From eb5ceb3f226d6f2b0e6514f4b9c93970df8cc4ef Mon Sep 17 00:00:00 2001
From: decadenza <pasquale.lafiosca@proactive-analytics.com>
Date: Thu, 2 Nov 2023 11:33:25 +0000
Subject: [PATCH 1/2] Wait for correct response id

---
 client.go | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/client.go b/client.go
index 2535b72..1e70206 100644
--- a/client.go
+++ b/client.go
@@ -7,6 +7,7 @@ package modbus
 import (
 	"encoding/binary"
 	"fmt"
+	"time"
 )
 
 // logger is the interface to the required logging functions
@@ -487,12 +488,24 @@ func (mb *client) send(request *ProtocolDataUnit) (response *ProtocolDataUnit, e
 	if err != nil {
 		return
 	}
-	aduResponse, err := mb.transporter.Send(aduRequest)
-	if err != nil {
-		return
-	}
-	if err = mb.packager.Verify(aduRequest, aduResponse); err != nil {
-		return
+
+	// Wait for correct response ID before throwing error.
+	var aduResponse []byte
+	maxTime := time.Now().Add(tcpTimeout)
+	for {
+		aduResponse, err = mb.transporter.Send(aduRequest)
+		if err != nil {
+			return
+		}
+		err = mb.packager.Verify(aduRequest, aduResponse)
+
+		if err == nil {
+			break
+		}
+		if time.Now().After(maxTime) {
+			return
+		}
+		// Else try again until timeout.
 	}
 	response, err = mb.packager.Decode(aduResponse)
 	if err != nil {

From c44b32a3860bc201ed1f373ae3cde0bf17273c58 Mon Sep 17 00:00:00 2001
From: decadenza <pasquale.lafiosca@proactive-analytics.com>
Date: Fri, 3 Nov 2023 12:23:50 +0000
Subject: [PATCH 2/2] Added error return value

---
 client.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/client.go b/client.go
index 1e70206..8c4f7cd 100644
--- a/client.go
+++ b/client.go
@@ -503,6 +503,7 @@ func (mb *client) send(request *ProtocolDataUnit) (response *ProtocolDataUnit, e
 			break
 		}
 		if time.Now().After(maxTime) {
+			err = fmt.Errorf("modbus: response timeout")
 			return
 		}
 		// Else try again until timeout.