CyberResearch UCERB 24 Power limitations using multiple UCERB 24 devices, Relay configuration, Voltage drop

CyberResearch® Digital I/O UCERB 24

1.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.

2.Connect the USB OUT connector on the connected module to the USB IN connector on the new module.

3.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 Figure 3-5. Note that the last board in the chain is supplied with external power.

USB port to	POWER OUT to
USB IN
	POWER IN	CB-PWR -9V3A supply
		to POWER IN
	USB OUT	USB OUT
		to USB IN
	to USB IN
UCERB 24 power supply
to POWER IN

Figure 3-5. Daisy chain connections

Power limitations using multiple UCERB 24 devices

When daisy chaining additional CyberResearch products to the UCERB 24, you must ensure

that you provide adequate power to each board that you connect. The UCERB 24 is powered with a 9 VDC nominal, 3.0 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.

Relay configuration

You can install a pull-up or pull-down resistor at the NO and NC terminals on each relay. Note that the pull-up resistors are tied to the 5 V power and should be considered when calculating the power budget. The relay configuration is illustrated in the following schematic

			User-installed
			pull-up / pull-down resistor
				+5
			+5	GND
			GND
	Buffer/ C	NO	NC	Screw
Digital output	driver
				terminals
from the user				(3 per
	10 k			relay)
	resistor
	Pull-up/pull-down
	switch S2
	Figure 3-6. Relay configuration
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