In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Tom M wrote:

I'm having a problem with SX Resetting itself in an Electrically Noisy Machine Environment.

I'm using SX48 and SX28 to control a large hydraulic press.
I'm activating two large solenoid valves that control the direction of a hydraulic cylinder.
This is a circuit that allows control of the Up and Down Limits of the Cylinders Ram.
It utilizes a Glass Scale for Position Feedback.

When I first tested the setup, I found that the SX would reset almost every time I turn off one of the solenoids.
So I've redesigned with the following ...

Added Optical Isolation to Inputs from the Glass Scale.
Added Optical Isolation to the two Relay Drivers that in turn switch the solenoids On/Off.
All circuitry is Isolated from the Chassis.
All Cable Shields are connected to Chassis.
AC Power Ground is connected to Chassis.  ( By Chassis I mean the Enclosures. )
The Machine, its Electrical Box, the SX Control Box, and Relay Box are all grounded together.
The 5V DC SX Power supply supplied from a wall transformer and regulated with a 3-terminal regulator with a large Filter Cap.
The Glass Scale is powered from it's own wall transformer.
And the Relays are powered from their own wall transformers.
None of these circuits are connected in any way.
The Wall Transformers Outputs and all wiring to and from the control circuit, wrap through Large Ferrite Cylinders.
All IC's and the SX are Bypassed by 0.1uf caps.
The SX uses a 16 mhz crystal.
The SX Control Unit is in it's own Die Cast Aluminum box, separated from the box containing the Relay Drivers and Electrics.

The Reset Rate has decreased to once in every hundred or so operations.

I need to get this to zero resets, for safety reasons if nothing else.

Any recommendations or anyone have experience in industrial machine control?

Thanks All.

Tom M.

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