Adjusted mutex lock and delay for modbus

lib/TEMP/R4DCB08_Driver.cpp

@@ -5,12 +5,24 @@ namespace drivers
     R4DCB08::R4DCB08(drivers::MODBUS &bus, const uint8_t address) : m_address(address), m_bus(bus), m_sensors(0)
     {
         m_sensors = getNum();
+        m_lastRequest = millis();
     }
 
     R4DCB08::~R4DCB08()
     {
     }
 
+    void R4DCB08::delayRequest()
+    {
+        auto now = millis();
+        if ((now - m_lastRequest) < c_minDelay)
+        { // minimum m_lastRequest between requests
+            LOG_DEBUG("R4DCB08 delay request", (now-m_lastRequest));
+            delay(now - m_lastRequest);
+        }
+        m_lastRequest = millis();
+    }
+
     const float R4DCB08::getTemp(const uint8_t ch)
     {
         uint8_t retries(0);
@@ -20,16 +32,16 @@ namespace drivers
             LOG_ERROR("Invalid Temperature Channel number", ch);
             return MAXFLOAT;
         }
-        auto lock = m_bus.getLock();
-        while (retries++ < maxRetries)
+        std::lock_guard<std::mutex> lock(m_bus.getMutex());
+        while (retries++ < c_maxRetries)
         {
+            delayRequest();
             if (m_bus.readHoldingRegisters(m_address, REG_TEMP + ch, 1, rawT) && !rawT.empty())
             {
                 return rawT.front() / 10.0f;
             }
             LOG_ERROR("Failed to Read Temperature, device", m_address, "channel", ch);
             rawT.clear();
-            delay(50);
         }
         return MAXFLOAT;
     }
@@ -39,9 +51,10 @@ namespace drivers
         uint8_t retries(0);
         std::vector<uint16_t> rawT;
         std::vector<float> out;
-        auto lock = m_bus.getLock();
-        while (retries++ < maxRetries)
+        std::lock_guard<std::mutex> lock(m_bus.getMutex());
+        while (retries++ < c_maxRetries)
         {
+            delayRequest();
             if (m_bus.readHoldingRegisters(m_address, REG_TEMP, getNum(), rawT) && !rawT.empty())
             {
                 out.reserve(rawT.size());
@@ -53,7 +66,6 @@ namespace drivers
             }
             LOG_ERROR("Failed to Read All Temperature, device", m_address);
             rawT.clear();
-            delay(50);
         }
         out.clear();
         return out;
@@ -64,20 +76,18 @@ namespace drivers
         uint8_t retries(0);
         uint8_t channel(0);
         corr.resize(getNum()); // max number of temperature correction values is equal to number of sensors
-
-        auto lock = m_bus.getLock();
+        std::lock_guard<std::mutex> lock(m_bus.getMutex());
         for (auto v : corr)
         {
-            while (retries++ < maxRetries)
+            while (retries++ < c_maxRetries)
             {
+                delayRequest();
                 if (m_bus.writeRegister(m_address, REG_TEMPCORR + channel, v * 10)) // convert to decimal degreees to register value
                 {
                     channel++;
-                    delay(50);
                     break;
                 }
                 LOG_ERROR("Failed to Set Temperature Correction, device", m_address);
-                delay(50);
             }
         }
     }
@@ -89,9 +99,10 @@ namespace drivers
         std::vector<float> out;
         rawV.reserve(getNum());
 
-        while (retries++ < maxRetries)
+        std::lock_guard<std::mutex> lock(m_bus.getMutex());
+        while (retries++ < c_maxRetries)
         {
-            auto lock = m_bus.getLock();
+            delayRequest();
             if (m_bus.readHoldingRegisters(m_address, REG_TEMPCORR, getNum(), rawV))
             {
                 out.reserve(rawV.size());
@@ -103,7 +114,6 @@ namespace drivers
             }
             LOG_ERROR("Failed to Get Temperature Correction, device", m_address);
             rawV.clear();
-            delay(50);
         }
         out.clear();
         return out;
@@ -116,9 +126,10 @@ namespace drivers
         uint8_t retries(0);
         uint8_t sensors(0);
         std::vector<uint16_t> rawT;
-        while (retries++ < maxRetries)
+        std::lock_guard<std::mutex> lock(m_bus.getMutex());
+        while (retries++ < c_maxRetries)
         {
-            auto lock = m_bus.getLock();
+            delayRequest();
             if (m_bus.readHoldingRegisters(m_address, REG_TEMP, T_MAX, rawT))
             {
                 for (auto v : rawT)
@@ -130,7 +141,6 @@ namespace drivers
                 return m_sensors;
             }
             LOG_ERROR("Failed to Get Sensor Number, device", m_address);
-            delay(50);
         }
         LOG_ERROR("No Temperature Sensors Detected, device", m_address);
         return 0;

lib/TEMP/R4DCB08_Driver.h

@@ -25,7 +25,9 @@ namespace drivers
             T_MAX
         };
 
-        const uint8_t maxRetries = 5;
+    private:
+        const uint8_t c_maxRetries = 5;
+        const uint32_t c_minDelay = 500;
         const uint16_t REG_TEMP = 0x0000;
         const uint16_t REG_TEMPCORR = 0x0008;
 
@@ -41,9 +43,13 @@ namespace drivers
 
         const uint8_t getNum();
 
+    private:
+        void delayRequest();
+
     private:
         const uint8_t m_address;
         uint8_t m_sensors;
         MODBUS &m_bus;
+        uint32_t m_lastRequest;
     };
 }