Measurement Computing USB-1096HFS - Manual (Page 18)

USB-1096HFS User's Guide Functional Details
Ground terminals
The USB-1096HFS has four identical ground ( GND ) connections - one ground terminal per digital port group.
The ground terminals provide a common ground for all USB-1096HFS functions.
Counter terminal
Connect an external TTL signal to the screw terminal labeled CTR . The internal counter increments when the
TTL level transitions from low to high. The counter can count frequencies of up to 1 MHz.
Daisy chaining additional modules to the USB-1096HFS
Daisy chained MCC USB Series products connect to the USB bus through the high-speed hub on the USB-
1096HFS. You can daisy chain a maximum of four USB boards to a single USB 2.0 port or USB 1.1 port on
your computer. Use the supplied cable or an equivalent cable when daisy chaining MCC USB Series products.
Depending on your load requirements, you may need to supply external power to each MCC USB Series
product that you want to daisy chain. Refer to the next section "
Power limitations using multiple USB-1096HFS
devices " for more information.
MCC USB Series products are USB 2.0 full-speed devices that provide a signaling bit rate of 12 Mb/s. The
throughput rate is shared by all devices connected to the USB bus.
To daisy-chain two or more USB-1096HFS modules, follow the steps below. This procedure assumes you
already have one USB-1096HFS connected to a computer and to the external power source. The USB-1096HFS
already connected to the computer is referred to as the connected module. The USB-1096HFS you want to
daisy-chain to the connected module is referred to as the new module.
1.
2.
3.
Connect the USB OUT connector on the connected module to the USB IN connector on the new module.
Connect the POWER OUT connector on the connected module to the POWER IN connector on the new
module.
For each additional module you want to add, repeat steps 1-2, with the module you just daisy chained now
being the connected module.
A daisy chain system is shown in . Note that the last board in the chain is supplied with external
power.
Figure 3-4
Figure 3-4. USB-1096HFS daisy-chain connections
USB port to
USB IN
USB OUT
to USB IN
POWER OUT to
POWER IN
USB OUT
to USB IN
CB - PWR - 9V3A supply
to POWER IN
CB - PWR - 9V3A supply
to POWER IN
3-5