Rs-485 serial commands – Max Machinery 120 FLOW RATE & TOTAL INDICATOR User Manual

Page 21

Page 21

RS-485 SERIAL COMMANDS

Classifications

All serial commands fall into one of five classifications. These classifications are:

1. Control Commands

2. Query Run Data

3. Load Run Data

4. Query Program Data

5. Load Program Data

The Max 120 Indicator has two modes of operation: run mode and program mode. The
indicator will respond to specific commands only if the command is valid for the mode of
operation the unit is in when the command is received. Command validity is addressed in the
following section and all specific commands are described in detail in the following tables.

Using The Control Commands

There are three control commands. Two of them, Enter Program Mode and Exit Program
Mode are used to change the indicator’s mode of operation. The following flow chart
illustrates the validity and function of each control command and the validity of the other
four command classifications in each mode of operation. Note that the indicator goes into the
run mode when it powers up.

The third control command, Reset, does not change the indicator’s mode of operation, but
merely performs a reset and/or unlatch function while leaving the indicator in the run mode.
The Reset control command is suffixed by one digit (a) which allows for secondary functions
to occur along with the Reset function. All secondary functions are listed in the following
control command table.

RS-485 SERIAL COMMANDS

Valid Commands

Reset (RSTa)

Enter Prog. Mode

(EPM)

query run data

load run data

Valid Commands
Exit Prog. Mode

(PEX)

query prog. data

load prog. data

QST

Power Up

Run Program