From 5be6f437eed213cdfec5b82e5b4a12af5cc367c3 Mon Sep 17 00:00:00 2001
From: Jonathan McCrohan <jmccrohan@gmail.com>
Date: Sun, 25 Mar 2012 00:48:46 +0000
Subject: modbuslog: move exclusively to numbytes

---
 src/modbuslog.c   | 49 +++++++++++++++++++++++++++++++------------------
 src/modbuslog.cfg | 14 +++++++-------
 2 files changed, 38 insertions(+), 25 deletions(-)

diff --git a/src/modbuslog.c b/src/modbuslog.c
index d42a024..910e53f 100644
--- a/src/modbuslog.c
+++ b/src/modbuslog.c
@@ -184,13 +184,13 @@ int main(int argc, char *argv[]) {
 			config_setting_lookup_int(register_element, "registertype",
 					&registertype);
 
-			int startaddress;
-			config_setting_lookup_int(register_element, "startaddress",
-					&startaddress);
+			int startbyte;
+			config_setting_lookup_int(register_element, "startbyte",
+					&startbyte);
 
-			int numregisters;
-			config_setting_lookup_int(register_element, "numregisters",
-					&numregisters);
+			int numbytes;
+			config_setting_lookup_int(register_element, "numbytes",
+					&numbytes);
 
 			const char *intervalunit;
 			config_setting_lookup_string(register_element, "intervalunit",
@@ -228,30 +228,36 @@ int main(int argc, char *argv[]) {
 					// if connection fails, skip rest of loop
 					syslog(
 							LOG_ERR,
-							"Skipping read from slaveid=[%i], registertype=[%i], startaddress=[%i], numregisters=[%i]",
-							slaveid, registertype, startaddress, numregisters);
+							"Skipping read from slaveid=[%i], registertype=[%i], startbyte=[%i], numbytes=[%i]",
+							slaveid, registertype, startbyte, numbytes);
 					continue;
 				}
 
 				int retry = 0;
 
+				// convert bytes to registers
+				int nummodbusregisters;
+				nummodbusregisters = (((numbytes-1)/2)+1);
+
+				int startmodbusregister;
+				startmodbusregister = (startbyte/2);
 				// handle timeouts and retries
 				do {
 					switch (registertype) {
 
 					case 3:
-						rc = modbus_read_registers(ctx, startaddress,
-								numregisters, tab_reg);
+						rc = modbus_read_registers(ctx, startmodbusregister,
+								nummodbusregisters, tab_reg);
 						break;
 
 					case 4:
-						rc = modbus_read_input_registers(ctx, startaddress,
-								numregisters, tab_reg);
+						rc = modbus_read_input_registers(ctx, startmodbusregister,
+								nummodbusregisters, tab_reg);
 						break;
 
 					default:
-						rc = modbus_read_registers(ctx, startaddress,
-								numregisters, tab_reg);
+						rc = modbus_read_registers(ctx, startmodbusregister,
+								nummodbusregisters, tab_reg);
 						break;
 					}
 					if (rc == -1) {
@@ -305,16 +311,23 @@ int main(int argc, char *argv[]) {
 				int p;
 
 				// data arrives in words, split into bytes
-				for (p = 0; p < numregisters; p++) {
+				for (p = 0; p < nummodbusregisters; p++) {
 					MODBUS_SET_INT16_TO_INT8(byte, p * 2, tab_reg[p]);
 					//registervalue += tab_reg[i] + tab_reg[i + 1];
 				}
 
 				// bitshifting magic
-				switch (numregisters*2) {
+				switch (numbytes) {
+				case 1:
+					registervalue = byte[0];
+					break;
 				case 2:
 					registervalue = ((byte[0]) << 8) + byte[1];
 					break;
+				case 3:
+					registervalue = ((byte[0]) << 16) + ((byte[1]) << 8)
+							+ byte[2];
+					break;
 				case 4:
 					registervalue = ((byte[0]) << 24) + ((byte[1]) << 16)
 							+ ((byte[2]) << 8) + byte[3];
@@ -369,7 +382,7 @@ int main(int argc, char *argv[]) {
 						intervalid, utc.tm_year + 1900, utc.tm_mon + 1,
 						utc.tm_mday, utc.tm_hour, utc.tm_min, utc.tm_sec,
 						lc.tm_year + 1900, lc.tm_mon + 1, lc.tm_mday,
-						lc.tm_hour, lc.tm_min, lc.tm_sec, slaveid, startaddress,
+						lc.tm_hour, lc.tm_min, lc.tm_sec, slaveid, startbyte,
 						registervalue);
 				fclose(filehandle);
 
@@ -379,7 +392,7 @@ int main(int argc, char *argv[]) {
 						intervalid, utc.tm_year + 1900, utc.tm_mon + 1,
 						utc.tm_mday, utc.tm_hour, utc.tm_min, utc.tm_sec,
 						lc.tm_year + 1900, lc.tm_mon + 1, lc.tm_mday,
-						lc.tm_hour, lc.tm_min, lc.tm_sec, slaveid, startaddress,
+						lc.tm_hour, lc.tm_min, lc.tm_sec, slaveid, startbyte,
 						registervalue);
 
 				modbus_close(ctx);
diff --git a/src/modbuslog.cfg b/src/modbuslog.cfg
index 56a5d10..4cc7c35 100644
--- a/src/modbuslog.cfg
+++ b/src/modbuslog.cfg
@@ -23,7 +23,7 @@ reading= (
 			slaveid = 1;
 			registertype = 4;
 			startaddress = 0;
-			numregisters = 2;
+			numbytes = 2;
 			intervalvalue = 1;
 			intervalunit = "m";
 		},
@@ -31,7 +31,7 @@ reading= (
 			slaveid = 1;
 			registertype = 4;
 			startaddress = 2;
-			numregisters = 2;
+			numbytes = 2;
 			intervalvalue = 1;
 			intervalunit = "m";
 		},
@@ -39,7 +39,7 @@ reading= (
 			slaveid = 1;
 			registertype = 4;
 			startaddress = 4;
-			numregisters = 2;
+			numbytes = 2;
 			intervalvalue = 1;
 			intervalunit = "m";
                 },
@@ -47,7 +47,7 @@ reading= (
 			slaveid = 1;
 			registertype = 4;
 			startaddress = 6;
-			numregisters = 2;
+			numbytes = 2;
 			intervalvalue = 1;
 			intervalunit = "m";
                 },
@@ -55,7 +55,7 @@ reading= (
 			slaveid = 1;
 			registertype = 4;
 			startaddress = 8;
-			numregisters = 2;
+			numbytes = 2;
 			intervalvalue = 1;
 			intervalunit = "m";
                 },
@@ -63,7 +63,7 @@ reading= (
 			slaveid = 1;
 			registertype = 4;
 			startaddress = 10;
-			numregisters = 2;
+			numbytes = 2;
 			intervalvalue = 1;
 			intervalunit = "m";
                 },
@@ -71,7 +71,7 @@ reading= (
 			slaveid = 1;
 			registertype = 4;
 			startaddress = 14;
-			numregisters = 2;
+			numbytes = 2;
 			intervalvalue = 1;
 			intervalunit = "m";
                 }
-- 
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