user59849: I am using arduino mega with LCD 4X20 character to measure weight by 40 kg load cell and pt 100 to measure the temp. I have 4 output to 4 relay module. all are powered from 12vdc /3 amp Power supply.. 
the problem is.. the display started normally showing every thing perfectly.. but when the output comes out and the loads runs.. random characters appear 
is the power supply is not enough? or another problem.. 
Please advice. 

user59680: I'd suspect that it is a software error. Did you check your circuit if it induces desync between the Arduino and the LCD, or did you just use the wrong drivers?

user-1: Random Characters can Happen in several ways.

Check the Wires for: Loosen Ends; Broken Wires and Wrong Pin Connections.
Check your Code.


59849: <p>I am using arduino mega with LCD 4X20 character to measure weight by 40 kg load cell and pt 100 to measure the temp. I have 4 output to 4 relay module. all are powered from 12vdc /3 amp Power supply.. 
the problem is.. the display started normally showing every thing perfectly.. but when the output comes out and the loads runs.. random characters appear 
is the power supply is not enough? or another problem.. 
Please advice. <img src="https://i.stack.imgur.com/fg3A9.jpg" alt="enter image description here"><img src="https://i.stack.imgur.com/Mf0en.jpg" alt="enter image description here"></p>
 59680: <p>I'd suspect that it is a software error. Did you check your circuit if it induces desync between the Arduino and the LCD, or did you just use the wrong drivers?</p>
 -1: <p>Random Characters can Happen in several ways.</p>
<ul>
<li>Check the Wires for: Loosen Ends; Broken Wires and Wrong Pin Connections.</li>
<li>Check your Code.</li>
</ul>
