Introduction: How to Open and See What's Inside an HMI OP 320 Teardown
OP 320 HMI
is a monochrome graphic panel with 20 configurable keys. It's supposed manufacturer is XINJE Electric Co, but there is not a visual reference in the case nor in circuit boards. Its aspect is very similar to KINCO MD204L.
This HMI cost around 40 dollars (shipment included!), is powered by 24 V DC and have RS-232 and RS-422 communication interfaces, its programmed using the RS-232 port using a proprietary software. Have multiple industrial communication protocols. so is a very attractive solution to interface microcontroller based systems, because its integrated display, keyboard, control logic, using only a serial port, all encased in an "industrial like" case that the manufacturer claims to be IP65 for front panel.
Step 1: REQUIRED COMPONENTS
Here is the list for the required components for this project with the absolute lowest prices! If you find something cheaper somewhere, please msg me!
Step 2: TEARDOWN PROCESS
To open the OP 320 case a 2.4 mm x 40 mm Phillips screwdriver is required
First, remove 24V power terminal and release the 4 screws that holds the back case. Then pull the main board to disconnect from the display board, the boards are connected to a 20 pin single line connector.
Carefully disconnect the membrane keyboard connector (9 pin single line). This allows to totally disconnect the main board. The last step is to remove the spacer and the 3 screws that hold together the display board with the front panel.
Step 3: ELECTRONIC BOARDS AND MAIN COMPONENTS
MOST IMPORTANT SEMICONDUCTOR LIST IN MAIN BOARD
Part #: Description
Scratched info: Microcontroller, looking the package and pin arrangement, probably an MCS-51 compatible with onboard RAM and FLASH
LM2576S-5.0: SWITCHER 3A Step-Down Voltage Regulator
SP202EEN: Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers
74HC245D: octal transceiver featuring non-inverting 3-state bus compatible outputs in both send and receive directions7705ACintegrated-circuit supply-voltage supervisors
MAX 485: Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers
Step 4: DISPLAY BOARD
Part #: Description
JXD 19264ALCD: 192 x 64 graphic matrix display
7660: Switched capacitor voltage converter
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