Liquid Controls SP3850 - Manual (Page 24)

SP3850 Flow Computer
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5.4.6 RS-232 Serial Port Operation in Batcher mode
The RS-232 serial port can be used for programming (using the Setup Disk)
or for communicating to printers and computers in the Operating Mode (Run
Mode).
PC Communications:
The Setup Disk also allows the user to query the unit for operating status such
as Flow Rate, Flow Total, Temperature, Pressure, Density, Presets, etc.
Operation of RS-232 Serial Port with Printers:
Transaction Printing
For transaction printing, the user defines the items to be included in the
printed document (see section 6.4.22 SET DATALOG/PRINT, Select_list).
The transaction document can be initiated by pressing the PRINT key, by a
remote contact closure or print at end of batch.
Data Logging
In data logging, the user defines the items to be included in each data log (see
section 6.4.22 SET DATALOG/PRINT, Select_list). The user can also select
when (time of day) or how often (print interval) the data log is to be made (see
section see section 6.4.21 SET DATALOG/PRINT, Configure).
System Setup and Maintenance Report
The system setup and maintenance report lists all of the instrument setup
parameters and usage for the current instrument configuration. The audit trail
information and a status report is also printed. This report is initiated in the
Test menu (see section 8.2.3 PRINT SYSTEM SETUP).
5.4.7 RS-485 Serial Port (optional)
RS-485 Port Description:
The optional RS-485 card utilizes Modbus RTU protocol to access
a variety of process parameters and totalizers. Batches/Relays
can be controlled remotely via Modbus. In addition, action routines
can be executed. For further information, contact factory and
request RS-485 Protocol manual.
Operation of Serial Communication Port with PC
The flow computer's RS-485 channel supports a number of
Modbus RTU commands. Modbus RTU drivers are available for
a variety of Man Machine Interface software for IBM compatible
PC's.
The user reads and writes information from/to the RS-485 using
the Modbus RTU commands. The SP3850 then responds to
these information and command requests.
Process variables and totalizers are read in register pairs in
floating point format. Time and date are read as a series of
integer register values. Alarms are individually read as coils.
Action routines such as Start, Stop, Reset are initiated by writing
to coils.
RS-232 Serial Port
(Batch mode)
RS-485 Serial Port
(Batch mode)