Red-lion PAX2D User Manual download pdf (Page 27)

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 $. The <CR> is also

available as a terminator when Counter C is in the SLAVE mode.

Command Chart

COMMAND DESCRIPTION NOTES

N Node (Meter)

Address

Specifier

Address a specific meter. Must be followed by a

two digit node address. Not required when

address = 00.

T Transmit Value

(read)

Read a register from the meter. Must be followed

by register ID character

V Value Change

(write)

Write to register of the meter. Must be followed by

R Reset Reset a register or output. Must be followed by

P Block Print

Request

Initiates a block print output. Registers are defined

in programming.

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

1 or 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. For node address 1 through 9, a leading zero character

is not required. (The only exception is a numeric transmission when Counter

C is set for slave mode.) 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 when Counter C is set for slave mode <CR>. The meter

does not begin processing the command string until this character is received.

See Timing Diagram figure for differences between terminating characters.

Sending Numeric Data

Numeric data sent to the meter must be limited to the digit range shown under

transmit details in the Register Identification Chart. Leading zeros are ignored.

Negative numbers must have a minus sign. The meter 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 meter does not issue a reply to value change commands, follow

with a transmit value command for readback verification.

VALUE

DESCRIPTION

MNEMONIC COMMAND TRANSMIT DETAILS

A Count A CTA T, V, R 9 positive, 8 ½ negative

B Count B CTB T, V, R 9 positive, 8 ½ negative

C Count C CTC T, V, R 9 positive, 8 ½ negative

D Rate A RTA T 6 digit, positive only

E Rate B RTB T 6 digit, positive only

F Rate C RTC T 6 positive, 5 ½ negative

G Max (Hi) Value MAX T, V, R 6 positive, 5 ½ negative

H Min (Lo) Value MIN T, V, R 6 positive, 5 ½ negative

I Scale Factor A SFA T, V 6 digit, positive only

J Scale Factor B SFB T, V 6 digit, positive only

K Counter Load A CLA T, V 6 positive, 5 ½ negative

L Counter Load B CLB T, V 6 positive, 5 ½ negative

M Setpoint 1 SP1 T, V, R 6 positive, 5 ½ negative

O Setpoint 2 SP2 T, V, R 6 positive, 5 ½ negative

Q Setpoint 3 SP3 T, V, R 6 positive, 5 ½ negative

S Setpoint 4 SP4 T, V, R 6 positive, 5 ½ negative

Auto/Manual

MMR T, V 0 – auto, 1 - manual

Analog Output

AOR T, V 0 – 4095 normalized

X Setpoint Register SOR T, V 0 – not active, 1 – active

Command String Examples:

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

String: N17VM350$

2. Node address = 5, Read Count A value.

String: N5TA*

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

String: RS*

RECEIVING DATA FROM THE METER

Data is transmitted by the meter in response to either a transmit command (T),

a print block command (P) or User Function print request. The response from

the meter is either a full field transmission or an abbreviated transmission. The

meter response mode is selected in Serial Port Parameters (Abrv).

Full Field Transmission (Address, Mnemonic, Numeric data)

Byte Description

1, 2 2 byte Node Address field [00-99]

3 <SP> (Space)

4-6 3 byte Register Mnemonic field

7-18 12 byte data field, 10 bytes for number, one byte for sign, one byte for

decimal point

19 <CR> carriage return

20 <LF> line feed

21 <SP>* (Space)

22 <CR>* carriage return

23 <LF>* line feed

* These characters only appear in the last line of a block print.

The first two characters transmitted are the node address, unless the node

address assigned = 0, in which case spaces are substituted. A space follows the

node address field. The next three characters are the register mnemonic.

The numeric data is transmitted next. The numeric field is 12 characters long

(to accommodate the 10 digit totalizer), with the decimal point position floating

within the data field. Negative values have a leading minus sign. The data field

is right justified with leading spaces.

The end of the response string is terminated with a carriage return <CR> and

<LF>. When block print is finished, an extra <SP><CR> <LF> is used to

provide separation between the blocks.

SERIAL RLC PROTOCOL COMMUNICATIONS

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Red-lion PAX2D User Manual Page 27

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