Setting Configuration Switches
The SCP has three packages of eight switches each. The package labeled OE (Output Enable) determines a channel’s I/O direction. The package labeled PU (pull-up) controls whether or not a channel is floating or pulled up to an internal 5V supply. The package labeled VRS (for channels 0 and 1 only) can enable special input signal conditioning compatible with variable reluctance sensors. For a discussion on using the VRS mode, see "VRS Mode Input Operation" on page 10.
Locating switches Figure 2 shows the location of each channel’s configuration switches.
Figure 2. Switch Location and Example Settings
Configuring Input- Output direction
Configuring Channel Pull-up Resistor
Refer to Figure 2 for the location of the eight Output Enable (OE) switches. Move the channel’s switch handle to the ON position for output, and to the OFF position for input.
Refer to Figure 2 for the location of the eight Pull-up Enable (PU) switches. Move the switch handle to the ON position to connect the pull-up resistor (connected from channel terminal to an internal +5V), and to the OFF position to disconnect the pull-up resistor (high impedance input/open drain output).
Note Pull-Up enable ON is not allowed for channels that have their VRS enable ON (VRS is only available on channels 0 and 1).
6 Agilent E1538A Enhanced Frequency/Totalize/PWM SCP