From 692931e65fece7199465dbbb39fb5b95acc09415 Mon Sep 17 00:00:00 2001
From: Ismo Leszczynski <ismo.leszczynski@prosysopc.com>
Date: Wed, 9 Apr 2025 14:29:40 +0300
Subject: [PATCH 1/2] Update ModbusOptimizer.java

Fix Discrete Input handling when processing response
---
 .../plc4x/java/modbus/base/optimizer/ModbusOptimizer.java  | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/plc4j/drivers/modbus/src/main/java/org/apache/plc4x/java/modbus/base/optimizer/ModbusOptimizer.java b/plc4j/drivers/modbus/src/main/java/org/apache/plc4x/java/modbus/base/optimizer/ModbusOptimizer.java
index db838c6a0b..c604eed96e 100644
--- a/plc4j/drivers/modbus/src/main/java/org/apache/plc4x/java/modbus/base/optimizer/ModbusOptimizer.java
+++ b/plc4j/drivers/modbus/src/main/java/org/apache/plc4x/java/modbus/base/optimizer/ModbusOptimizer.java
@@ -192,7 +192,7 @@ protected PlcReadResponse processReadResponses(PlcReadRequest readRequest, Map<P
                 }
                 // Go through all responses till we find one where that contains the current tag's data.
                 for (Response response : responses.get(tagType)) {
-                    if(modbusTag instanceof ModbusTagCoil) {
+                    if((modbusTag instanceof ModbusTagCoil) || (modbusTag instanceof ModbusTagDiscreteInput)) {
                         if(response.matchesCoil(modbusTag)) {
                             // If this response was invalid, return all associated addresses as equally invalid.
                             // TODO: Possibly it would be worth doing a single item request for each of these
@@ -204,12 +204,11 @@ protected PlcReadResponse processReadResponses(PlcReadRequest readRequest, Map<P
                                 break;
                             }
 
-                            // Coils are read completely different from registers.
-                            ModbusTagCoil coilTag = (ModbusTagCoil) modbusTag;
+                            // Coils and Discrete Inputs are read completely different from registers.
 
                             // Calculate the byte that contains the response for this Coil
                             byte[] responseData = response.getResponseData();
-                            int bitPosition = coilTag.getAddress() - response.startingAddress;
+                            int bitPosition = modbusTag.getAddress() - response.startingAddress;
                             int bytePosition = bitPosition / 8;
                             int bitPositionInByte = bitPosition % 8;
                             boolean isBitSet = (responseData[bytePosition] & (1 << bitPositionInByte)) != 0;

From 0909be4a7284d890e489e20dbadac272dfb9d8a5 Mon Sep 17 00:00:00 2001
From: Ismo Leszczynski <ismo.leszczynski@prosysopc.com>
Date: Wed, 16 Apr 2025 12:54:28 +0300
Subject: [PATCH 2/2] Update ModbusOptimizer.java

Fixed endianness resolution to check modbusTag overrides
---
 .../plc4x/java/modbus/base/optimizer/ModbusOptimizer.java   | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/plc4j/drivers/modbus/src/main/java/org/apache/plc4x/java/modbus/base/optimizer/ModbusOptimizer.java b/plc4j/drivers/modbus/src/main/java/org/apache/plc4x/java/modbus/base/optimizer/ModbusOptimizer.java
index c604eed96e..0bde206c48 100644
--- a/plc4j/drivers/modbus/src/main/java/org/apache/plc4x/java/modbus/base/optimizer/ModbusOptimizer.java
+++ b/plc4j/drivers/modbus/src/main/java/org/apache/plc4x/java/modbus/base/optimizer/ModbusOptimizer.java
@@ -228,12 +228,14 @@ else if (response.matchesRegister(modbusTag)) {
                             break;
                         }
 
+                        var byteOrder = modbusTag.getByteOrder() != null ? modbusTag.getByteOrder() : modbusContext.getByteOrder();
+
                         byte[] responseData = response.getResponseDataForTag(modbusTag);
-                        ReadBuffer readBuffer = getReadBuffer(responseData, modbusContext.getByteOrder());
+                        ReadBuffer readBuffer = getReadBuffer(responseData, byteOrder);
                         try {
                             PlcValue plcValue = DataItem.staticParse(readBuffer, modbusTag.getDataType(),
                                 modbusTag.getNumberOfElements(),
-                                modbusContext.getByteOrder() == ModbusByteOrder.BIG_ENDIAN);
+                                byteOrder == ModbusByteOrder.BIG_ENDIAN);
                             values.put(tagName, new DefaultPlcResponseItem<>(PlcResponseCode.OK, plcValue));
                         } catch (ParseException e) {
                             values.put(tagName, new DefaultPlcResponseItem<>(PlcResponseCode.INTERNAL_ERROR, null));