EM1000 Troubleshooting Hints 8/2/2000 1. If you are not using the latest firmware, then upgrade to the latest. The software is available on the Z-World web site. You can determine your current software in the EM1000 by typing "Version" at the -> prompt. The EM1000 firmware can be easily updated by downloading the new software via the COM2 port. Refer to the user manual for more instructions. 2. A "continuous" flow of data from the serial device into the EM1000 will not appear at the other end of the link as a continuous flow, especially on a heavily loaded bus. This is due to the way data is packetized for transmission over Ethernet. 3. When using Hyperterm, if you change the baud rate or any other settings, be sure to SAVE the settings, then EXIT Hyperterm, and then start it up again using the new settings. Otherwise you may send data at the wrong baud rate to the EM1000 and lock up the unit. 4. The easiest "packetization" scheme to understand is the model where the serial device sends a packet of X characters, followed by a time delay. To use this mechanism, be sure that the BUFFERLENGTH is set higher than the length of the packet your device is sending, and then be sure that your serial device has a timing gap greater than the value in BUFFERTIMEOUT (where 1 = 0-55ms, 2 = 55-110ms, etc.) 5. Use HARDWARE FLOW CONTROL if your serial device supports it. Activating hardware flow control allows the EM1000 to temporarily halt data flow from the RS232 device (perhaps because the EM1000 has not been able to establish a link to the remote device, or because of heavy Ethernet traffic. Because Ethernet networks can be heavily loaded, this means that data that your serial devices sends through the EM1000 may not get to the other end immediately. If your serial device continues to send data to the EM1000 even though the last packet has not been sent yet from the EM1000 over Ethernet, then it may overflow the serial receive buffer, and you will lose data, or perhaps cause a lockup. The serial RS232 buffer is 512 bytes long. In addition to the hardware signals being hooked up, to use flow control you also need to set RTSMODE=FLOW in the DEN.EM file. 6. If you are NOT using hardware flow control, then make sure you don't send so much data, or send data so fast that you overflow the COM1 receive input buffer. Failure to do this will result in lost characters, and possibly lock up. If you still encounter problems, try dropping the baud rates of both the attached device and the EM1000. 7. If you are NOT using flow control, be sure that the CTS is tied to RTS (both on the EM1000 COM1 port), and be sure that DTR is tied to both DSR and DCD (all three signals on the EM1000 COM1 port). Failure to do so may result in EM1000 lockup over some period of time. If you suspect that this is happening, you can put the console port or the Telnet port into SPY mode. If you see a bunch of M## characters intermixed with the data, or after the data has stopped, then you may have crosstalk, or a short circuit between connector pins, or a misconnected wire. Depending on the type of flow control you are using 8. If you are using flow control, be sure that you do not accidentally have RTS or DTR (both are outputs) on the EM1000 tied to an RS232 output on the attached device. Be sure that you do not have CTS, DSR, or DCD (all inputs) tield to an RS232 input on the attached device. Failure to do so will probably result in EM1000 lock up when the attached device is power cycled. 9. If you cannot use flow control, then consider having an end-to-end acknowledgement of some sort. Your serial device would send a packet of information to the EM1000, followed by a time gap. When BUFFERTIME expires, the EM1000 tries to send the data. When the data eventually reaches the other end ("eventually", because ethernet timing is somewhat unpredictable), then the receiving device sends a short message back to the transmitting serial device saying that it got the last packet, and it's OK to for the serial device to send the next packet. 10. If you cannot use flow control or have end to end acknowlegements, and you have a heavily loaded Ethernet network, then you may need to lower the baud rates, and/or increase the dead time between your serial device transmissions. 11. Make sure the baud rates, parity, and stop bit settings of the attached device, and the EM1000 are the same. Failure to do so will result in short term lockup of the unit. 12. Do NOT use twisted pair cable to connect the RS232 signals to the EM1000. This leads to crosstalk, and to possible lockups. The Ethernet category 5 cable is twisted pair, but the RS232 cable MUST NOT BE TWISTED PAIR. 13. If the unit locks up, try resetting the unit by telnetting to it, and "reassigning" it the same address it already has. If this doesn't work, you may need to reset the unit manually. 14. If your unit locks up occasionally, try tweaking the baud rates. e.g. if your attached device is set to 9600, then try BAUD=9605, or BAUD=9595 and see if this fixes the problem. This should be a last resort. 15. When not using BUFFERTIMEOUT (e.g. BUFFERTIMEOUT=0), or if BUFFERTIMEOUT is a large value, and you are using BUFFERLENGTH to initiate packetization and sending of the data, be aware that the EM1000 may "end up" with some data stored in it's internal buffer, waiting for additional data to come into its serial port (or waiting for the long timeout to occur). The data is not LOST, it is just in the EM1000 buffer waiting for a trigger to send it. 16. If you occasionally get lockups, and none of the above remedies works, try to correlate the lockup with another event. For example, if the Ethernet cable is routed near an arc welder, which is only used on occasion, this may cause difficulties, on occasion. Or perhaps the power supply to the EM1000 is shared with another device, and when that device glitches, it transmits the glitch to the EM1000. 17. GROUND THE EM1000 ENCLOSURE to a reliable earth ground. This will prevent noise from nearby devices from radiating into the EM1000, and potentially causing problems. 18. When you are done debugging, done, turn off spy mode, and also verbose mode if you are not using the responses in an automated system. Note that there are 3 spy settings, and 3 verbose settings, one each for the COM1 port, COM2 port, and Telnet port. The settings for each port can only be changed FROM THAT PORT. REFER TO THE USER MANUAL, AND THE FAQ DOCUMENT FOR MORE OPERATIONAL DETAILS.