Measurement Computing WEB-TC - Manual (Page 31)

WEB-TC User's Guide Specifications
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Digital input/output
Table 6. Digital input/output specifications
Digital type CMOS
Number of I/O 8 (DIO0 through DIO7)
Configuration Independently configured for input or output.
Switch selectable output voltages: +5 V and +3.3 V
Power on conditions
Power on reset is Input mode except when bits are configured to operate as
alarms.
Pull-up/pull-down configuration All pins are connected to 47 kOhm resistors that share a common point
accessible at Pin 22 of the device (PU/D). This pin is floating by default and is
user-configurable via external connection. For pull-up mode, connect this pin
to Pin 21 (+5V). For pull-down mode, connect this pin to Pin 48 (GND).
Digital I/O transfer rate (software paced)
 Digital input – 50 port reads or single bit reads per second typical.
 Digital output – 100 port writes or single bit writes per second typical.
Input high voltage (+5 V mode) 4 V min, 5.5 V absolute max.
Input high voltage (+3.3 V mode) 2.64 V min, 5.5 V absolute max.
Input low voltage (+5 V mode) 1 V max., -0.3 V absolute min.
Input low voltage (+3.3 V mode) 0.66 V max., -0.3 V absolute min.
Output low voltage (IOL = 2.5 mA) 0.6 V max.
Output high voltage (IOH=-2.5 mA) 4.3 V min. (+5 V mode), 2.7 V (+3.3 V mode)
Note 7: Ground pins on the WEB-TC labeled GND are isolated from AGND pins and from earth ground.
Temperature alarms
Table 7. Temperature alarm specifications
Number of alarms 8 (one per digital I/O line)
Alarm functionality Each alarm controls its associated digital I/O line as an alarm output. The input to each
alarm may be any of the analog temperature input channels. When an alarm is enabled, its
associated I/O line is set to output and driven to the appropriate state determined by the
alarm options and input temperature. The alarm configurations are stored in non-volatile
memory and are loaded at power on.
Alarm input modes
 Alarm when input temperature > T1
 Alarm when input temperature > T1, reset alarm when input temperature goes below T2
 Alarm when input temperature < T1
 Alarm when input temperature < T1, reset alarm when input temperature goes above T2
 Alarm when input temperature is < T1 or > T2
Note: T1 and T2 may be independently set for each alarm.
Alarm output modes
 Disabled, digital I/O line may be used for normal operation
 Enabled, active high output (digital I/O line goes high when alarm condition is met)
 Enabled, active low output (digital I/O line goes low when alarm condition is met)
Alarm update rate 1 second
Memory
Table 8. Memory specifications
EEPROM 512 bytes for sensor configuration
FLASH 2 MB for device configuration and website storage
Microcontroller
Table 9. Microcontroller specifications
Type One high-performance 8-bit RISC microcontroller (isolated)
One high-performance 16-bit RISC microcontroller (non-isolated)