--- a/modbus/mb_runtime.h Thu Aug 13 19:00:38 2020 +0100
+++ b/modbus/mb_runtime.h Mon Dec 21 22:35:07 2020 +0000
@@ -147,7 +147,8 @@
u16 address;
u16 count;
int retries;
- u8 error_code; // modbus error code (if any) of current request
+ u8 mb_error_code; // modbus error code (if any) of last executed request
+ u8 tn_error_code; // transaction error code (if any) of last executed request
int prev_error; // error code of the last printed error message (0 when no error)
struct timespec resp_timeout;
u8 write_on_change; // boolean flag. If true => execute MB request when data to send changes
@@ -157,30 +158,43 @@
u16 coms_buffer[REQ_BUF_SIZE];
pthread_mutex_t coms_buf_mutex; // mutex to access coms_buffer[]
/* boolean flag that will be mapped onto a (BOOL) located variable
- * (u16 because IEC 61131-3 BOOL are mapped onto u16 in C code! )
+ * (u8 because IEC 61131-3 BOOL are mapped onto u8 in C code! )
* -> allow PLC program to request when to start the MB transaction
* -> will be reset once the MB transaction has completed
*/
- u16 flag_exec_req;
+ u8 flag_exec_req;
/* flag that works in conjunction with flag_exec_req
- * (does not really need to be u16 as it is not mapped onto a located variable. )
+ * (does not really need to be u8 as it is not mapped onto a located variable. )
* -> used by internal logic to indicate that the client thread
* that will be executing the MB transaction
* requested by flag exec_req has already been activated.
* -> will be reset once the MB transaction has completed
*/
- u16 flag_exec_started;
- /* flag that will be mapped onto a (WORD) located variable
- * (u16 because the flag is a word! )
- * -> MSByte will store the result of the last executed MB transaction
+ u8 flag_exec_started;
+ /* flag that will be mapped onto a (BYTE) located variable
+ * (u8 because the flag is a BYTE! )
+ * -> will store the result of the last executed MB transaction
* 1 -> error accessing IP network, or serial interface
* 2 -> reply received from server was an invalid frame
* 3 -> server did not reply before timeout expired
- * 4 -> server returned a valid error frame
- * -> if the MSByte is 4, the LSByte will store the MB error code returned by the server
+ * 4 -> server returned a valid Modbus error frame
* -> will be reset (set to 0) once this MB transaction has completed sucesfully
- */
- u16 flag_exec_status;
+ *
+ * In other words, this variable is a copy of tn_error_code, reset after each request attempt completes.
+ * We map this copy (instead of tn_error_code) onto a located variable in case the user program decides
+ * to overwrite its value and mess up the plugin logic.
+ */
+ u8 flag_tn_error_code;
+ /* flag that will be mapped onto a (BYTE) located variable
+ * (u8 because the flag is a BYTE! )
+ * -> if flag_tn_error_code is 4, this flag will store the MB error code returned by the MB server in a MB error frame
+ * -> will be reset (set to 0) once this MB transaction has completed succesfully
+ *
+ * In other words, this variable is a copy of mb_error_code, reset after each request attempt completes.
+ * We map this copy (instead of mb_error_code) onto a located variable in case the user program decides
+ * to overwrite its value and mess up the plugin logic.
+ */
+ u8 flag_mb_error_code;
} client_request_t;