Arch Meter Corporation PS1000 Evaluation Board User Guide V1.0
PS1000Rev. 1.1 Mar.2006 8/ 22 www.archmeter.com
kWh Pulse Output
kWh Pulse Output time calculated by Timer0 , and pulse outputted at p1.0
Calculation for kWh pulse output time
Let meter constant as Kh (wh/pulse) ,
Current usage as a watt
then time interval of two pulse outputs will be
a
Kh
t6060 ××
=sec
Ex : meter constant is 20 wh/pulse , Current conditions are 110V , 5A , PF=0.8
the time interval between two pulse can be found as
6363.163
8.05110
606020 =
×× ××
=tsec
Communication
Potocol : Modbus
Transmission Modes : RTU mode
The format for each byte in RTU mode is:
Coding System: 8–bit binary, hexadecimal 0–9, A–F
Two hexadecimal characters contained in each
8–bit field of the message
Bits per Byte: 1 start bit
8 data bits, least significant bit sent first
2 stop bits
Error Check Field: Cyclical Redundancy Check (CRC)
Function Codes
The function code part of a Modbus message defines the action to be taken by the
slave.
The Integral products support the following function codes:
Code MODBUS_ name Description
03 Read Holding Registers Read the contents of read/write location
04 Read Input Registers Read the contents of read only location
16 Pre-set Multiple Registers Set the contents of read/write location
