Delta Tau PMAC2A-PC/104 - Manual (Page 13)

PMAC2A PC104 Hardware Reference Manual
Baseboard Hardware Setup 7
If this socketed resistor is configured as a pull-up resistor (by reversing the SIP pack in the socket), the
two parallel 2.2 k
Ω resistors act as a single 1.1 kΩ pull-up resistor, holding the line at +5V in the absence
of an external signal. This configuration is required if complementary open-collector drivers are used; it
is permissible for differential line-driver inputs.
If Pin 1 of the resistor pack, marked by a dot on the pack, matches Pin 1 of the socket, labeled by a white
square, then the pack is configured as a bank of pull-down resistors. If the pack is reversed in the socket,
it is configured as a bank of pull-up resistors.
The following table lists the pull-up/pull-down resistor pack for each input device:
Device Resistor Pack Pack Size
Encoder 1 RP30 6-pin
Encoder 2 RP31 6-pin
Encoder 3 RP36 6-pin
Encoder 4 RP37 6-pin