Moxa ioPAC 8500-2-M12-C-T [31/66] Cellular api

Developer's Guide for Moxa RTU Controllers Programmer's Guide

2-23

Cellular API

Cellular API functions communicate with the internal cellular modem via two device nodes located at

/dev/ttyACM and /dev/ttyUSB0. Users must include libmoxa_pgm.h. Cellular API functions work in two

operating modes: Auto Reconnect as enabled or disabled. If Auto Reconnect is enabled, it automatically detects

the cellular connection failure via a ping command to a user-specified remote host periodically. Once a cellular

connection failure is detected, it will try to re-establish the cellular network without any interaction with the

user’s program. If auto Reconnect is disabled, the user’s program has total control of cellular connection and

disconnection; on the other hand, the program must detect the cellular network failure by itself. To apply these

two modes, cellular API functions are implemented as a state machine. The states of these two modes are

described in figures below.

#define MODEM_STATE_INIT 0

#define MODEM_STATE_READY 1

#define MODEM_STATE_CONNECTING 2

#define MODEM_STATE_CONNECTED 3

#define MODEM_STATE_DISCONNECT 4

Return values of cellular API functions are shown below; they can also be found at libmoxa_pgm.h.

#define MODEM_ERR_OK 0//successful

#define MODEM_ERR_INIT 1//not init

#define MODEM_ERR_PARAM 2//invalid parameter

#define MODEM_ERR_OPEN 3//open device error

#define MODEM_ERR_SIM 4//SIM card error

#define MODEM_ERR_PIN 5//PIN code error

#define MODEM_ERR_BAND 6//Set band error

#define MODEM_ERR_ECHO_OFF 7//turn off echo error

#define MODEM_ERR_CELLULAR_DENIED 8//register to cellular network is denied

#define MODEM_ERR_RESET 9//reset modem error

#define MODEM_ERR_THREAD 10//create thread error

#define MODEM_ERR_APN 11//set APN error

#define MODEM_ERR_CREDENTIAL 12//generate PPP credential file error

#define MODEM_ERR_ATTACH 13//attach to 3G network error

#define MODEM_ERR_IF 14//ppp interface is not established

#define MODEM_ERR_CMD 15//err command (wrong state, or previous cmd is executing)

#define MODEM_ERR_TIMEOUT 16//connect to 3G timeout (PPP)

#define MODEM_ERR_STATE 17//invalid cmd state

#define MODEM_ERR_BREAK 18//user break

#define MODEM_ERR_SEM 19//create named semaphore for modem failed