Hi joseph
Search the web for EMI.
few points to take into considerations:
1. use grounded metal case.
2. make a compartment inside the case with feed through capacitors to capture EMI in.
3. all i/o signals or power lines must be supplied with emi filters inside the case.
4.Ferrite beads should be placed on wires.
i used power supply filters BNX002-01 and signal filter (cant recall part number).
5. Special consideration in PCB design, like keeping signal tracks away from power supply zone specially if its SMPS. and making multilayer board with ground plane and vcc plan(s).
Best Regards
Mahmood