More work building the memory loading tool,

 REWIRED PROG START AND LOAD IAR BUTTONS TO RELAY BOARD

The Prog Start (Program Start) is the button that triggers a step or begins running a program. It also triggers a memory load or display when the rotary mode switch is in the Load or Display positions. This button switches +12V between two logic signals.  A pair of relays on the eight relay board will disrupt the usual connections and cause the switch to appear pressed when active regardless of the state of the button. When not activated the relays leave the button free to operate normally.

The Load IAR button has one set of contacts feeding a single signal output, thus it requires only one of the remaining relays on the relay board. Rather than switching +12V, this is connected to part of the rotary mode switch so that it gets 12V only when the machine is in the Display or Load modes. 

Back of Prog Start and Load IAR button switches

This does leave five relay positions open for future expansion. I have no immediate plans for any other button control by the Arduino. I removed the signal wires from the two switches, extended the leads and connected them to the relay board. 

CONSTRUCTING MORE OF THE MEMORY LOAD TOOL

Near the two relay boards controlled the CES, I mounted the small PCB with the 470 ohm resistors. This provides +12V through the relay when it is activated. Small runs of wire stretch between the relay boards and the resistor board, plus one larger wire is connected to the +12V source nearby. 

Resistor board wired up, laced and installed on 1130

Routing the wires, dressing them and lacing it to make things neat takes time but produces a nicer and more reliable result. I spent hours completing all of this, leaving only the project box side and the signal cables from Arduino to relay boards. I expect to receive the 7805 voltage regulator soon and can complete the shield that fits to the Arduino Mega

All wiring to the 1130 is complete

The cabling between Arduino shield and relay boards needs to be carefully built and neatly laced, started with a solder joint at the shield and ending in a 10 position connector for each relay board. I will be away for a couple of days, then get back to the slow work finishing off this tool and putting it to use.

Plastic guard in place around CES wires