DHX DRIVER FAQ

• After installing the DHX Driver software, we suggest running the DHX Demo program to ensure the driver is configured correctly and running properly.
  


• Initially, always configure the DHX device for polled mode of operation. In this mode, a memory range is the only resource that needs to be configured. Later, you can change it to interrupt mode.
  


• If you are experiencing problems with performance, make sure both the adapter card and the driver are set up for either polled mode or interrupt mode.
  


• In polled mode, the recommended polling rate to use for optimum performance is 20 msec. The interrupt mode of operation will provide higher message rates at the expense of higher CPU load. Low-end systems (such as 486 based systems) may provide a better overall performance with adapter cards configured to run in polled mode.
  


• Make sure the adapter card’s memory address is unique and does not conflict with other cards in the system. Check for error messages in the Event Viewer. They may aid in detecting hardware conflicts.
  


• Make sure that you are communicating through the correct device.
  


• Make sure that you selected a unique station address for your device.
  

The next step is to configure a device. You’ll need to know the card’s memory address and interrupt.

The two most common errors result from either a conflict with another device or the driver configuration not matching the card configuration. Verify that the card’s memory address matches the driver’s address. Also, compare the state of the interrupt jumper/switch on the card with the polled/interrupt mode setting of the driver.

If the configurations match, there may be a conflict in the system or the card may be faulty. If possible, try a card that is known to be good in the system with the same settings. If errors still occur, try setting the card to polled mode and moving it to a new memory address (C8000, D0000, D4000, and D8000 are usually good addresses to try). Make sure you change both the driver and card settings.

Try setting the card to polled mode and moving it to a new memory address (C8000, D0000, D4000, and D8000 are usually good addresses to try). Make sure you change both the driver and card settings.

We recommend polled mode. Interrupt mode gives slightly higher performance, but it puts a greater load on the CPU. Finding free interrupts and worrying about interrupt conflicts may also be a concern. For the majority of applications, running in polled mode with a 20 msec polling interval will provide sufficient throughput. Whichever mode you choose, make sure the interrupt jumper/switch setting on the card matches the driver setting.

There are two things to check. First, make sure the card is plugged into the network. Second, it’s likely that both nodes have the same network node address. Change the card’s network station address in the Interface Adapter Card Configuration editor. You should now be able to see all of the nodes.

The DHX Demo program uses the device number to determine which card to use. The Set Device Number option lets you choose which device the demo will use. If you are using some other software, contact the manufacturer for more information on using multiple cards.

In general, only one device driver can control a physical adapter card and therefore sharing adapter cards between multiple device drivers is not allowed. However, the 5136-SD cards (ISA and PCI versions) from SST allow a dual interface operation, where a single card appears as two independent cards: the 5136-SD and the 1784-KT. The DHX Driver supports this mode of operation and allows configuring these cards to the 1784-KT Emulation mode. In this mode, the 32K dual-port memory window of the 5136-SD card is divided into two 16K windows. The DHX Driver uses the lower window while the upper window emulates the 1784-KT card and is available for other 32-bit device drivers like RSLinx.

Before the emulated 1784-KT card can be used by another driver, the DHX Driver has to be running first. To ensure that, Windows XP/2000/NT/Server 2003 provides a mechanism that allows one driver to identify another driver as its dependency. When the RSLinx Dependency check box is checked, the editor makes the following entry in the registry under the "HKLM\SYSTEM\CurrentControlSet\Services\RsiKtControl" key:

DependOnService:REG_MULTI_SZ:CLDHX

Instead of RsiKtControl, your device driver uses some other registry key name. Contact the driver manufacturer for the name of this key. If at your driver’s key location, the DependOnService value does not exist, create it (remember, it is a REG_MULTI_SZ type value). Then append the CLDHX to this multi-string.