Troubleshooting DIO, PIO and ASIOB

DIO Card

When you look at a DIO card you will see the connector in described order from left to right.

1. X29:

This connector is used for service purposes only. The DIO2 card on the Vision PC and NT uses this connector CAN BUS. Most connectors on both boards are identical.

2. X28:

This is a serial connector for UDL, PPT and DNC. X28 is divided in two different types of protocol. Pins 1,2,3 and 4 are for RS-485. RS-485 protocol has higher noise rejection and is more suitable for longer distances, 100 to 200 meters. RS-485 uses differential electrical signals for better electrical characteristics. Use a RS485 to RS-232 adapter. (Note: RS-232 is also referred to as RS-232C or V.24)

Pin 4,5,6 and 7 are for the RS-232 protocol and is most commonly used with fiber optical cable on modem connections of less than 100 meters. Fiber optic cable is the most reliable means of data communication. A lower cost option is a computer transfer cable, part number #2237223. This cable is a flex type, suitable for power track application.

A common complaint is "UDL DOES NOT WORK".

Here is some possible causes and how to identify them.

(a) Bad cable:

Check continuity of cable connection. Connection diagram is on most schematics on page 3 or 4. If continuity is ok, try reversing wires on pin 5 and pin 7.

(b) Software problem:

The maturity of the software module indicates this is rarely the problem. Factory testing eliminates still more problems. Check for port setting on control for:

• COM#3 for X29 connector, device; #04
• baud rate; 9600
• data bits; 8
• start/stop bit; 1, xon/xoff; 1, timeout; 020.

These can be found in the "DEV" constant editor.

Other things to check:

• Same parameters must be set at host software.
• Make sure file extension setting on host otherwise you will not be able to read directory of host.
• Control type. If you select wrong control type operation may be unreliable (intermittent) or not work at all.

(c) Port is bad:

Use COM check option from UDL or ANC45. You can jumper two ports and check communication loop. You can also use terminal mode (can be set in device constant). Use windows terminal to check COM loop. If the port is indicated as bad, the board must be replaced. Board replacement should be the last resort.

For Vision PC and Vision NT, you can also use COM1, pins2, 3, and 5 for your UDL connection. X28 connector on Vision PC is actually used as current loop port. X28 in this case is used for hand pendant. Connect to X28 when using hand pendant from Vision PC for NT hand pendent connect to MC COM#1(9 pin) or COM #2(25 pin)

A common problem is that DCE and DTE on fiber optic modem are not set correctly. They have to be crossed. This means if control end modem is set for DCE then host computer end modem must set to DTE. This will actually cross RX and TX terminals.

1. X27:

This connector is another serial port specified as COM#4 in device constant. This is strictly RS-485 protocol. Rarely used. If you have a pendent and UDL on Vision 2000c or 3000 then you may use it with RS485 to RS232 converter. Remember that whenever connecting two different devices, RX and TX must be crossed.

2. X26:

This is ASIOB1 BUS connector. It connects ATHC-3 or LCASIOB main board to CNC control. Refer to schematic for checking power and communication on this bus. There are LED’s to indicate bus operation. This is further discussed during ASIOB cards. You can check voltage between pin 3 and 4 for between 4.5 – 5.4 volts. If a scope or Fluke 87 multi-meter are available, check for pulses on pin 1 and 2

3. X25:

Input for operator panel. It is a serial connection so you cannot check many things. Check for loose connection. To check independent push button operation use Shift + F6 and then F1. A key map is displayed. A constantly dark button without being depressed is an indication that the button is stuck and may be the reason for control lockup. Try to correct it. If no luck, change operator panel. Send the panel into the ESAB Cutting Systems repair department. The panel should be replaced if any major repair is required.

4. X24:

Pin 1 and 2 is for operator panel e-stop. 3 and 4 are for e-stop relay k1 on DIO board. In the event of fatal error, this relay will open and you will have an e-stop. Some errors you will see are "Watchdog error", " ASIOB ATHC-3 error" or "battery checksum error". Reboot power to eliminate these error messages. If still if you receive an error, refer to the control manual and take appropriate action. Last option is to change the DIO2 board.

5. X23:

This is 24 VDC power input for isolated inputs and outputs. Power to PIO board will be supplied from here to X5 on PIO board.

6. X22:

Mostly 24vdc power connects here from external source. Internally it is jumped to X23

7. X21:

Digital input. You can check voltage here. If 24 volt is present on pin1 to pin 8, it is displayed on status screen as EPEP_0 to EPEP_7. If 24vdc is present on pin and you do not see EPEP as "1" you probably have an input driver bad. Change board. Some input can be forced to 1 to keep machine temporarily in production. Some input cannot be forced. MIP may be looking for signal to go on and off in particular step.

8. X20:

This is the direct output connector. Always use this connector for external output to drive a relay. Use very low current (200 mA) outputs. APAP_0 to APAP_7 output can be forced. Measure 24vdc at pin 1 to 8 for proper operation. If output is forced and 24 VDC is present on a pin, you may have bad output driver. Sometimes a diode on relay may be shorted. Check for a short in this case. Disconnect wire and measure again.

 

PIO Card

All encoder and drive connections are located on this card described here is left to right

1. X9:
2. This connector has +/- 10 VDC output for w-axis drive. Drive velocity command connect between pin 1 and 2. Pin 3 is shield connection for cable.
3. X8:

This connector has +/- 10 VDC output for X, Y and Y2 axis. Pin 1-2 for x, pin 4-5 for Y and pin 7-8 for Y2 axis. Normally you should have cable #2237223 for analog output connection. When using this cable make sure you have internal shield connected to one of the shield connections, pin 3, 6, and 8.

4. X7:

This is the reference switch input s connector, using digital (direct) 24 VDC inputs. Status can be monitored for these inputs with shift + F1 screen for Vision 3000 and down. It is displayed with other EPEP on PC and NT controls with shift + F2 screen

5. X6:

Drive allow signal comes from this connector. It also is 24-vdc direct output. You can check for drive allow signal with shift + F6 and F2 screen (status screen) on most controls. Drive allow signals will not be present if you have a drive error. All other times this signal should stay high.

6. X5:

24-vdc power for X7 and X6 is originates here. It should be connected to X23 of DIO with short jumper.

7. X4-X1:

These are encoder-input connections. Internal shield of encoder cable must be connected to pin #9 of corresponding connector or you will see lots of frequency errors. Also outer shield must be clamped to Vision ground bar. Voltage on pin 1 and 2 should be approximately 5.4 volts. If not, adjust power supply. Lower voltages will work but noise/signal level ratio is higher and may resulting frequency errors.

 

Common problems and causes for drive or machine motion problems.

NOTE: Always ensure drive gears are disengaged from drive rack when troubleshooting drives.

1. Always have drive error:
• Turn on service mode and go to drive calibration screen.
• Highlight drive letter in open loop and try to output voltage to 4.0 V.
• Check if drive is moving at all. If drive is not moving, check drive allow signal.
• If signal is high, check wiring and drive allow relay connections.
• If drive allow is good and drive is not moving, check output voltage on x8 or x9 connector.
• If you measure approximately 4.0 VDC and drive is not moving, the drive amp may be bad.
• Check for a fault light on the drive and refer to the manual.
• If drive is moving and your screen does not display but ½ the machine speed, either drive is not set correctly or you may have problem with encoder.
• To isolate encoder problem you can measure tach voltage to calculate speed. Most dc drives used have 14vdc output for 1000 rpm (for brushless drive you can measure speed on wago connector board. Refer to Yaskawa drive manual for pin-out and scale). Motor speed = tach voltage * 1000. Pinion speed = Motor speed / gear ratio. From this you can easily calculate linear speed of machine = 3.14 * pinion speed * pinion diameter.
• An encoder problem is the cause if speed is half of max machine speed.
• Check wiring first. If wiring is ok, then the problem is either a bad encoder or a bad connector at the PIO card.
• To isolate further, wire drive enable signal and analog output from another working axis to the one you have a problem with. Now also move problem encoder to other encoder-input plug. If it shows correct speed on display, you have bad connector on PIO card. Change PIO card.
• If it does not display correct speed on previously working axis, you have bad encoder cable or encoder.
  
2. Drive error at high speed in one direction:
• If you have a drive error at high speed, check by setting output voltage to 8.0 VDC in open loop. You should read max speed of machine. If not, then adjust input reference gain of drive until you see max speed.
• Now recheck at 4vdc. You should see ½ the machine speed.
• If not, you have drive linearity problem.
• If an error is present in only one direction, check speed in open loop window at –8 to +8 VDC. You should have close speed display in both directions and zero speed at 0 VDC.
• Adjust offset to get zero speed at zero volt.
• If offset is null and you get very different speeds, check voltage at +/- 8-volt output.
• If output is relatively close and you don’t speed close in each direction, then you will have to change drive amp.

Sometimes in the above cases (1 and 2), you will get ok result in open loop but still machine does not work.

This normally will suggest mechanical problem with the machine.

Many mechanical problems can be identified by measuring drive current.

In case of DC drives, you can wire ammeter in series with one of the motor leads. Now engage drive to machine and run machine up and down the rail.

Monitor current in both directions. This is also common method for using when you have "Gantry Error". This error may be coming from the fact that machine is way out of square.

When you are using Yaskawa brushless drives, you can measure current on wago connector (refer to drive manual for pin number and scaling).

Drive problem on x and w can be resolved by measuring current on both drives at the same time. Compare current reading. If readings are far apart, you must re-adjust mechanics before you try to adjust drive.

Another classic problem with drives is accuracy of machine.

• Use shift + F1 screen to solve this problem and monitor loop error.
• Loop error displayed is in terms of encoder pulses. To convert pulses to distance, check machine constant for x, y or w axis pulses/1000 inch constant. In no case should you see error more than +/-0.020 inch.
• If a larger error is seen on one axis, compare to other check drives.
• If difference is minor you can adjust loop gain for it.
• Excess drag is sometimes an issue on large machines with multiple plasma or 10 to 12 stations on the y axis, power track drag can be a problem. Increase gain to the drive to compensate. Always backup original constant in case you make large changes. Most gains are set at the factory so you must be extremely careful before changing them.

Another classic problem is machine is not square farther away from gantry alignment switch.

• This is normal indication of incorrect scale match between x and w axis pulses.
• First mechanically square machine and mark rail at both ends.
• Now reference machine and perform- gantry alignment procedure.
• Reference machine again.
• Now drive machine to square mark at end closer to gantry alignment switch.
• Readjust mc #81 if required. (Refer to page 31 of schematic for gantry alignment procedure).
• Now drive machine to the other end of rail and your square mark should match. If not, you have scale mismatch between x and w.
• Change pulses and repeat procedure until the square mark aligns with machine.

NOTE: You should be suspicious if x and w have same exact pulses at installation. It is highly unlikely two pieces of rail and rack will be identical.

Caution: If you change pulses more than 500 pulses you will have to rock drive then reference again.

(3) Main CPU board: If you have problem during initial boot sequence, you may have problem with motherboard. Check your power supply first. Sometimes a catastrophic failure of PIO or DIO boards can be loading power supply or ISA bus. Before ordering another CPU board, pull out these two cards and try to boot without them. You can also connect a keyboard and hold down F5 key and it will boot as regular dos computer. This does not apply to PC or NT. These will be discussed separately.

 

ASIOB Card

This only applies to standard ASIOB cards. LCASIOB is different.

1. ATHC3 card:

This card is a mini computer without keyboard and display. All other cards plug into this main board. Digital output card and analog output card communicate with this card using a serial bus. Servo card for the motors communicate through analog signal for motor velocity command. You can check many things.

1. Check power LED (green) for power supply for entire board.
• If green light is not on does not always mean power supply is bad.
• Before changing main board, check transformer and 120vac fuse on main board.
• Now check jumper on card (X10 and X11- use schematic for proper jumper setting). If they are ok and still no green light, disconnect all plug-in boards. One of these plug-ins may be bad and loading down main board power supply.
• If light comes back on after removing all the secondary boards, reconnect each card and recheck for the green LED. Replace the bad secondary card if the light goes out during this process.
• If green light is still not on you will have to change the ATHC3 card.
2. Power light is ok but yellow LED is flashing:
• This suggests you do not have communication between main board and CNC.
• First check all the stations.
• The ASIOB1 bus is not corrupted if some stations work.
• If all stations have flashing LED’s, then you should disconnect X35 from ATHC3 card and try one station at a time.
• If problem is not yet identified, then check wiring from X26 of DIO card to terminals to X35 of individual stations.
• You can also check for 5 volts between X26 of DIO or X35 of ATHC3 pin 3 and 4.
• If voltage between pin 3 and 4 drops below 4 volts you will have frequent communication loss. You can also check bus activity on pin 1 and 2 using scope or Fluke 87 in ~ACV in frequency mode. Possibility of all stations loosing communication at the same time is very remote. More likely, your problem is with X26 of DIO card.
• If only one or two stations are affected, the trouble leads to an individual card.
1. Station has error condition: This can be checked by individual BITI on shift + F2 screen. BITI_1 for station one and so on. These are conditions you may not receive BITI back to CNC
1. One of the limit switches is open:

If station is all the way up or down and one of the switches is open. These are normally closed inputs you can check on pin X6 3 and 4.

• You are supposed to have 15-18 VDC all the time until you reached limit switch. Check wiring.
• On stations w/o limit switches, has to have these inputs jumped to X6-1. Sometime jumpers are placed in station junction box.
• Another common problem you will encounter is that a limit switch may be stuck open. Check upper limit switch status in shift + F2 screen. BITI_129 for station one and BITI_130 for station 2 and so on. Lower limit switch does not have BITI coming back but you can still check switch reading in shift + F3 screen. Last column should display AF with B 252(check correct AF).
2. Station has crashed:

If station has crashed, you will not get BITI back. There is no specific input defined in CNC for this condition. Instead you will get AF 241 in shift + F3 screen in the last column. You must receive AF 241 in order for crash to work properly.

Check pressure switch and electrical soft touch circuit to solve crash problem.

Crash is connected between X8 pin 1 and 2 for normally closed pressure switch. It is connected between pin x8 2 and 3 for normally open switch. When using normally open pressure switch you must have a 1k resistor between pin x8 1 and 2. X8 is located on ATHC3 main board. This is also a 15-18 VDC signal if you want to check it using a multimeter. Crash is a dual-purpose signal. This signal is also a plate detect signal. During touch cycle, ATHC3 hardware automatically regards this signal as plate detect. CNC will receive AF 255 when touch cycle is complete. You can check AF 255 in shift + F3 screen last column. MIP looks for this signal before sending start signal to power supply. Therefore, if you have situation where there is no power supply start signal, you may not be getting back AF 255. If hardware has trouble making touch, it will instead send AF 254 (again shift + F3 screen last column).

3. Item 1 and 2 checks ok but no BITI:

If yellow led is steady and 1 and 2 checks out ok but you do not have BITI back, part of the signal reporting from ATHC3 to CNC is bad.

First try to download station constants. They may be bad. If all three fail you may want to replace card with one of a working station. Make sure you change station address switch when you do this. If other card works, you will have to order new card. When you send bad card make sure you write down in detail why you had to change card. This helps finding design problems and makes it faster to repair board.

1. Station does not go up or down:
   
1. Station w/o limit switch must be jumped. Otherwise, station will not work at all. Station with limit switch may be crashed. With a crash condition, you can always raise but not lower the station lift.
   
2. MIP not generating station up and down signal.
• You can check BITO_17 for up and BITO_33 for down. These BITOs are for station 1. For station 2, they will be 18 and 34 and so on.
• If you see a wrong BITO or no BITO at all, you may have an incorrect MIP.
• Check that the CNC is generating the correct KF with shift + F3 screen (MAKROS.DEF file). This so that you have more info to call back with. There is a file available listing all MIP signals, AF and KF for more detailed information.
• If all is correct, you may have problem with servo card. First check LED on THC-3 for up and down. Two LEDs, green and red, indicate which direction motor is moving. If you see an LED illuminating, control circuit of THC3 is good.
• Now disconnect motor lead and check voltage when you press up or down button.
• If you see voltage, reconnect motor lead and check voltage again while moving up or down.
• If you do not see any voltage now you may have short in motor lead or motor winding may be shorted. THC3 has internal current fold back circuit so it will try to decrease voltage as current rises beyond 6 AMP. Resultant action will be to zero out output voltage in case of direct short.
• Sometimes a short occurs while motor has current resulting in a blown output bridge mosfet.

Important: Find and correct the cause before replacing a blown board, otherwise you’ll likely just blow another one. Electronics are designed to work with nominal motor conditions. There is no chance of a servo card going bad when nothing is wrong with a motor or wiring.

• A bad motor brush is another contributor for servo failure. An intermittent connection on a brush produces transient on output mosfet bridge causing them to stress and eventual fail. Brushes must be cleaned as part of regular maintenance.
  
3. Height control does not work properly:

   This discussion applies to both capacitance and arc volt height control.

   • First thing to check is wiring.
   • If wiring is correct, then check feedback voltage returning from power supply or capacitive height control box. It is very easy to check feedback voltage from the AHC. Place multimeter on HF output and manually lower slide to plate. Voltage should gradually change from 5.0 VDC to eventually near zero at the point the probe is almost touching plate. If you did not tune board on the correct side of the curve, you will see voltage dropping, but as you approach the plate, voltage will rise again.
   • If voltage is changing properly, set height from CNC to all the way up.
   • If you turn AHC on, slide should go up.
   • Now lower standoff from CNC to lower value and slide should start coming down.
   • If it does not follow, check for BITO 63 on, with BITO 61 and 62 off. BITO 61 and 62 are multiplex signals for sensor select. Other BITOs must be on. BITO 1, station on, (for station 1) and process bito_89.
   • If there is problem, call software department.
   • Checking arc volt AHC is not as easy. Most of our machines have –15vdc available. If not you can tap it from ATHC3 card.
   • Connect potentiometer between –15 and ground.
   • Connect middle leg to x4-1.
   • Connect GRND to x4-2 (x4 located on ATHC3 card).
   • Set pot to output app. –6vdc to pin x4-1.
   • Now turn AHC on with arc voltage set to 200v.
   • Slide should go up.
   • Lower set voltage slowly until slide starts going down.
   • Change set voltage until slide stops. You should be able to make slide go up and down by either changing pot or set voltage from CNC.
   • If this does not work, check BITO 61=0, BITO 62=1, station BITO (BITO1 for station 1), BITO 63=1 and BITO 89=1 (if you are using process 6 with second type plasma this will be BITO 93). If this is not correct call software department.
     
4. Analog output for plasma or gas does not work:
   
   • Check voltage output at card connector x32, x33, x34 and x35. Check schematic for wiring.
   • In order for output to work, you must have station BITO and process BITO on.
   • In addition, release signal must be on to make changes to values. Refer to "Description of cutting package" for release signal description. It is defined in def.tec with S2064 (means you are using BITO 64 for release signal). S0374 (means user_374 is released signal). You can check this signal status in shift + F2 screen.
   • Also, station #29=04 to enable analog output card.
   • Refer to schematic instruction when using X32 and X33 as open loop output.
   • When you see approx. 10 VDC for all set values, this is an indication that you are missing jumper from x32 to x30 and x33 to x31.
   • A long power supply cable may result in a high current analog output. This will require shielding and isolation.
   • In addition, MIP must refresh channel every 16 msec. Some old SF1 had this problem. Check with software department for MIP change.
     
5. Output is not turning on:
   
• Loose wiring is usually the cause so check first.
• If wiring checks ok, trace schematic to find output location on the card.
• Check either relay contact or 120 VAC output (there are two cards, 120 VAC traic output and relay closing).
• If output does not come on, check BITO on shift+F2 screen.
• If correct BITO is coming on, check station constant for that output.
• If station constant is correct, you may have either bad output card or bad contact or relay.

 

a.  Setup manual up and down:

• Ensure limit switches up, down and slow down are working. Upper limit switch can be verified in SHIFT + F2 screen BITI_129 (for station #1).
• Lower limit switch can be verified in SHIFT + F3 screen in B column (last column).
• Slow down switch is biti_80 (for station #1). Moving the slide to check switches is not necessary. Touch a metal object to the switch to check operation. Most proximity switches have a LED to verify operation.
• If LED is working and signal at CNC is not, check wiring.
• Once all switches are working, bring power to GME amplifier.
• The GME amp must be disabled at this time since brake relay also controls enable signal to GME.
• Try to move slide up and down.
• If slide runs away reverse tach lead.
• If slide moves in the opposite direction but does not run away reverse both tach and motor lead.

For moving manually up and down following station constants have effect:

• Make touch using F3 with initial encoder height setting of 0.375 inch.
  
• After making touch, measure distance between plate and torch end.
  
• Adjust torch to correct height of 0.375 inch. It is good idea to force station up bito_17(for station #1) to zero. This way when adjusting torch, if torch crashes, it will not drive the station up.
  
• Now lower the sensor and make sure that top of sensor does not touch end of torch. If more clearance is needed, adjust station constant for nozzle distance to higher value.

When the encoder is selected, the standoff is given by:

[Data of Channel 30] * SCALE + Distance_Nozzle_PlateSwitch

with

SCALE a scaling factor defining the number of encoder pulses per movement. This is entered as a 16 bit word in STATxx.KON #51 (low byte) and #52 (high byte)

Distance_Nozzle_PlateSwitch

The height at which the nozzle rests, when the plate switch touches the plate. This is entered as a 16 bit word in STATxx.KON #49 (low byte) and #50 (high byte)

• By changing #49, small corrections can be made. For large correction, change high byte #50.
  
• Once correct torch height is adjusted at 0.375 inch.
  
• Make another touch with initial height value of 0.060 and fine tune torch height to get 0.060.
  
• Physical height of a torch can be changed in torch holder or by changing station constant #49 and #50.
  
• Once you get correct height at 0.060 (lower value) and 0.375 (higher value) you can verify torch height at another distance.
  
• Once you get initial height, correct pierce height and cutting encoder height will be correct.
  
• When making initial height touch, preflow timer must be set higher than 0.75 seconds. This timer is used to lower torch to plate after finding plate.
  
• Short sequence will be as follows for making touch by MIP.

• check to see if slide is initialized. After powering up, driving station up will initialize encoder card so upper limit switch must be functional.
  
• If station is ready and on the slow down switch, drive slide up to make room for probe
  
• If off the slow down switch, set bito_60. Station will turn on output for probe solenoid and wait for time set by station constant #19. After time delay, slide will start going down at a fast speed until reached to slow down switch. At this point it will approach plate at slow speed with probe down. When sensor touches plate, it will stop and store encoder position to make it zero point reference as top of plate surface.
  
• After recording (after 8 msec) it will rise up for probe up time to clear plate
  
• After probe up time, station will lift probe up by turning off probe solenoid output off.
  
• After output is off it will wait for station constant #19 delay and send AF 255 to CNC. One can check AF 255 in SHIFT + F3 screen.

Common problems and causes during touch:

1. Probe comes down and after short time it goes backup. No slide movement.

This indicates that sensor is always staying on. Check voltage output of sensor. Due to pull-up resistor it should always be 15-18vdc. When sensor is pushed in or finds electrical contact it should go to 1 VDC or less. Another common problem is metal chip or slag is causing sensor body to make contact with metal bracket (which is at ground potential). Also when sensor is screwed in too far in the sensor body.

2. It makes touch but torch is too high

This indicates not enough time for torch to get down to plate. This is result of too small pre-flow timer. Make sure it is set to value higher than 0.75 seconds.

3. Makes touch too hard

This indicates wrong setting of slow down switch. Follow direction listed early in this document to set it correctly.

4. When adjusting torch to get correct height, top of sensor hits torch with probe in down position.

This indicates that value of station constant #49 and #50 is too low. Increase value and reset torch height.

 

Torch Automatic height control: Sequence is as follows when using auto cycle start (M65 or F6):

• Makes touch but leaves bito_63 on after finding plate
• Start plasma and wait for arc on
• Once arc is on, goes to encoder pierce height
• When pierce timer is over, starts moving machine and goes to encoder cutting height
• Wait for AHC delay time
• If M57 was programmed before M65, leaves torch at encoder cutting height. This is very useful for small circle cutting
• If M57 was not programmed before M65, turns on voltage height control. Torch uses actual arc voltage to maintain height over plate surface
• During cutting, if received M57, torch height will be locked in present position
• If M58 is received after M57, torch will go back to auto voltage height control.

Common Problem with Auto Height control:

• Actual voltage is not same as command arc voltage: Adjust voltage divider in power supply to get it correct.
• Torch rises after it starts cutting and keeps going up: You are missing voltage feedback from voltage divider. Check wiring and correct problem.
• Torch moves up and down during cutting: If up down frequency is very low, integral gain is too low. Raise station constant #11. If frequency is high, position gain is too high. Lower station constant #04.

Torch does not follow plate accurately: Position gain constant 304 too low. Raise it to higher value. Typical value for ATHC-3 is 12-15.