Serial rlc protocol communications, Sending serial commands and data to the meter, Command chart – Red Lion PAX2C User Manual

Page 43: Command string construction, Register identification chart, Command string examples, Sending numeric data

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SERIAL RLC PROTOCOL COMMUNICATIONS

RLC Communications requires the Serial Communications Type Parameter

(tYPE) be set to “rLC”.

SENDING SERIAL COMMANDS AND DATA TO THE METER

When sending commands to the meter, a string containing at least one

command character must be constructed. A command string consists of a

command character, a value identifier, numerical data (if writing data to the

meter) followed by a command terminator character * or $.

Command Chart

COMMAND DESCRIPTION

NOTES

Node (Meter)

Address

Specifier

Address a specific meter. Must be followed by a

two digit node address. Not required when

address = 00.

Transmit Value

(read)

Read a register from the meter. Must be followed

by register ID character

Value Change

(write)

Write to register of the meter. Must be followed by

Reset

Reset a register or output. Must be followed by

Block Print

Request

Initiates a block print output. Registers are defined

in programming.

*, $

Terminator

Signifies end of transmission

Command String Construction

The command string must be constructed in a specific sequence. The meter

does not respond with an error message to invalid commands. The following

procedure details construction of a command string:

1. The first characters consist of the Node Address Specifier (N) followed by a

2 character address number. The address number of the meter is programmable.

If the node address is 0, this command and the node address itself may be

omitted. This is the only command that may be used in conjunction with other

commands.

2. After the optional address specifier, the next character is the command

character.

3. The next character is the Register ID. This identifies the register that the

command affects. The P command does not require a Register ID character.

It prints according to the selections made in print options.

4. If constructing a value change command (writing data), the numeric data is

sent next.

5. All command strings must be terminated with the string termination

characters *, or $. The meter does not begin processing the command string

until this character is received. See Timing Diagram figure for differences

between terminating characters.

Register Identification Chart

VALUE DESCRIPTION

MNEMONIC APPLICABLE COMMANDS/COMMENTS

Signal Input

INP

T, P

Active Setpoint

SET

T, V, P

Setpoint Ramp Rate

RMP

T, V, P

Output Power

PWR

T, V, P (V only in manual mode)

Proportional Band

PBD

T, V, P

Integral Time

INT

T, V, P

Derivative Time

DER

T, V, P

Alarm Status (1-4)

ALR

T, R, P

Alarm Value 1

AL1

T, V, R, P (Reset command resets

Alarm Outputs)

Alarm Value 2

AL2

Alarm Value 3

AL3

Alarm Value 4

AL4

M Control Parameters

CTL

T, V, P

Auto/Manual Register

MMR

T, V

Analog Output Register

AOR

T, V

Digital Output Register

DOR

T, V

Command String Examples:

1. Node address = 17, Write 350 to Alarm 1.

String: N17VI350$

2. Node address = 5, Read Input value.

String: N5TA*

3. Node address = 0, Reset Alarm 4 output.

String: RL*

Sending Numeric Data

Numeric data sent to the controller must be limited to 4 digits (-1999 to

9999). Leading zeros are ignored. Negative numbers must have a minus sign.

The controller ignores any decimal point and conforms the number to the scaled

resolution. (For example: the meter’s scaled decimal point position = 0.0 and 25

is written to a register. The value of the register is now 2.5.
Note: Since the controller does not issue a reply to value change commands,

follow with a transmit value command for readback verification.

REGISTER

ADDRESS

REGISTER NAME

LOW LIMIT

HIGH LIMIT

FACTORY

SETTING

ACCESS

COMMENTS

40051

Active Alarm 3 Band/Dev. Value

-1999

9999