53A-516 – Digital Input/Analog Comparator Card

• 16 independently programmable input channels
• Analog threshold and slope programmable in two ranges
• Digital input logic threshold and sense programmable
• Generates vectored priority interrupt and sets pollable latch for each channel

The sixteen inputs of the Digital Input/Analog Comparator Card can be configured under program control to function as either sixteen digital inputs or as sixteen analog comparator inputs. In either mode, each channel’s logic or threshold level is independently programmable.

Analog Comparator Mode
Each input’s voltage level is continuously monitored and it is determined if it is greater than, or less than, a threshold level programmed by the user.  When a threshold crossing is detected, a “vectored priority interrupt” is sent to the system controller. In addition, a pollable latch is set. The system controller can request the status of an individual latch or of all latches as a group.

Digital Input Mode
The logic sense (high or low true) and logic threshold level of each input channel are independently programmable. Data may be captured either upon request or when an external strobe is received. TTL outputs are provided that converts any logic level up to 200V to TTL levels. In addition, provisions are made on the card so that open collector and contract closure inputs may be monitored.

A column of five LEDs provides Built-In-Test Equipment (“BITE”) for the DI/AC Card. Two mode indicators. two status indicators, and an error indicator are included.

Specifications Analog Comparator

16 bipolar inputs.

Voltage Threshold:
Programmable by Channel,
±31.75V in 250 mV steps or ±6.35 V in 50 mV steps.

Trigger Condition:
Programmable by Channel, >or< voltage threshold.


Digital Input

16 bits.

Logic Threshold:
Programmable by Bit, ±3 1.7 5V in 250 mV steps or ±6.35V in ±50 mV steps.

Logic Sense:
Programmable by Bit high or low true.

Data Strobe (Input from Data Source):
Logic Sense, programmable high to low or low to high transition.
Logic Threshold, same as bit 16.

Data Accept (Input to Data Source) :
Logic Sense, programmable high true to low true pulse. Nominal 5 µsec wide pulse occurs when input data is returned to system controller.
Logic Levels, Output 1 TTL.
Output 2, 0.4 to 10V with 10 mA output current.
Output 3, l6V peak to peak centered about ground with 0.8 mA output current.

Data Throughput:
The rate at which data can be input continuously by the system controller is 8000 characters per second.

Common Specifications
Accuracy (Threshold or Logic Level):
±1.8% of full scale range programmed.

Input RC:
32V range, 110 KOhms shunted by 6V range, 220 KOhms shunted by

Input Protection:
±200V peak.

Interrupt Response Time:
< 1 µsec.

TTL Output Lines:
Number of Outputs, 1 For each of 16 channels.
Fan Out, 10 TTL loads.
Logic Sense, High True.
Function, Analog Comparator: true if corresponding comparator latch is set.
Digital Input true if corresponding input bit is true.

Data Format Returned to System Controller:
Digital Input Mode, four digit hexadecimal number followed by Carriage-Return/Line-Feed.  Analog Comparator Mode, single channel status. ASCII 1 or 0, or all channels whose thresholds have been crossed in a priority sequence, each number followed by Carriage-Return/Line-Feed.

Programmed By:
ASCII Characters.

Recommended cables: