Reading data from an eHZ-IW8E2A5 residential meter

read_ehz.sh

#!/bin/bash
# read and evaluate SML output received from EMH eHZ

# set serial device
INPUT_DEV="/dev/ttyUSB0"

#set $INPUT_DEV to 9600 8N1
stty -F $INPUT_DEV 1:0:8bd:0:3:1c:7f:15:4:5:1:0:11:13:1a:0:12:f:17:16:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0

SML_START_SEQUENCE="1B1B1B1B0101010176"
METER_OUTPUT__START_SEQUENCE=""

while [ "$METER_OUTPUT__START_SEQUENCE" != "$SML_START_SEQUENCE" ]
do
        METER_OUTPUT=`cat $INPUT_DEV 2>/dev/null | xxd -p -u -l 460`
        METER_OUTPUT__START_SEQUENCE=$(echo "${METER_OUTPUT:0:18}")
        if [ $METER_OUTPUT__START_SEQUENCE != $SML_START_SEQUENCE ];
        then
                echo "missed start and trying again..."
                #exit 1 
        fi
done

METER_OUTPUT="${METER_OUTPUT//[[:space:]]/}"
#echo ${METER_OUTPUT:568:8}

let METER_180=0x${METER_OUTPUT:310:10}
VALUE=$(echo "scale=2; $METER_180 / 10000" |bc)
echo "Meter 1.8.0 (from plant):    " $VALUE "kWh"

let METER_180=0x${METER_OUTPUT:358:10}
VALUE=$(echo "scale=2; $METER_180 / 10000" |bc)
echo "Meter 2.8.0 (to plant):      " $VALUE "kWh"

let METER_180=0x${METER_OUTPUT:568:8}
VALUE=$(echo "scale=2; $METER_180 / 10" |bc)
echo "Total effective power (+/-): " $VALUE "W"