Post by romaxxcnc on Jun 26, 2011 14:28:04 GMT -5
Encoder Board troubleshooting guide
Please read before continuing.
IMPORTANT: Some of the tests in this troubleshooting guide involve using electronic test equipment and performing those tests while the boards are at line voltage 120/220 VAC, which is lethal. These tests are outlined and intended for qualified service technicians only.
Brief overview of how the Closed loop system/Encoder board works:
The "Closed loop system" and associated "Rogers Encoder" plug-in for Mach3 are a means in which to monitor machine position, and halt machine motion on position loss.
The Plug-in monitors two sets of DRO's or Digital Read Outs in Mach3. The X,Y,Z position DRO's on the main Mach3 screen and X,Y,Z encoder DRO's which are on the "Settings" screen of Mach3. Comparing the two real-time during motion. There is an following error limit for each axis that can be configured in Mach3 under "Config/Config Plug-ins/Rogers encoder/Configure" The default setting for each axis is .030".
There must be an error limit entered, zero will not work, and is impossible. When an axis accelerates up to commanded speed, it lags behind the commanded position, the encoder reads the actual axis position. The only time the encoder and Mach3 are near 1:1 is at constant speeds. Thus, accelerations create an inherent difference between Commanded and Actual machine position.
The encoder plug-in is sent in a zipped folder, it must be "extracted" or the folder "unzipped". Attempt of use without extraction will corrupt the file. This goes for any files including the XML's downlaoded from our site as well.
The most common support issue we encounter with the encoder board is lack of communication with the host PC. This is generally caused by an improper driver installed for the 2nd LPT parallel port. Another common cause of no encoder display, is no Mach3 license present in the C:/Mach3 main folder. Encoder display will not work in Demo mode.
The driver from the included disc must be used. If not, windows will install it's own generic driver and it will not work for most after market parallel ports, like the Netmos 9805 chipset version that we send out. When installing the parallel port, make sure and point to the disc that came with the parallel port. This driver can also be downloaded from our website here:
romaxxcnc.com/downloads.html
After installation of the parallel port, the port address needs to be located in Windows.
It is at: Start / Control panel / System / Hardware / Device manager/ Ports. Click on the "+" next to Ports and expand it. Find the port LPT2 or LPT3, double click on it.
Click on the resources tab, in the picture below is the port address.
If this address is perhaps "0007", this is usually the port address for the Windows generic driver. It will not work. The port address is usually a combination of letters and numerals. i.e. E4F8. The address must be entered in Mach3, on the ports and pins page under second parallel port. Sending us your computer for driver installation is always an option.
If the parallel port is installed properly, and there is still no encoder display in Mach3, there are some tests that can be performed. As stated above, these should only be performed by a qualified service technician.
Pulling the board or sending us the whole electronics panel for service is always an option.
Pulling the panel, simply slide it out of the base about half-way, then disconnect the drives, the terminal strip will lift off of each. Disconnect the encoder wires, for reconnecting, take a digital camera shot for reference. Red=5v White=A channel Black= B channel Green = GND.
For these tests: Unplug the machine, push the Estop in. Disconnect the parallel port cable from the second parallel port on the computer. Leave it connected to "Port 2" on the machine.
Unplug the machine, push the Estop in.
We will work with Z axis alone, assuming there is no communication. Z axis encoder is connected to pins 8 and 9 on the encoder board. These are pins 8 and 9 respectively on the DB-25 communication cable as well.
In the pic below, the pins are called out.
Notice the orientation of the trapezoidal shield.
Plug the machine up, twist out the Estop. There should be a yellow status light. Do not clear the flashing Reset in Mach3, this will power up the drives/motors if port 1 cable is connected, and is not part of the test.
There may be a buzzing sound, this is normal, it is the relays on the encoder board floating with no signal.
Using a voltmeter set to DC volts clip the black (-) lead to pin 25 on the parallel port cable, using the pic above as reference. Connect the Red (+) lead to pin 8. Reach behind the Z plate and roll the ballscrew by hand very slow. The voltage on the meter should be fluctuating between 4.8~ volts and .2~volts. Do the same for pin 9. Should be the same voltage behavior when turning the screw slowly. This verifies there is at least encoder signal for Z axis all the way back to the PC.
If there is no fluctuation in voltage observed after performing this test, scroll down to "Encoder board Diagnosis"
It should be displaying on the "settings" screen in Mach3. Reconnect the cable to the port. The "Reset" in the lower left in Mach3 should be flashing. Do not try to clear it. Click on the settings tab at the top of the main screen. It opens the green background settings screen. In the center are the encoder DRO's. Turn the ballscrew slowly again, the numbers should be counting up and down, if they are not, there is a problem with the second parallel port. Looping back to the beginning of this doc, it is usually the driver.
Encoder board diagnosis:
Remove the 6 screws in the front panel and slide the tray out far enough only to examine the encoder board in the lower right corner.
Obvious things to check:
Ribbon cable down tight in it's plug, yellow and black wire connected on the upper left 2 terminal block (J10). All encoder wires connected.
First, let's determine there is power for the board, line voltage 110 or 220 VAC should be coming in on J10 at the upper left two terminal block. With the meter set to AC volts, ascertain there is the proper voltage.
Next, check to see if there is power to the encoders. Set the meter for DC volts.
In the picture below, the connection of the Z axis encoder is depicted. Note the labeling on the greenboard. The labeling is respective, X,Y,Z and A axis.
Put a voltmeter red lead on the 5V and the black lead on the GND. It should read 4.8~volts DC. If it doesn't, there is a problem with the board. Most likely cause is the onboard fuse, it is soldered in and right behind J10 where the main power comes in. Power the machine down and use the meter set to ohms and check the fuse for continuity. If it's blown, solder in a new one, or send the board back to us for servicing.
If there was 5VDC, procced:
Similar to the test we performed with the end of the DB-25 cable. as in the pic below put the voltmeter red lead (+) on 5V and the black lead on ZB, roll the ballscrew slowly, the meter should fluctuate between 4.8~VDC and .2~VDC.
Move the black lead over to ZA, same voltage display should be observed on turning the ballscrew slowly.
If there was only activity on one channel this is more than likely a broken wire or the encoder has become unplugged at the encoder case. If there is no signal at all, this means the encoder is unplugged at the encoder case or has simply failed.
If there was signal on ZA and ZB, we'll move further down and check. Leave the red lead attached to 5V
Disconnect the ribbon cable at the board.
In the pic below are pins 8 and 9 for Z axis. Perform the ballscrew rotation test on each of these pins.
If there is A and B signal activity on both of these pins, and not at the end of the DB-25 cable: Probable causes are cable not plugged in fully, or simply a bad communication cable.
Please read before continuing.
IMPORTANT: Some of the tests in this troubleshooting guide involve using electronic test equipment and performing those tests while the boards are at line voltage 120/220 VAC, which is lethal. These tests are outlined and intended for qualified service technicians only.
Brief overview of how the Closed loop system/Encoder board works:
The "Closed loop system" and associated "Rogers Encoder" plug-in for Mach3 are a means in which to monitor machine position, and halt machine motion on position loss.
The Plug-in monitors two sets of DRO's or Digital Read Outs in Mach3. The X,Y,Z position DRO's on the main Mach3 screen and X,Y,Z encoder DRO's which are on the "Settings" screen of Mach3. Comparing the two real-time during motion. There is an following error limit for each axis that can be configured in Mach3 under "Config/Config Plug-ins/Rogers encoder/Configure" The default setting for each axis is .030".
There must be an error limit entered, zero will not work, and is impossible. When an axis accelerates up to commanded speed, it lags behind the commanded position, the encoder reads the actual axis position. The only time the encoder and Mach3 are near 1:1 is at constant speeds. Thus, accelerations create an inherent difference between Commanded and Actual machine position.
The encoder plug-in is sent in a zipped folder, it must be "extracted" or the folder "unzipped". Attempt of use without extraction will corrupt the file. This goes for any files including the XML's downlaoded from our site as well.
The most common support issue we encounter with the encoder board is lack of communication with the host PC. This is generally caused by an improper driver installed for the 2nd LPT parallel port. Another common cause of no encoder display, is no Mach3 license present in the C:/Mach3 main folder. Encoder display will not work in Demo mode.
The driver from the included disc must be used. If not, windows will install it's own generic driver and it will not work for most after market parallel ports, like the Netmos 9805 chipset version that we send out. When installing the parallel port, make sure and point to the disc that came with the parallel port. This driver can also be downloaded from our website here:
romaxxcnc.com/downloads.html
After installation of the parallel port, the port address needs to be located in Windows.
It is at: Start / Control panel / System / Hardware / Device manager/ Ports. Click on the "+" next to Ports and expand it. Find the port LPT2 or LPT3, double click on it.
Click on the resources tab, in the picture below is the port address.
If this address is perhaps "0007", this is usually the port address for the Windows generic driver. It will not work. The port address is usually a combination of letters and numerals. i.e. E4F8. The address must be entered in Mach3, on the ports and pins page under second parallel port. Sending us your computer for driver installation is always an option.
If the parallel port is installed properly, and there is still no encoder display in Mach3, there are some tests that can be performed. As stated above, these should only be performed by a qualified service technician.
Pulling the board or sending us the whole electronics panel for service is always an option.
Pulling the panel, simply slide it out of the base about half-way, then disconnect the drives, the terminal strip will lift off of each. Disconnect the encoder wires, for reconnecting, take a digital camera shot for reference. Red=5v White=A channel Black= B channel Green = GND.
For these tests: Unplug the machine, push the Estop in. Disconnect the parallel port cable from the second parallel port on the computer. Leave it connected to "Port 2" on the machine.
Unplug the machine, push the Estop in.
We will work with Z axis alone, assuming there is no communication. Z axis encoder is connected to pins 8 and 9 on the encoder board. These are pins 8 and 9 respectively on the DB-25 communication cable as well.
In the pic below, the pins are called out.
Notice the orientation of the trapezoidal shield.
Plug the machine up, twist out the Estop. There should be a yellow status light. Do not clear the flashing Reset in Mach3, this will power up the drives/motors if port 1 cable is connected, and is not part of the test.
There may be a buzzing sound, this is normal, it is the relays on the encoder board floating with no signal.
Using a voltmeter set to DC volts clip the black (-) lead to pin 25 on the parallel port cable, using the pic above as reference. Connect the Red (+) lead to pin 8. Reach behind the Z plate and roll the ballscrew by hand very slow. The voltage on the meter should be fluctuating between 4.8~ volts and .2~volts. Do the same for pin 9. Should be the same voltage behavior when turning the screw slowly. This verifies there is at least encoder signal for Z axis all the way back to the PC.
If there is no fluctuation in voltage observed after performing this test, scroll down to "Encoder board Diagnosis"
It should be displaying on the "settings" screen in Mach3. Reconnect the cable to the port. The "Reset" in the lower left in Mach3 should be flashing. Do not try to clear it. Click on the settings tab at the top of the main screen. It opens the green background settings screen. In the center are the encoder DRO's. Turn the ballscrew slowly again, the numbers should be counting up and down, if they are not, there is a problem with the second parallel port. Looping back to the beginning of this doc, it is usually the driver.
Encoder board diagnosis:
Remove the 6 screws in the front panel and slide the tray out far enough only to examine the encoder board in the lower right corner.
Obvious things to check:
Ribbon cable down tight in it's plug, yellow and black wire connected on the upper left 2 terminal block (J10). All encoder wires connected.
First, let's determine there is power for the board, line voltage 110 or 220 VAC should be coming in on J10 at the upper left two terminal block. With the meter set to AC volts, ascertain there is the proper voltage.
Next, check to see if there is power to the encoders. Set the meter for DC volts.
In the picture below, the connection of the Z axis encoder is depicted. Note the labeling on the greenboard. The labeling is respective, X,Y,Z and A axis.
Put a voltmeter red lead on the 5V and the black lead on the GND. It should read 4.8~volts DC. If it doesn't, there is a problem with the board. Most likely cause is the onboard fuse, it is soldered in and right behind J10 where the main power comes in. Power the machine down and use the meter set to ohms and check the fuse for continuity. If it's blown, solder in a new one, or send the board back to us for servicing.
If there was 5VDC, procced:
Similar to the test we performed with the end of the DB-25 cable. as in the pic below put the voltmeter red lead (+) on 5V and the black lead on ZB, roll the ballscrew slowly, the meter should fluctuate between 4.8~VDC and .2~VDC.
Move the black lead over to ZA, same voltage display should be observed on turning the ballscrew slowly.
If there was only activity on one channel this is more than likely a broken wire or the encoder has become unplugged at the encoder case. If there is no signal at all, this means the encoder is unplugged at the encoder case or has simply failed.
If there was signal on ZA and ZB, we'll move further down and check. Leave the red lead attached to 5V
Disconnect the ribbon cable at the board.
In the pic below are pins 8 and 9 for Z axis. Perform the ballscrew rotation test on each of these pins.
If there is A and B signal activity on both of these pins, and not at the end of the DB-25 cable: Probable causes are cable not plugged in fully, or simply a bad communication cable.