Troubleshooting Automatic 8-channel Multiplexers with Built-in Diagnostic Tools

Problem Possible solution
Multiplexer will not power ON. Check the top left hand voltage supply terminals (marked + and - 24 VDC) to determine if the the correct power is present using a volt meter.
Multiplexer will not power ON. (Part 2) If the correct power is present on the supply terminals, inspect the sides for discoloration of the plastic housing. Is the multiplexer hot or producing a strong odor? If so, the multiplexer may be damaged due to voltage spike (ie: lightning) and should be replaced.
Output status light remains illuminated constantly. Verify that the correct transmitter and receiver combination are aligned with one another. (ie: the transmitter from channel 1 is matched with the receiver from channel 1) Use the Multiplexer's built-in diagnostics to determine if there is a connection or alignment problem. The transmitter or receiver photo eye wires may be short or open. This problem may occur anywhere between the photo eye body and the multiplexer socket. Check all splices and terminal strips for incorrect connections. If the wires are not protected by conduit in any area, check the outer sheath of the cable to see if it is brittle. If any problem areas are found in the wires, cut and splice them. Solder the connection and protect it from moisture. If lengths of the wire need to be replaced, use at least .22 gauge conductors. If no problem is found in the transmitter wires, the problem may be the multiplexer connection terminals. Replace any defective parts.
Output Status LED for a channel intermittently flickers Since the problem is intermittent, it may be challenging to diagnose the problem. If the gain setting for that channel is set low, try setting it to a higher level through the programming interface or WinISM software (See operating instructions for details.) Clean the face of each photo eye with a mild non-abrasive detergent. Align the photo eyes using the multiplexer's built-in alignment tool or try the "string method" of stretching a string or wire between the photo eyes so that the string passes by the eye in parallel. If both photo eyes are parallel to the string, the alignment should be correct. Check for cracks or deep scratches in the face of the photo eye. Water intrusion through a crack could damage the photo eye circuitry.
Output Status LED for a channel intermittently flickers. (Part 2) The transmit level for that channel may be set too low for the application. Set the Transmit level for the affected channel to "High" through the programming interface or WinISM software (See operating instructions for details.) Look closely at the receiver photoeye while the problem is occuring. If the receiver is mounted in direct sunlight, this may cause intermittent false signals. Verify that terminal 3 is connected to Earth ground. If either photo eye appears damaged replace it immediately.
Output Status LED will not turn ON. The transmit level for that channel may be set too high for the application. Set the Transmit level for the affected channel to "Low" through the programming interface or WinISM software (See operating instructions for details.) Verify that terminal 3 is connected to Earth ground. If either photo eye appears damaged replace it immediately.
Output Status LED will not turn ON. (Part 2) If more than one multiplexer and sets of photo eyes are in-use in the same area, verify that there is no "crosstalk" between the systems. If other sets of photo eyes are operating on the same frequency, the receiver of one set may see light from the transmitter of another set. To correct this, Pantron 4 and 8 channel multiplexers may be connected in a Master/Slave configuration which completely eliminates crosstalk.
Multiplexer responds the opposite of its expected operation If the multiplexer outputs when it shouldn't and doesn't output when it should, the problem may be the setting of the "switching behavior." Set the switching behaviour for the affected channel to the opposite setting through the programming interface or WinISM software (See operating instructions for details.) The "switching behavior" or "Light/Dark" setting of the multiplexer controls when the multiplexer activates the output, either when the receiver sees light from the transmitter (light switching) or when it doesn't (dark switching)
Power Limit indicator LED is ON This LED is signaling that a channel has reached is power limit and the output is active. Check alignment for each channel and clean the photo eyes. Then reset the device.
Multiplexer displays low signal strength. The photo eyes are both functioning, but have limited visibility. Clean the face of each photo eye with a mild non-abrasive detergent. Align the photo eyes using percentage bar on the multiplexer have a second individual watch and report on the bar status as you align the eye. The alignment should be correct. Check for cracks or deep scratches in the face of the photo eye. Water intrusion through a crack could damage the photo eye circuitry. If either photo eye appears damaged replace it immediately.
Multiplexer diagnostics report "transmitter short" The red and black (or brown and blue for quick-connect version) wires of the transmitter photo eye that connect to the multiplexer are touching. These wires connect to IT (1-8) terminals. The shorting of the wires may occur anywhere between the photo eye body and the multiplexer. Check all splices and terminal strips for incorrect connections. If the wires are not protected by conduit in any area, check the outer sheath of the cable to see if it is brittle. If any problem areas are found in the wires, cut and splice them. Solder the connection and protect it from moisture. If lengths of the wire need to be replaced, use at least .22 gauge conductors. If no problem is found in the transmitter wires, the problem may be a loose connection on the multiplexer terminals.
Multiplexer diagnostics report "transmitter open" One or both of the red and black wires (or brown and blue for quick-connect version) of the transmitter photo eye that connect to the multiplexer are disconnected. These wires connect to IT (1-8) terminals. The interruption of the wires may occur anywhere between the photo eye body and Multiplexer. Check all splices and terminal strips for incorrect connections. If the wires are not protected by conduit in any area, check the outer sheath of the cable to see if it is brittle. If any problem areas are found in the wires, cut and splice them. Solder the connection and protect it from moisture. If lengths of the wire need to be replaced, use at least .22 gauge conductors. If no problem is found in the transmitter wires, the problem may be a loose connection on the multiplexer terminals.
Multiplexer diagnostics report "receiver short" The yellow and silver (or black and blue for quick-connect version) wires of the receiver photo eye that connect to the multiplexer are touching. These wires connect to IR (1-8) terminals. The shorting of the wires may occur anywhere between the photo eye body and the multiplexer. Check all splices and terminal strips for incorrect connections. If the wires are not protected by conduit in any area, check the outer sheath of the cable to see if it is brittle. If any problem areas are found in the wires, cut and splice them. Solder the connection and protect it from moisture. If lengths of the wire need to be replaced, use at least .22 gauge conductors. If no problem is found in the receiver wires, the problem may be a loose connection on the multiplexer terminals.
Multiplexer diagnostics report "receiver open" One or both of the yellow and silver wires (or black and blue for quick-connect version) of the receiver photo eye that connect to the multiplexer are disconnected. These wires connect to IR (1-8) terminals. The interruption of the wires may occur anywhere between the photo eye body and Multiplexer. Check all splices and terminal strips for incorrect connections. If the wires are not protected by conduit in any area, check the outer sheath of the cable to see if it is brittle. If any problem areas are found in the wires, cut and splice them. Solder the connection and protect it from moisture. If lengths of the wire need to be replaced, use at least .22 gauge conductors. If no problem is found in the receiver wires, the problem may be a loose connection on the multiplexer terminals.