Led states, Daisy chaining multiple usb-ssr08 devices, Power limitations using multiple usb-ssr08 devices – Measurement Computing USB-SSR08 User Manual
Page 18: Voltage drop, Led states -4, Daisy chaining multiple usb-ssr08 devices -4, Voltage drop -4, Ge 3-4
USB-SSR08 User's Guide
Functional Details
LED states
Independent LEDs (
D1
–
D8
) at each module position indicate the on/off status of each module. The LED
illuminates when an output module is active (turned on) or when an input module detects an input voltage.
Daisy chaining multiple USB-SSR08 devices
Daisy chained MCC USB Series products connect to the USB bus through the high-speed hub on the USB-
SSR08. You can daisy chain a maximum of four MCC USB Series products 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.
To daisy chain two or more USB-SSR08 modules, follow the steps below. This procedure assumes you already
have one USB-SSR08 connected to a computer and to an external power source. The USB-SSR08 already
connected to the computer is referred to as the connected module. The USB-SSR08 you want to daisy chain to
the connected module is referred to as the new module.
1.
2.
3.
Connect the
Power OUT
connector on the connected module to the
Power IN
connector on the new
module.
This step is required only if you plan to daisy chain power to another module.
Connect the
USB OUT
connector on the connected module to the
USB IN
connector on the new module
To add another module, repeat steps 1-2, with the module you just connected now being the connected
module.
A daisy chain example is shown in
. Note that the last board in the chain is supplied with external
power.
Figure 3-6. USB-SSR08 daisy chain connections
USB port to
USB IN
USB OUT
to USB IN
USB OUT
to USB IN
POWER OUT
to POWER IN
CB-PWR-9
supply
to POWER IN
CB-PWR-9
supply
to POWER IN
Power limitations using multiple USB-SSR08 devices
When daisy chaining additional MCC USB Series products to the USB-SSR08, you must ensure that you
provide adequate power to each board that you connect. The USB-SSR08 is powered with a 9 VDC nominal,
1.0 A external power supply.
Voltage drop
A drop in voltage occurs with each board connected in a daisy chain system. The voltage drop between the
power supply input and the daisy chain output is 0.5 V maximum. Factor in this voltage drop when you
configure a daisy chain system to ensure that at least 6.0 VDC is provided to the last board in the chain.
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