#445 fixed PPM undefined field logic and improved RTU unit fault handling

rtu/rtu.lua

@@ -67,9 +67,11 @@ function rtu.load_config()
     return cfv.valid()
 end
 
--- create a new RTU unit
+-- create a new RTU unit<br>
+-- if this is for a PPM peripheral, auto fault clearing MUST stay enabled once access begins
 ---@nodiscard
-function rtu.init_unit()
+---@param device table|nil peripheral device, if applicable
+function rtu.init_unit(device)
     local self = {
         discrete_inputs = {},
         coils = {},
@@ -86,6 +88,10 @@ function rtu.init_unit()
     ---@class rtu
     local protected = {}
 
+    -- function to check if the peripheral (if exists) is faulted
+    local function _is_faulted() return false end
+    if device then _is_faulted = device.__p_is_faulted end
+
     -- refresh IO count
     local function _count_io()
         self.io_count_cache = { #self.discrete_inputs, #self.coils, #self.input_regs, #self.holding_regs }
@@ -112,9 +118,8 @@ function rtu.init_unit()
     ---@param di_addr integer
     ---@return any value, boolean access_fault
     function public.read_di(di_addr)
-        ppm.clear_fault()
         local value = self.discrete_inputs[di_addr].read()
-        return value, ppm.is_faulted()
+        return value, _is_faulted()
     end
 
     -- coils: single bit read-write
@@ -133,9 +138,8 @@ function rtu.init_unit()
     ---@param coil_addr integer
     ---@return any value, boolean access_fault
     function public.read_coil(coil_addr)
-        ppm.clear_fault()
         local value = self.coils[coil_addr].read()
-        return value, ppm.is_faulted()
+        return value, _is_faulted()
     end
 
     -- write coil
@@ -143,9 +147,8 @@ function rtu.init_unit()
     ---@param value any
     ---@return boolean access_fault
     function public.write_coil(coil_addr, value)
-        ppm.clear_fault()
         self.coils[coil_addr].write(value)
-        return ppm.is_faulted()
+        return _is_faulted()
     end
 
     -- input registers: multi-bit read-only
@@ -163,9 +166,8 @@ function rtu.init_unit()
     ---@param reg_addr integer
     ---@return any value, boolean access_fault
     function public.read_input_reg(reg_addr)
-        ppm.clear_fault()
         local value = self.input_regs[reg_addr].read()
-        return value, ppm.is_faulted()
+        return value, _is_faulted()
     end
 
     -- holding registers: multi-bit read-write
@@ -184,9 +186,8 @@ function rtu.init_unit()
     ---@param reg_addr integer
     ---@return any value, boolean access_fault
     function public.read_holding_reg(reg_addr)
-        ppm.clear_fault()
         local value = self.holding_regs[reg_addr].read()
-        return value, ppm.is_faulted()
+        return value, _is_faulted()
     end
 
     -- write holding register
@@ -194,9 +195,8 @@ function rtu.init_unit()
     ---@param value any
     ---@return boolean access_fault
     function public.write_holding_reg(reg_addr, value)
-        ppm.clear_fault()
         self.holding_regs[reg_addr].write(value)
-        return ppm.is_faulted()
+        return _is_faulted()
     end
 
     -- public RTU device access