Notes
Once installed, the device will set up an SoftAP wifi network. The device will create a WiFi network displayed as ESP-RTU-XXXXXX. The default password is rtuadmin1. Once connected, navigate to the page located at http://192.168.42.43 which will take you to the administration of the device.
WiFi is set to turn off after 15 minutes to allow setup and configuration. After that, the WiFi is diabled for security. In order to re-enable WiFi, the device will need to be rebooted by either cycling power or pressing the boot button.
LED Indication
WiFi active: double-blink
Cellular not ready: fast blink
MQTT not connected: slow blink
PLC not responding (no successful reads for 30s): triple-blink
Normal operation: heartbeat pulse
PLC serial port must be set up as DF1 Full Duplex. This app does not communicate half duplex.
Parts List
LilyGo Board: https://lilygo.cc/products/t-sim7600
Max232 Board: https://www.amazon.com/dp/B00LPK0Z9A?ref=ppx_yo2ov_dt_b_fed_asin_title