Functional Description - Keithley ERB-24 User Manual

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Functional Description

Each of the 24 relays on the ERB-24 board is supported by its own
control line. The relay is an electromechanical, dual form C (double-pole,
double-throw) module capable of switching loads under program control.
The electromechanical relays offer zero-leakage output currents.
Each relay contains two normally open contacts and two normally closed
contacts. Each contact can switch up to 3 A (resistive) at 120 Vrms.
The ERB-24 provides both a 37-pin and a 50-pin connector. The 37-pin
µ
connector is provided for connecting to a PIO-12, PIO-24, CPIO-12, or
µ
CPIO-24 digital I/O board or to the 37-pin auxiliary connector on a
DAS-1600 Series or DAS-1200 Series board. The 50-pin connector is
provided for connecting to a PIO-96 digital I/O board.
A 5 V signal applied to the corresponding relay control pin on the
connector energizes the relay. Onboard transistor drivers allow control of
the ERB-24 by any LSTTL- or NMOS/ CMOS-compatible digital output
board.
The ERB-24 contains an annunciator LED for each relay for purposes of
monitoring and troubleshooting. Each annunciator LED lights when its
associated relay is energized.
The board also contains its own power supply. The power supply operates
on 115/230 VAC and accepts 15% voltage fluctuations. Operating
° °
temperatures range from 0 to 60 C.
A block diagram of the ERB-24 board is shown in Figure 2-1. Figure 2-2
shows the circuitry for a single relay channel.
2-1