[collectd] [PATCH] add Modbus/RTU support to modbus plugin
Eric Sandeen
sandeen at sandeen.net
Fri Nov 7 06:50:20 CET 2014
This allows access to a local RS-485 serial port
via the modbus plugin by specifying i.e.
Device "/dev/ttyUSB0"
Baudrate 38400
in the <Host> block.
For now it assumes 8N1, I don't know if there's any
reason to support less common serial configs...
Signed-off-by: Eric Sandeen <sandeen at sandeen.net>
---
This applies after my previous patch.
I realize I forgot to add config examples to the comment
block in my prior patch, feel free to add those, or I can
re-send if you like.
diff --git a/src/modbus.c b/src/modbus.c
index b90266e..926f9eb 100644
--- a/src/modbus.c
+++ b/src/modbus.c
@@ -56,6 +56,10 @@
* <Host "name">
* Address "addr"
* Port "1234"
+ * # Or:
+ * # Device "/dev/ttyUSB0"
+ * # Baudrate 38400
+ * # (Assumes 8N1)
* Interval 60
*
* <Slave 1>
@@ -84,6 +88,14 @@ enum mb_register_cmd_e /* {{{ */
REG_CMD_READ_INPUT
}; /* }}} */
typedef enum mb_register_cmd_e mb_register_cmd_t;
+
+enum mb_conntype_e /* {{{ */
+{
+ MB_TCP,
+ MB_RTU
+}; /* }}} */
+typedef enum mb_conntype_e mb_conntype_t;
+
struct mb_data_s;
typedef struct mb_data_s mb_data_t;
struct mb_data_s /* {{{ */
@@ -109,9 +121,11 @@ typedef struct mb_slave_s mb_slave_t;
struct mb_host_s /* {{{ */
{
char host[DATA_MAX_NAME_LEN];
- char node[NI_MAXHOST];
+ char node[NI_MAXHOST]; /* host or device */
/* char service[NI_MAXSERV]; */
- int port;
+ int port; /* Modbus/TCP */
+ int baudrate; /* Modbus/RTU */
+ mb_conntype_t conntype;
cdtime_t interval;
mb_slave_t *slaves;
@@ -301,21 +315,33 @@ static int mb_init_connection (mb_host_t *host) /* {{{ */
/* We'll do the error handling ourselves. */
modbus_set_error_handling (&host->connection, NOP_ON_ERROR);
- if ((host->port < 1) || (host->port > 65535))
- host->port = MODBUS_TCP_DEFAULT_PORT;
+ if (host->conntype == MB_TCP)
+ {
+ if ((host->port < 1) || (host->port > 65535))
+ host->port = MODBUS_TCP_DEFAULT_PORT;
+
+ DEBUG ("Modbus plugin: Trying to connect to \"%s\", port %i.",
+ host->node, host->port);
- DEBUG ("Modbus plugin: Trying to connect to \"%s\", port %i.",
- host->node, host->port);
+ modbus_init_tcp (&host->connection,
+ /* host = */ host->node,
+ /* port = */ host->port);
+ }
+ else
+ {
+ DEBUG ("Modbus plugin: Trying to connect to \"%s\".", host->node);
- modbus_init_tcp (&host->connection,
- /* host = */ host->node,
- /* port = */ host->port);
+ modbus_init_rtu (&host->connection,
+ /* device = */ host->node,
+ /* baudrate = */ host->baudrate,
+ 'N', 8, 1, 0);
+ }
status = modbus_connect (&host->connection);
if (status != 0)
{
ERROR ("Modbus plugin: modbus_connect (%s, %i) failed with status %i.",
- host->node, host->port, status);
+ host->node, host->port ? host->port : host->baudrate, status);
return (status);
}
@@ -336,17 +362,32 @@ static int mb_init_connection (mb_host_t *host) /* {{{ */
if (host->connection != NULL)
return (0);
- if ((host->port < 1) || (host->port > 65535))
- host->port = MODBUS_TCP_DEFAULT_PORT;
+ if (host->conntype == MB_TCP)
+ {
+ if ((host->port < 1) || (host->port > 65535))
+ host->port = MODBUS_TCP_DEFAULT_PORT;
- DEBUG ("Modbus plugin: Trying to connect to \"%s\", port %i.",
- host->node, host->port);
+ DEBUG ("Modbus plugin: Trying to connect to \"%s\", port %i.",
+ host->node, host->port);
- host->connection = modbus_new_tcp (host->node, host->port);
- if (host->connection == NULL)
+ host->connection = modbus_new_tcp (host->node, host->port);
+ if (host->connection == NULL)
+ {
+ ERROR ("Modbus plugin: Creating new Modbus/TCP object failed.");
+ return (-1);
+ }
+ }
+ else
{
- ERROR ("Modbus plugin: Creating new Modbus/TCP object failed.");
- return (-1);
+ DEBUG ("Modbus plugin: Trying to connect to \"%s\", baudrate %i.",
+ host->node, host->baudrate);
+
+ host->connection = modbus_new_rtu (host->node, host->baudrate, 'N', 8, 1);
+ if (host->connection == NULL)
+ {
+ ERROR ("Modbus plugin: Creating new Modbus/RTU object failed.");
+ return (-1);
+ }
}
modbus_set_debug (host->connection, 1);
@@ -358,7 +399,7 @@ static int mb_init_connection (mb_host_t *host) /* {{{ */
if (status != 0)
{
ERROR ("Modbus plugin: modbus_connect (%s, %i) failed with status %i.",
- host->node, host->port, status);
+ host->node, host->port ? host->port : host->baudrate, status);
modbus_free (host->connection);
host->connection = NULL;
return (status);
@@ -427,7 +468,7 @@ static int mb_read_data (mb_host_t *host, mb_slave_t *slave, /* {{{ */
{
status = EBADF;
}
- else
+ else if (host->conntype == MB_TCP)
{
struct sockaddr sockaddr;
socklen_t saddrlen = sizeof (sockaddr);
@@ -443,7 +484,7 @@ static int mb_read_data (mb_host_t *host, mb_slave_t *slave, /* {{{ */
status = mb_init_connection (host);
if (status != 0)
{
- ERROR ("Modbus plugin: mb_init_connection (%s/%s) failed. ",
+ ERROR ("Modbus plugin: mb_init_connection (%s, %s) failed. ",
host->host, host->node);
host->is_connected = 0;
host->connection = NULL;
@@ -489,7 +530,7 @@ static int mb_read_data (mb_host_t *host, mb_slave_t *slave, /* {{{ */
if (status != values_num)
{
- ERROR ("Modbus plugin: modbus_read_%sregisters (%s/%s) failed. status = %i, values_num = %i "
+ ERROR ("Modbus plugin: modbus_read_%sregisters (%s, %s) failed. status = %i, values_num = %i "
"Giving up.", data->register_cmd == REG_CMD_READ_INPUT ? "input_" : "",
host->host, host->node, status, values_num);
#if LEGACY_LIBMODBUS
@@ -917,6 +958,8 @@ static int mb_config_add_host (oconfig_item_t *ci) /* {{{ */
status = cf_util_get_string_buffer (child, buffer, sizeof (buffer));
if (status == 0)
status = mb_config_set_host_address (host, buffer);
+ if (status == 0)
+ host->conntype = MB_TCP;
}
else if (strcasecmp ("Port", child->key) == 0)
{
@@ -924,6 +967,14 @@ static int mb_config_add_host (oconfig_item_t *ci) /* {{{ */
if (host->port <= 0)
status = -1;
}
+ else if (strcasecmp ("Device", child->key) == 0)
+ {
+ status = cf_util_get_string_buffer (child, host->node, sizeof (host->node));
+ if (status == 0)
+ host->conntype = MB_RTU;
+ }
+ else if (strcasecmp ("Baudrate", child->key) == 0)
+ status = cf_util_get_int(child, &host->baudrate);
else if (strcasecmp ("Interval", child->key) == 0)
status = cf_util_get_cdtime (child, &host->interval);
else if (strcasecmp ("Slave", child->key) == 0)
@@ -940,9 +991,22 @@ static int mb_config_add_host (oconfig_item_t *ci) /* {{{ */
} /* for (i = 0; i < ci->children_num; i++) */
assert (host->host[0] != 0);
- if (host->host[0] == 0)
+ if (host->node[0] == 0)
{
- ERROR ("Modbus plugin: Data block \"%s\": No type has been specified.",
+ ERROR ("Modbus plugin: Data block \"%s\": No address or device has been specified.",
+ host->host);
+ status = -1;
+ }
+ if (host->conntype == MB_RTU && !host->baudrate)
+ {
+ ERROR ("Modbus plugin: Data block \"%s\": No serial baudrate has been specified.",
+ host->host);
+ status = -1;
+ }
+ if ((host->conntype == MB_TCP && host->baudrate) ||
+ (host->conntype == MB_RTU && host->port))
+ {
+ ERROR ("Modbus plugin: Data block \"%s\": You've mixed up RTU and TCP options.",
host->host);
status = -1;
}
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