User manual

Chapter 7 VXIplug&play for the VXI-MXI-2

System Controller

You can use the System Controller control to determine whether

the VXI-MXI-2 acts as the MXIbus System Controller. When the Auto

setting (the default setting) is active, the VXI-MXI-2 automatically can

sense from the MXIbus cable whether it should be the controller.

You can select either Yes or No to manually determine if the

VXI-MXI-2 should be the MXIbus System Controller. You must

still be certain to cable the MXIbus system appropriately when you

make either of these selections.

Bus Timeout

The MXIbus Bus Timeout (BTO) is a watchdog timer for transfers

on the MXIbus. The MXIbus BTO unit operates only when the

VXI-MXI-2 is acting as the MXIbus System Controller. The

functionality of this control is similar to that of the Bus Timeout

control described previously under the VXI Bus Settings section. The

options range from 8 µs to 128 ms, with a default value of 1 ms.

After the specified amount of time has elapsed, the BTO circuitry

terminates a MXIbus cycle if no slave has responded. The BTO

circuitry is automatically deactivated when the VXI-MXI-2 is not

acting as the MXIbus System Controller. The BTO is also disabled

when the current MXIbus cycle maps to the VXIbus through a

VXI-MXI-2.

Transfer Limit

You can use this feature to control how many data transfers the

VXI-MXI-2 will perform on the MXIbus before releasing it to another

master device that is requesting use of the bus. The default setting holds

the MXIbus for an Unlimited period of time.

The other options you can choose from are 16, 64, and 256 transfers. If

you do not want the VXI-MXI-2 to hold the MXIbus for an unlimited

period of time, you can use this control to select one of these values.