Digital Input/Output; Temperature Alarms; Memory - Measurement Computing USB-5201 User Manual

USB-5201 User's Guide
Note 6: The analog inputs are configured to run continuously. Each channel is sampled twice per second.
The maximum latency between when a sample is acquired and the temperature data is provided
by the USB unit is approximately 0.5 seconds. Throughput to CompactFlash memory card is
limited to 1 S/s per channel.

Digital input/output

Digital type
Number of I/O
Configuration
Pull up/pull-down configuration
Digital I/O transfer rate (software
paced)
Input high voltage
Input low voltage
Output low voltage (IOL = 2.5 mA)
Output high voltage (IOH = -2.5 mA)
Note 7: All ground pins on the device (pins 9, 19, 28, 38) are isolated from earth ground. If a connection
is made to earth ground when using digital I/O and conductive thermocouples, the thermocouples
are no longer isolated. In this case, thermocouples must not be connected to any conductive
surfaces that may be referenced to earth ground.

Temperature alarms

Number of alarms
Alarm functionality
Alarm input modes
Alarm output modes
Alarm update rate

Memory

EEPROM
Table 5. Digital input/output specifications
CMOS
8 (DIO0 through DIO7)
Independently configured for input or output.
Power on reset is input mode unless bit is configured for alarm.
All pins pulled up to +5 V via 47 K resistors (default). Pull down to ground
(GND) also available.
 Digital input – 50 port reads or single bit reads per second typ.
 Digital output – 100 port writes or single bit writes per second typ.
2.0 V min., 5.5 V absolute max.
0.8 V max., -0.5 V absolute min.
0.7 V max
3.8 V min.
Table 6. Temperature alarm specifications
8 (one per digital I/O line)
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 (after the device is reset) 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. Alarms will function both in
data logging mode and while attached to USB.
 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.
 Disabled, digital I/O line may be used for normal operation
 Enabled, active high output (digital I/O line goes high when alarm conditions met)
 Enabled, active low output (digital I/O line goes low when alarm conditions met)
1 second
Table 7. Memory specifications
1,024 bytes isolated micro reserved for sensor configuration
256 bytes USB micro for external application use
256 bytes USB micro reserved for data logging configuration
24
Specifications