HDLC Address Calculation for RS485 Multidrop
User example : VC1100 Meter ? Addressing Guidance
1. Introduction
When configuring multidrop communication over RS485 for the VC1100 meter, each meter must have a unique HDLC address to ensure proper communication on the bus.
This document explains:
How the HDLC address is derived
Whether the address is calculated or configured
Step-by-step calculation method
2. Understanding the Addressing Structure
2.1 Upper HDLC Address
The Upper HDLC address is fixed as: 0x00 0x02
2.2 Lower HDLC Address
The Lower HDLC address is derived from the meter?s serial number.
The calculation is based on:
The last 5 decimal digits of the serial number
A modulus operation using 15000
This calculated value becomes the HDLC address corresponding to the serial number.
Please note: If the last five decimal digits are less than 17, add 15000 to that value. The result will be the lower HDLC address.
Example: Serial number ending in 00011 → 11 < 17 → 11 + 15000 = 15011
3. Address Calculation Procedure
Follow the steps below to calculate the HDLC address:
Step 1: Extract the Last 5 Digits
Take the last five (5) decimal digits of the meter?s serial number.
Example format:
Meter Serial Number: 026129141324
Last 5 Digits: 41324
Step 2 ? Modulus 15000:
Perform the following calculation:
Remainder = (Last 5 Digits) % 15000
Where % represents the modulus (remainder after division).
Example :
41324 % 15000 = 11324 (Which is the remainder)
Please view Image on the folder as references.
Tags: multidrop idveryco