Camstore COM Trouble Shooting

Rybett Controls WebDoc 204   (Copyright 2008)   Return to [Index]

The Camstore/COM consists of a combination control panel and CPU module mounted on the wall of the NC control cabinet. A mode switch, 2 reset buttons and several LED lamps provide control. An AC cord and uP cable feed through a cutout to pass power and data. The uP cable connects to a tape reader interface card on the inside of the cabinet. The following trouble shooting techniques use the Mode Switch to select between test functions.

BYPASS MODE is the least demanding:

Reader Bypass (quickly press Reset buttons) checks proper operation of the BTR interface card. Place a tape in the old reader and run the machine from tape. Failure in this mode may be qualified by removing the black Camstore uP cable and capping the uP interface plug with the white Molex Deadhead Connector. Failure in Deadhead condition is almost surely a BTR interface card fault. You may replace the interface card (or remove and replug wiring until one is available). If Reader Bypass fails but the Deadhead test works, the interface card is good and the Camstore computer has failed.

Serial Port Bypass (hold both Reset buttons for more than 2 seconds) checks the remote RS232/422 port. An ASCII S and CR are sent out the port and are expected to be echoed. Jumper remote port pins 2 to 3 and 4 to 5 to echo RS232 signals. (Additionally jumper remote port pins 15 to 16 and 17 to 18 for RS422 signals.) A solid green light indicates a good port. A flashing green light indicates a bad port (or bad jumpers). No green light suggests deeper problems.

LOCAL MODE checks all hardware except the serial ports:

Local Load (hold Reset for more than 2 seconds) loads a tape into Camstore memory. Flashing errors may be caused by a poor or torn tape, improper EIA/ASCII format or a Camstore memory that is faulty or too small for the loaded part program. Standard Camstore RAM is 100 feet of equivalent paper tape.

Local Run (momentarily press the Reset buttons) may be used only after a successful memory load. Failure in this mode may be due to improper EIA/ASCII format, expected reader speed, parenthetic data, Camstore BTR port problems or a failure in the NC machine control.

REMOTE MODE checks the link to your DNC computer:

Setting the Mode Switch to Remote and pressing Reset will cause the Camstore to output a SRT start code and wait for an echo and a legal mode exit command. The green Indicator Lamp will not light until a proper exit sequence has been received.

Quickly pressing Reset places Camstore into the standard Remote mode. Holding Reset for more than 2 seconds brings up Fanuc emulation mode whereby Camstore initiates a download just like a Fanuc CNC control.

HARDWARE REMOVAL as a diagnostic tool:

1. Load Camstore memory from tape and Run Camstore memory.
2. Switch to Reader Bypass and run from tape.
3. Remove the Camstore, Deadhead the uP plug and run tape.
4. Remove the BTR interface and replug the original wiring.


The following are common problems with very simple solutions. (When working inside of any electrical equipment, unplug AC power before removing lids or opening doors.)

1. Fanuc control will not run from Camstore memory.

You must place the Fanuc Auto/Manual switch on the tape reader in the Auto position. Sometimes a Fanuc 3000C control will change overnight from ASCII/ISO to EIA or vice/versa. Change the Camstore ASCII/EIA DIP switch Sw5 to match the Fanuc setup. Make sure the BTR ribbon cables are properly seated, oriented and keyed.

2. Lightning struck nearby and the DNC went down.

Replace the RS232 driver chips in the Camstore (IC part numbers 1488 and 1489 are very common). Then replace the COM port card in the DNC PC computer. Run loopback software/hardware tests if you can. Buy a Rybett Surge Kit to protect against future strikes.

3. I upgraded computers and the DNC software quit working.

Make sure your new computer has good serial COM ports. Run loopback software/hardware tests to identify and test the COM ports. Make sure a conflicting mouse driver is not unintentionally launched by your boot files. Note that ports COM1 and COM3 are not independent and share a common IRQ line. Same problem with COM2 and COM4. The DOS MODE command is used by Rybett DNC software. Make sure you have not installed an older version of MODE on your new computer. Set a PATH statement to the DOS directory.