value for any limits of a

specific equipment variable. This value is set by the

equipment manufacturer and typically coincides with

the maximum value allowed for the monitored variable.

LIMITMIN — The minimum value for any limits of a

specific equipment variable.

This value is set by the

equipment manufacturer and typically coincides with

the minimum value allowed for the monitored variable.

Undefined — When used in reference to variable limits,

it indicates that monitoring/reporting of zone transitions

involving that particular limit are disabled.

4.2.4.3 Description — The limits monitoring capability

provides the host with a minimum of seven

configurable limits or barriers that may be applied to

selected equipment status variables (SV’s) of the types

floating point, integer, and boolean. When one of these

barriers is crossed, a collection event is generated to

alert the host to a change in monitoring zone or state of

the monitored variable. These seven limits may be

combined in a variety of ways to match the needs of the

host system.

An illustration of a combination of five

of the limits to provide one type of variable monitoring

is shown in Figure 4.2.1.

This section describes the

key aspects of limits monitoring. Detailed

implementation examples of limits monitoring are

provided as Application Note A.7.

NOTE 6: While the SEMI E5 standard allows SV’s to be lists,

such variable lists are not allowed under this capability.

4.2.4.3.1 Monitoring Limit Characteristics — A limit

is defined by a set of attributes that include the variable

(VID) to which the limit corresponds, the units of that

variable, the maximum and minimum possible values of

19 Note that while at least seven limits per variable are available from

the equipment, the host need not use all seven.

20 This illustration shows the reading which might be available to the

equipment, not the limit excursions reported to the host. Reporting is

covered later in the section.

the limit (LIMITMAX and LIMITMIN) and the

specific borders of the limit (UPPERDB and

LOWERDB). See Figure 4.2.2. There is a limitation to

the values of UPPERDB and LOWERDB which may

be stated as:

LIMITMAX≥UPPERDB≥LOWERDB≥LIMITMIN

A limit divides the possible range of variable values

into two parts, the upper zone and the lower zone. At

any time, the monitored variable is considered to be in

one and only one of these zones. However, as Figure

4.2.2 shows, these two zones have an area of overlap.

This is called the deadband.

Figure 4.2.1

Limit Combination Illustration: Control

Application

Figure 4.2.2

Elements of One Limit

The deadband is a key concept of limits monitoring,

especially for floating point variables. Its purpose is to

prevent a phenomenon known as chattering — the

repeated changing of zones due to small, rapid

fluctuations in variable value while near the zone

boundary. In practice, the value of a variable must

reach the opposite boundary of the deadband before a

zone transition can occur. Thus, if a variable’s value