Page 2.1
PROGRAMMABLE RESISTOR MODULES 40-290/291
pickering
SECTION 2 - TECHNICAL DESCRIPTION
SECTION 2 - TECHNICAL DESCRIPTION
FUNCTIONAL DESCRIPTION
A functional block diagram is provided in Figure 2.1. The Module is powered by a +5V input via Compact PCI
connector J1. The interface to the user test equipment is via the front panel mounted 68-pin micro-D connector, J2.
The module comprises a PCB populated with four resistor chains, thirty two single pole single throw relays (RL1
to RL32) and sixteen single pole double throw pole relays (RL33 to RL48). The relays are energised via control
signals from relay driver U8. The relay driver is addressed by PCI bridge U1 to output the required signal. Module
configuration is determined by hardwired links and data stored in EEPROM U7. PCI Bridge U1 is configured by
EEPROM U2, which also stores resistor calibration data.
Resistor chains 1 and 2 are linked via Link LK1, and resistor chains 3 and 4 are linked via Link LK3. Link 2 is not
fitted. Relays RL1 to RL36 are used to switch resistors R17 to R52, respectively, in and out of the resistor chain.
Relays RL37 to 48 are not dedicated to any function and are provided for customisation (see Figure 2.4).
