Description

Model 526 measures incremental encoders pulses, analog voltages and detects digital signals. It also generates analog voltages, digital outputs and has a watchdog timer and an interrupt timer.

Encoder Counters
The four quadrature encoder inputs and index inputs may be differential (RS-422) or single-ended TTL.  Counting resolution can be increased by selecting x2 or x4 counting modes.  Each counter may be programmed to cause an interrupt when it overflows. The current value of a counter may be read without affecting the counting process.

Counters may be configured as timers by counting pulses from an internal clock of 27 or 13.5 MHz.  Timers can generate a single-shot pulse or a pulse width modulated waveform at one of the digital outputs.

Watchdog Timer
If enabled, the watchdog timer times out after a selected interval if it is not tagged.  This timer can control two external solid state relays (one normally closed and one normally open).     

Interrupt Timer
This timer provides a way of generating precise interrupts.  Two operating modes are available: manual and auto-restart. In the manual restart mode the count starts on a software command and stops when the zero count is reached. In Auto-restart mode the counter automatically reloads after the zero count is reached.

Analog Outputs
The 526 has four 16-bit D/A converters with individual preload buffers.  A single command will update all D/A’s in about 32 uS.  An interrupt can optionally be generated when the upload is complete. There are no trimpots for the 526’s D/A’s. Sensoray’s factory calibration stores calibration data in an EEPROM on the 526. Precise output voltages are obtained by using this data.

Analog Inputs
The eight differential inputs are multiplexed to a 16-bit A/D. The input range is slightly larger than ±10 volts to allow for software calibration. Multiple channels can be measured with just one command. Two reference channels (0 V and 10 V) can also be measured.

The A/D converter is factory calibrated by storing the actual value of the on-board 10 V reference in the EEPROM.

Digital I/O
The 526 has eight I/O lines for use as general purpose inputs or outputs in groups of four.  Under software control interrupts can be generated on the rising or falling edge of every signal in both groups.

DC/DC Converter
The 526 requires a power supply input of just 5 volts. Its on-board DC/DC converter generates +/- 15 volts for the analog circuits and 3.3 volts for the digital circuits.

Images and Mechanical Drawings