RRM 3-14 Timer

EPICS Record Reference Manual

Timer

The timer record is provided as a means for configuring timing outputs. These records will drive an output that may be used to latch data into analog inputs or waveform digitizers.

Parameter Fields

The fields for the timer record fall into the following categories:

• scan parameters
• setup parameters
• write and convert parameters
• operator display parameters
• event generation parameters
• run-time parameters

Scan Parameters

The timer record has the standard fields for specifying under what circumstances it will be processed. In addition, the VAL field is provided in the timer record to force record processing when written to. The other fields are listed in Scan Fields. In addition, Scanning Specification explains how these fields are used. Note that I/O event scanning is only supported for those card types that interrupt.

Field	Summary	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
VAL	Value Field	SHORT	No	0	Yes	Yes	Yes	Yes

Setup Parameters

The timer record has fields needed to initialize a motor. The trigger source (TRSC) field is usually configured to come in from an external signal. This is configured in the record by setting TSRC to external, the only other choice being internal. The pre-trigger state field (PSRC) is the state of the timing channel when it is not fired. The timing channel usually goes high when the timing pulse is present. In such a case the pre-trigger state is low.

Field	Summary	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
TSRC	Clock Source	RECCHOICE	Yes	0	Yes	Yes	No	No
PTST	Pre-Trigger State	RECCHOICE	Yes	0	Yes	Yes	No	Yes

Write and Convert Parameters

The delays and outputs are specified in the time units (TIMU), which has four choices based on seconds: Milliseconds, Microseconds, Nanoseconds, and Picoseconds.

There are delays and pulse widths for five timing pulses per channel. The pulse width for each should be specified in the OPW1-OPW5 fields, in the units chosen in the TIMU field. The delay width for each trigger is specified in the DUT1-DUT5 fields. The delay width is the time in between pulses. These fields are converted to seconds by the run-time code before being used.

The value of the trigger delay field (TRDL) fetched from the trigger origin (TORG) field is added to the delay for each of these five signals. The TORG and TRDL work like the desired output parameters of other output records. TORG can be a channel access or database link, or a constant. If TORG is a constant, TRDL is initialized to the constant value and can be changed at run-time via dbPuts. Using the TORG field one can set up timing chains which are relative to other timing signals. See Address Specification for information on how to specify database links.

The desired output is sent to the address contained in the output link (OUT). The DTYP field must contain the name of a valid device support module. The user can see a list of the device support modules currently supported at the user's local site by using the dbst utility (R3.13).

Field	Summary	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
TORG	Trigger Delay Origin (input link)	INLINK	Yes	0	No	No	N/A	No
TRDL	Trigger Delay	FLOAT	No	0	Yes	Yes	No	No
TIMU	Timer Units	RECCHOICE	Yes	0	Yes	Yes	No	No
DTYP	Device Type	DEVCHOICE	Yes	0	Yes	No	No	No
OUT	Output Link	OUTLINK	Yes	0	No	No	N/A	No
DUT1	Delay Width for trigger 1	FLOAT	Yes	0	Yes	Yes	No	Yes
OPW1	Pulse width for Trigger 1	FLOAT	Yes	0	Yes	Yes	No	Yes
DUT2	Delay Width for Trigger 2	FLOAT	Yes	0	Yes	Yes	No	Yes
OPW2	Pulse Width for Trigger 2	FLOAT	Yes	0	Yes	Yes	No	Yes
DUT3	Delay Width for Trigger 3	FLOAT	Yes	0	Yes	Yes	No	Yes
OPW3	Pulse Width for Trigger 3	FLOAT	Yes	0	Yes	Yes	No	Yes
DUT4	Delay Width for Trigger 4	FLOAT	Yes	0	Yes	Yes	No	Yes
OPW4	Pulse Width for Trigger 4	FLOAT	Yes	0	Yes	Yes	No	Yes
DUT5	Delay Width for Trigger 5	FLOAT	Yes	0	Yes	Yes	No	Yes
OPW5	Pulse Width for Trigger 5	FLOAT	Yes	0	Yes	Yes	No	Yes

Operator Display Parameters

The PDLY field displays the delay from source to input, which is the time is takes for the timing signal to get from its output to the trigger. It is not used by the run-time code, but characterizes the timing signals for the operator's knowledge.

See Fields Common to All Record Types for more on the record name (NAME) and description (DESC) fields.

Field	Summary	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
PDLY	Delay Source to Input	FLOAT	Yes	0	Yes	Yes	No	No
NAME	Record Name	STRING [29]	Yes	0	Yes	No	No	No
DESC	Description	STRING [29]	Yes	Null	Yes	Yes	No	No

Alarm Parameters

The timer record has the alarm parameters common to all record types. Alarm Fields lists other fields related to a alarms that are common to all record types.

Event Generation Parameters

The timing event (TEVT) field is used to generate internal events for processing records on an event. It should be an integer representing an event number.

Field	Summary	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
TEVT	Event Number To Be Posted On Trigger.	SHORT	Yes	0	Yes	Yes	No	Yes

Run-time Parameters

These parameters are used by the run-time code for processing the timing channel. They are not configured using a configuration tool. They represent the current state of the timing channel.

The T1DL-T5DL and T1WD-T5WD fields are where the record stores the user-configured delay widths and pulse widths for the five triggers (DUT1-DUT5 and OPW1-OPW5) after it has converted them to seconds.

The T1TD-T5TD and T1LD-T5LD fields hold the trailing and leading trigger delays for each trigger. These fields are calculated by the record as follows:

TnLD = DUTn + TRDL
TnTD = TnLD + OPWn

where n represents the trigger number.

Field	Summary	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
T1DL	Delay Width for Trigger 1	DOUBLE	No	0	Yes	Yes	No	No
T1WD	Pulse Width for Trigger 1	DOUBLE	No	0	Yes	Yes	Yes	No
T2DL	Delay Width for Trigger 2	DOUBLE	No	0	Yes	Yes	No	No
T2WD	Pulse Width for Trigger 2	DOUBLE	No	0	Yes	Yes	No	No
T3DL	Delay Width for Trigger 3	DOUBLE	No	0	Yes	Yes	No	No
T3WD	Pulse Width for Trigger 3	DOUBLE	No	0	Yes	Yes	No	No
T4DL	Delay Width or Trigger 4	DOUBLE	No	0	Yes	Yes	No	No
T4WD	Pulse Width for Trigger 4	DOUBLE	No	0	Yes	Yes	No	No
T5DL	Delay width for Trigger 5	DOUBLE	No	0	Yes	Yes	No	No
T5WD	Pulse Width for Trigger 5	DOUBLE	No	0	Yes	Yes	No	No
T1TD	Trigger 1 Trailing Delay	FLOAT	No	0	Yes	Yes	Yes	No
T1LD	Trigger 1 Leading Delay	FLOAT	No	0	Yes	Yes	Yes	No
T2TD	Trigger 2 Trailing Delay	FLOAT	No	0	Yes	Yes	No	No
T2LD	Trigger 2 Leading Delay	FLOAT	No	0	Yes	Yes	No	No
T3TD	Trigger 3 Trailing Delay	FLOAT	No	0	Yes	Yes	No	No
T3LD	Trigger 3 Leading Delay	FLOAT	No	0	Yes	Yes	No	No
T4TD	Trigger 4 Trailing Delay	FLOAT	No	0	Yes	Yes	No	No
T4LD	Trigger 4 Leading Delay	FLOAT	No	0	Yes	Yes	No	No
T5TD	Trigger 5 Trailing Delay	FLOAT	No	0	Yes	Yes	No	No
T5LD	Trigger 5 Leading Delay	FLOAT	No	0	Yes	Yes	No	No
TDIS	Timing Pulse Disable	SHORT	No	0	Yes	Yes	No	Yes
MAIN	Maintain on Reboot	GBLCHOICE	Yes	1	Yes	Yes	No	Yes
RDT1	Reboot Delay of 1	FLOAT	No	0	Yes	Yes	No	No
RDW1	Reboot Width of 1	FLOAT	No	0	Yes	Yes	No	No

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EPICS Record Reference Manual - 19 MAY 1998