Instructions

UM-0085-B09 DT80 Range User Manual Page 27
RG
Define Measurement Schedules
A schedule defines when a set of channels should be measured. It consists of a list of channel definitions preceded by a
scan trigger specification. See Schedules (P48).
As a general rule when creating schedules, don’t instruct the DT80 to read channels more frequently than is really
necessary. For example, temperatures generally change slowly so rapid reading does not provide extra useful
information.
Up to eleven different schedules can be declared (A to K), each with a different trigger based on a time interval or a
digital input event. The schedule’s trigger can be changed at any time, either manually or under program control.
A list of channels without a trigger specification can be entered at any time. These are scanned immediately, without
affecting other schedules that may be operating. For more information, see Immediate Report Schedules (P56).
Important Whilst a schedule’s trigger can be changed at any time, its channel list cannot be altered without re-entering
all schedules. In fact, all schedules must be entered at the same time, either all on one line or between BEGIN and END
keywords (see Working with Schedules (P58)).
Jobs
A DT80 job is a logical "hold-all" for a group of schedule definitions and other commands. The command BEGIN signifies
the start of a job, and the command END signifies the end of the job. Once a job has been fully entered, the DT80 will
activate all schedules defined therein.
The DT80 can store more than one job (each with its own separate logged data and alarms), but only one can be the
current/active job. See Jobs (P61) for more details.
Scaling and Calculations
The DT80 can scale the channel input data to engineering units by applying intrinsic functions, spans or polynomials.
Arithmetic expressions provide cross-channel and other calculations. Various statistical functions, including averaging
and histogram channel options, can be applied. See Scaling (P65).
Reducing Data
In many instances the volume of the data recorded can be reduced by taking averages, maximums, minimums, standard
deviations, histograms or integrals. See Statistical Channel Options (P76).
Alarms and Conditional Execution
The DT80’s alarm facility is flexible and powerful. Alarms are used to warn of certain conditions (e.g. setpoint exceeded)
and to control the DT80’s operation. Alarms can
• control DT80 digital state outputs
• initiate execution of DT80 commands
• trigger the sending of messages to the host computer.
• set variables
Executing DT80 commands from an alarm can be particularly useful in modifying the DT80’s programming in response to
changes in input(s). See Alarms (P82).
Data Logging
The DT80 stores measurements in its internal data store or in a removable USB memory device. Logging begins only
after you issue the
LOGON command. Time and date stamping is automatic.
By default, the DT80 overwrites the oldest data with new data once the memory is full. If you prefer to have the logger
stop logging once the memory is full then you need to set the no-overwrite schedule option
(NOV)(P49).
For more details see Logging and Retrieving Data (P94).
 Selective Logging
To selectively log channels and schedules:
• For channels, use the
NL (no log) channel option
• For schedules, use the
LOGONx & LOGOFFx commands
See Enabling and Disabling Data Logging (P94).