#!/bin/bash
 
set -e
set -u
 
usage() {
cat <<EOF
$0 [options] register ...
        -t|--tty
        -b|--baudrate
        -p|--parity
        -s|--stopbits
        -a|--addr
EOF
}
 
TEMP="$(getopt -n installremote \
        -l tty:,baudrate:,parity:,stopbits:,addr: -- \
        +t:b:p:s:a: "$@")"
eval set -- "${TEMP}"
 
MBRTU="mbrtu"
TTY=""
BAUDRATE=""
PARITY=""
STOPBITS=""
ADDR=""
 
while test "$1" != "--"; do
        case $1 in
                -t|--tty)
                        shift
                        TTY="$1"
                        ;;
                -b|--baudrate)
                        shift
                        BAUDRATE="$1"
                        ;;
                -p|--parity)
                        shift
                        PARITY="$1"
                        ;;
                -s|--stopbits)
                        shift
                        STOPBITS="$1"
                        ;;
                -a|--addr)
                        shift
                        ADDR="$1"
                        ;;
        esac
        shift
done
shift
 
checkparameter() {
        PARMNAME="${1:-}"
        CONTENT="${2:-}"
        if [ -z "${CONTENT}" ]; then
                printf "%s must not be empty\\n" "${PARMNAME}"
                exit 1
        fi
}
 
checkparameter tty "${TTY}"
checkparameter baudrate "${BAUDRATE}"
checkparameter parity "${PARITY}"
checkparameter stopbits "${STOPBITS}"
checkparameter addr "${ADDR}"
 
for reg in "$@"; do
        NOW="$(date +%s)"
        METER="$($MBRTU -d"${TTY}" -b"${BAUDRATE}" -p"${PARITY}" -s"${STOPBITS}" -Q -P -a"${ADDR}" -f3 -tF32_dcba -n2 -r"${reg}" | cut -d\  -f3)"
 
        if [ -z "${METER}" ]; then
                printf >&2 "no data received on modbus\\n"
        else
                printf "%d: %s = %f\\n" "${NOW}" "${reg}" "${METER:-0}"
        fi
done
 
# end of file