KEP ES749 - Page 10

ES749 Flow Computer
6
Operation of Steam Trap Monitor
In applications on Saturated Steam, the otherwise unused
Compensation Input may be connected to a steam trap monitor
that offers the following compatible output signal levels:
4mA = trap cold
12 mA = trap warm and open (blowing)
20 mA = trap warm and closed
In normal operation a steam trap is warm and periodically opens
and closes in response to the accumulation of condensate. A
cold trap is indication that it is not purging the condensate, a
trap that is constantly blowing is an indication that it is stuck
open. To avoid a false alarm, the ES749 permits the user to
program a delay, or time period, which should be considered
normal for the trap to be either cold, or open. An alarm will
only be activated if the trap is detected as continuously being
in the abnormal states for a time period greater than this TRAP
ERROR DELAY time.
The user selects to use the Compensation Input for Trap
Monitoring by selecting “4-20mA TRAP STATUS as the INPUT
SIGNAL for OTHER INPUT1.
The user can program the ERROR DELAY time in HH:MM
format into both the TRAP ERROR DELAY (cold trap error)
menu and the TRAP BLOWING DELAY (trap stuck open)
menu.
The ES749 will warn the operator of a TRAP ERROR
when an abnormal condition is detected. The error can be
acknowledged by pressing the ENTER key. However, the
problem may reassert itself if there is a continued problem
with the steam trap.
In addition, the event is noted in the ERROR LOG.
It is also possible for the user to program a trap malfunction
as one of the conditions worthy of a CALL OUT of a problem
by selecting this error in the ERROR MASK.
The Data-Logging option of the ES749 can also be used to log
the performance of the trap by storing the % of time the trap
has been cold, and/or blowing open during the datalog interval.
Datalogging Option
The Datalogging Option for the ES749 permits the user to
automatically store sets of data items as a record on a periodic
basis. A datalog record may be stored as the result of either a
PRINT key depression, or an INTERVAL, or a TIME OF DAY
request for a datalog.
The user denes the list of items to be included in each datalog
by selecting these in the PRINT LIST menu located within the
COMMUNICATIONS SUBMENU.
The user selects what will trigger a datalog record being stored
in the PRINT INITIATE menu. The choices are PRINT KEY,
INTERVAL, and TIME OF DAY.
The user can select the datalog store interval in a HH:MM
format in the PRINT INTERVAL menu.
The user can also select the store time of day in a 24 hr HH:
MM format in the PRINT TIME menu.
The user can also dene whether he just wants the data stored
into the datalogger, or if he wants the data both stored in the
datalogger and sent out over the RS232 port in the DATALOG
ONLY menu.
The user can dene the format he wishes the data to be output
in using the DATALOG FORMAT menu. Choices are PRINTER
and DATABASE. PRINTER format will output the data records
in a form suitable to dump to a printer. DATABASE format will
output the values in a CSV, or Comma Separated Variable with
Carriage return delimiting of each record.
A number of serial commands are also included to access and
manipulate information stored with in the datalogger. Among
these RS232 command capabilities are the following actions:
Clear Data Logger
Send all Data in Datalogger
Send Only New Data since Datalogger was last Read
Send Data for the date included in the request
Send the column heading text for the CSV data elds
Send the column units of measure text for the CSV data
elds
Store one new record into datalogger now
Read Number of New Records in the datalogger
Read number of records currently in the datalogger
Read the maximum number of records capacity of the
datalogger
Move Pointer Back N records
Dump Record at Pointer
Dump records newer than pointer
Dump data from N records back
The datalogger option is used in conjunction with the RS-232
port in remote metering applications.
The technical details associated with the serial commands
are listed in Universal Serial Protocol Manual available upon
request.
RS-232 Serial Port
The Flow Computer has a general purpose RS-232 Port
which may be used for any one of the following purposes:
Transaction Printing
Data Logging
Remote Metering by Modem
Computer Communication Link
Conguration by Computer
Print System Setup
Print Calibration/Malfunction History
Instrument Setup by PC’s over Serial Port
A Diskette program is provided with the Flow Computer that
enables the user to rapidly congure the Flow Computer
using an Personnel Computer. Included on the diskette are
common instrument applications which may be used as a
starting point for your application. This permits the user to
have an excellent starting point and helps speed the user
through the instrument setup.