Measurement Computing USB-ERB08 - Manual (Page 15)

USB-ERB08 User's Guide Functional Details
External power connectors
The USB-ERB08 has two external power connectors labeled POWER IN and POWER OUT on the enclosure.
The POWER IN connector is labeled PWR IN on the board, and the POWER OUT connector is labeled PWR
OUT on the board.
Connect the POWER IN connector to the supplied +9 V external power supply. External power is required to
operate the USB-ERB08. The POWER OUT connector lets you power additional daisy chained MCC USB
Series products from a single external power supply. Depending on your load requirements, daisy chained
products may require a separate power supply. Refer to "
Power limitations using multiple USB-ERB08
devices " on page 3-4 for more information.
USB LED
The USB LED indicates the communication status of the USB-ERB08. It uses up to 5 mA of current and cannot
be disabled. explains the USB LED function. Table 3-2
Table 3-2. USB LED Illumination
USB LED
illumination Indication
Steady green The USB-ERB08 is connected to a computer or external USB hub.
Pulsing green Initial communication is established between the USB-ERB08 and the computer, or data is being
transferred.
PWR LED
The USB-ERB08 incorporates an on-board voltage supervisory circuit that monitors the external 9 V power. If
the input voltage falls outside of the specified range, the
PWR LED shuts off. explains the function of
the PWR LED.
Table 3-3
Table 3-3. PWR LED Illumination
PWR LED
illumination Indication
Steady green External power is supplied to the USB-ERB08.
Off Power is not supplied by the external supply, or a power fault has occurred. A power fault occurs
when the input power falls outside of the specified voltage range of the external supply (6.0 V to
12.5 V).
Invert/Non-invert switch (S1)
The Invert/non-invert switch (S1) sets the relay control logic per relay bank to either inverted or non-inverted.
By default, switch S1 is configured for non-invert (see
). Figure 2-3
NON-INVERT INVERT
CH
CL
S1
Figure 3-2. Switch S1 default configuration
The switch labeled CL configures relays 1 through 4, the switch labeled CH configures relays 5 through 8.
ƒ NON-INVERT : when "0" is written or read back via the USB bus, the relays are not energized.
ƒ INVERT : when "0" is written or read back via the USB bus, the relays are energized.
Switch settings do not affect the power-on condition. Use InstaCal to read the current logic setting for each
module group.
3-2