Liquid Controls SP4000 - Manual (Page 10)

7
SP4000 Flow Computer
Operation of Serial Communication Port with Printers
The Flow Computer’s RS-232 channel supports a number
of operating modes. One of these modes is intended to
support operation with a printer in metering applications
requiring transaction printing, data logging and/or printing
of calibration and maintenance reports.
For transaction printing, the user defines the items to be
included in the printed document. The user can also select
what initiates the transaction print generated as part of the
setup of the instrument. The transaction document may be
initiated via a front panel key depression.
In data logging, the user defines the items to be included in
each data log as a print list. The user can also select when
or how often he wishes a data log to be made. This is done
during the setup of the instrument as either a time of day or
as a time interval between logging.
The system setup and maintenance report list all the
instrument setup parameters and usage for the current
instrument configuration. In addition, the Audit trail
information is presented as well as a status report listing
any observed malfunctions which have not been corrected.
The user initiates the printing of this report at a designated
point in the menu by pressing the print key on the front
panel.
Operating Serial Communication Port with Modems
The SP4000 offers a number of capabilities that facilitate
its use with modems. The SP4000’s RS232 port can be
connected to a modem in order to implement a remote
metering system that uses either the phone companies
standard phone lines or cellular telephone system. In
addition to remote meter readings, the serial commands
may also be used to examine and/or make setup changes
to the unit, and to check for proper operation or investigate
problems. Several hundred commands are supported. A
compatible industrial modem accessory and interconnecting
cabling is offered in the MPP2400N specifically designed
for use with the SP4000.
The SP4000 and Modem can be used together to create
systems with one or more of the following capabilities:
1.
Poll the SP4000 unit for information from a remote
PC.
2. Call Out from the SP4000 unit to a remote PC on a
scheduled reading time and/or crisis basis
3. Some combination of the above two descriptions where
the unit is polled by one PC and calls into to a different
PC if a problem is detected.
In fact, up to five ST-2 units can share the same modem.
Each SP4000 must have a unique DEVICE ID. This
multidropping of flow computers on a single modem is
popular when there are several flow computers mounted
near each other.
In most applications using modem communications, the
SP4000’s RS232 USAGE is first set equal to MODEM.
Each SP4000 on a shared modem cable is given a unique
serial device address or DEVICE ID. The BAUD RATE is
commonly set to 2400, the PARITY set to NONE, and the
HANSHAKING set to NONE to complete the basic setup.
The remote PC’s communication settings are chosen to
match these.
The level of complexity of the Supetrol-2 to Modem
connection can range from simple to more complex.
In a simple system a remote PC will call into the telephone
number of the modem. The modem will answer the call,
and establish a connection between the SP4000 and the
remote PC. An exchange of information can now occur.
The SP4000 will act as a slave and respond to commands
and requests for information from the remote MASTER
PC. The MASTER PC will end the exchange by handing
up.
However, it is more common that the SP4000 will be used
to control the modem. In these applications the following
communication menu settings would be used:
RS232 USAGE = MODEM
DEVICE ID, BAUD RATE, PARITY, and
HANDSHAKING are set
MODEM CONTROL = YES
DEVICE MASTER = YES (When multidropping
several SP4000's, only one unit will be the DEVICE
MASTER)
MODEM AUTO ANSWER = YES (This instructs the
unit to answer incoming calls)
HANG UP IF INACTIVE = YES (This instructs the
unit to hang up the line if no activities occur within
several minutes).
A more complex form of a remote metering system can be
implemented where the SP4000 will initiate a call to contact
the remote PC at a scheduled time and/or in the event of a
problem that has been detected. In these applications the
SP4000 has additional setup capabilities including:
The SP4000 must have a unique identifier assigned
to it (using the TAG NUMBER)
Call Out Telephone number must be entered in the
CALL OUT NUMBER
The scheduled call out time for the daily reading
must be entered in CALL OUT TIME
A decision must be made whether the unit will be
used to call on error(s) in CALL ON ERROR
The particular error conditions to call out on must be
defined in the ERROR MASK
The NUMBER OF REDIALS to be attempted if line
is busy must be entered in that cell
HANG UP IF INACTIVE= YES will disconnect the
call if remote computer does not respond.