From 58177f60c124100fff759731d7f314c44d81db4e Mon Sep 17 00:00:00 2001
From: andig <cpuidle@gmx.de>
Date: Mon, 3 Aug 2020 07:23:54 +0200
Subject: [PATCH] Silence NaN reading errors by treating NaN as zero (#261)

---
 go.mod             | 2 +-
 go.sum             | 2 ++
 meter/modbus.go    | 8 ++++++++
 provider/modbus.go | 6 ++++++
 4 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/go.mod b/go.mod
index 75a007f20..f4e0f2296 100644
--- a/go.mod
+++ b/go.mod
@@ -33,7 +33,7 @@ require (
 	github.com/spf13/jwalterweatherman v1.1.0
 	github.com/spf13/viper v1.7.0
 	github.com/tcnksm/go-latest v0.0.0-20170313132115-e3007ae9052e
-	github.com/volkszaehler/mbmd v0.0.0-20200717102329-c4d965bd1eac
+	github.com/volkszaehler/mbmd v0.0.0-20200802164800-51eb643c23c6
 	github.com/yuin/goldmark v1.1.32
 	golang.org/x/net v0.0.0-20200707034311-ab3426394381
 	golang.org/x/tools v0.0.0-20200717024301-6ddee64345a6
diff --git a/go.sum b/go.sum
index a4d0fd840..68a6e483f 100644
--- a/go.sum
+++ b/go.sum
@@ -348,6 +348,8 @@ github.com/valyala/fasttemplate v1.0.1/go.mod h1:UQGH1tvbgY+Nz5t2n7tXsz52dQxojPU
 github.com/valyala/fasttemplate v1.1.0/go.mod h1:UQGH1tvbgY+Nz5t2n7tXsz52dQxojPUpymEIMZ47gx8=
 github.com/volkszaehler/mbmd v0.0.0-20200717102329-c4d965bd1eac h1:LnvR04M0HuzjTbRzMpE5jRHcNu46CvG1FOtMcZAX8C4=
 github.com/volkszaehler/mbmd v0.0.0-20200717102329-c4d965bd1eac/go.mod h1:sldLyJCKVO9GQkit55U5WPNr9U4KmUn1SCdqFN9Gjb4=
+github.com/volkszaehler/mbmd v0.0.0-20200802164800-51eb643c23c6 h1:cs1lwT44CyqStjTmYe0vGDhQHEaBpYZh0dgXPQLeEpY=
+github.com/volkszaehler/mbmd v0.0.0-20200802164800-51eb643c23c6/go.mod h1:sldLyJCKVO9GQkit55U5WPNr9U4KmUn1SCdqFN9Gjb4=
 github.com/xiang90/probing v0.0.0-20190116061207-43a291ad63a2/go.mod h1:UETIi67q53MR2AWcXfiuqkDkRtnGDLqkBTpCHuJHxtU=
 github.com/xordataexchange/crypt v0.0.3-0.20170626215501-b2862e3d0a77/go.mod h1:aYKd//L2LvnjZzWKhF00oedf4jCCReLcmhLdhm1A27Q=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
diff --git a/meter/modbus.go b/meter/modbus.go
index f63c0620b..9071530d6 100644
--- a/meter/modbus.go
+++ b/meter/modbus.go
@@ -1,6 +1,8 @@
 package meter
 
 import (
+	"errors"
+
 	"github.com/andig/evcc/api"
 	"github.com/andig/evcc/util"
 	"github.com/andig/evcc/util/modbus"
@@ -113,6 +115,12 @@ func (m *Modbus) floatGetter(op modbus.Operation) (float64, error) {
 		}
 	}
 
+	// silence NaN reading errors by assuming zero
+	if err != nil && errors.Is(err, meters.ErrNaN) {
+		res.Value = 0
+		err = nil
+	}
+
 	if err != nil {
 		m.conn.Close() // close connection in case of modbus error
 	} else {
diff --git a/provider/modbus.go b/provider/modbus.go
index 5c029d009..54058671b 100644
--- a/provider/modbus.go
+++ b/provider/modbus.go
@@ -156,6 +156,12 @@ func (m *Modbus) FloatGetter() (float64, error) {
 		}
 	}
 
+	// silence NaN reading errors by assuming zero
+	if err != nil && errors.Is(err, meters.ErrNaN) {
+		res.Value = 0
+		err = nil
+	}
+
 	if err != nil {
 		m.conn.Close() // close connection in case of modbus error
 	} else {