Denford Software & Machines

Hello everyone,

I have a 1990 Triac ATC with a bit of an issue that I was hoping someone might be able to give me some troubleshooting ideas on.

If the machine has been sitting for a few hours I can power it up, hit the drive on button, datum the machine out and all is good for around 5 to 15 minutes. After the 5 to 15 minutes, if I try to do a tool change or datum the machine again I get a "Tool Change Error" alarm. I can reset the alarm, but I get it again as soon as I try to do anything. I have to power the machine down for a few hours before I can get it to datum out again, only to have the same problem all over again.

Here is what I have noticed. Any idea on what could be causing the alarm would be very helpful.

1. When the machine is alarm free for the first few minutes the LED status light on the rear ATC control box door is a nice healthy blink on/off every half second or so. After the alarm has occured the light is steady off, and even resetting the alarm won't bring the light back to blinking. Only after the machine sitting powered off for a few hours will the light blink again.

2. When I first power the machine on, the main screen has the text "AUX INPUT" at the top left. When I hit the drive on button a 3 appears next to "AUX INPUT", and the machine asks me to "Press (ABS DATUM) to datum machine". Machine datums fine and all is good to go. After the alarm has occured I hit the drive on button, and I get "Press (ABS DATUM) to datum machine" but the 3 doesn't show up by "AUX INPUT". If I try to datum the machine I get the "TOOL CHANGER ERROR" alarm.

Any help would be much appreaciated. Thanks

Searching the forum I found the info below talking about the dip switched in the rear cabinet. If I understand it correctly when I put switch 8 to ON, the machine powers on in hardware test mode(not sure what it is exactly). Not knowing what else to try I put switch 8 ON and everything else off (the original switch settings was everything off except 7). With switch 8 ON the Aux Input 3 always comes on. I can ABS datum the machine, then it askes me to place all tools in the tool changer and hit ENTER. The machine moves to the tool change point and the spindle spins for a few seconds like it is going to do a tool change, then I get the "Tool Change Error" alarm.

Does anybody know what the hardware test mode is used for? Any ideas what to try next? Any ideas at all would be much appreaciated. Thanks

SW 8 – Hardware Test Mode Select

If SW8 set On at Power Up SW4 to 1 are used as follows:-
SW4 SW3 SW2 SW1
Off Off Off Off - Not Used
Off Off Off On - Not Used
Off Off On Off - Read/Transmit status of Datums/Inputs
Off Off On On - Read/Transmit status of Overtravels/Link 1, 2
Off On Off Off - Read/Transmit status of Assign Switches
Off On Off On - Read/Transmit status of Ext. Keypad
Off On On Off - Read/Transmit status of Ext. Stop Drive Flts
Off On On On - Sequence Aux 1 to 4 and Spdl relays/LED
On Off Off Off - Execute Auto Test
On Off Off On - Do a 3 axis move
On Off On Off - Ramp D to A output
On Off On On - Checksum ROM and transmit checksum
On On Off Off - Test External RAM (if fitted)
On On Off On - Read/Transmit status of inputs 5 to 12
On On On Off - Sequence Aux 5 to 12
On On On On - Sequence Aux 13 to 20

If SW8 is Off:-
SW7 selects RS232 data transmission from controller if On
SW6 selects either ROM (if On) or RAM program execution from keypad
SW5 selects continuous program execution (if On) or wait for Start between program executions if Off.
On systems with battery backed RAM SW4 to 1 are not used.
On systems without battery backed RAM SW4 to 1 are used as follows:
SW4 selects parity checking of input RS232 data if ON
SW3 selects either Odd (if On) or Even parity for received and transmitted RS232 data
SW2 & SW1 select RS232 baud rate as follows:-
SW2 SW1 Baud Rate
Off Off 300
Off On 1200
On Off 4800
On On 9600

I'm not sure how far we'd get trying to diagnose this using the switches - if it worked previously and nothing has changed (except its age) then it's a good start and you need to do some basic checks.

It sounds to be temperature related and I'd just be tempted to look for:
poor/corroded contacts on connectors and chips (remove and clean any contacts you can find)
voltages levels too high or low (check transformer tappings)
components getting too hot (it'd be worth keeping the cabinet cool with a fan or something to see if it runs for longer)
after that i'd start looking for broken wires relating to the toolchanger and testing each of the switches/motors/solenoids

How about checking the arm in/out & arm up/down limit switches. Also from what I remember the arm should drop down momentarily while the datum procedure is being performed.