WEB-TC

Specifications

Document Revision 1.1, February, 2010
© Copyright 2010, Measurement Computing Corporation

Specifications
Typical for 25 °C unless otherwise specified.
Specifications in italic text are guaranteed by design.

Analog input
Table 1. Generic analog input specifications
Parameter

Conditions

Specification

Thermocouple

Four dual 24-bit, Sigma-Delta type
8 differential
500 VDC minimum between field wiring andpower supply input.
Software programmable to match sensor type±0.080 V

A/D converters
Number of channels
Input isolation
Channel configuration
Differential input voltage
range
Absolute maximum input
voltage±C0x through ±C7x relative toAGND (pins 9, 19, 28, 38)

Input impedance
Input leakage current
Common mode rejection ratio
ADC Resolution
ADC No missing codes
Input couplingWarm-up time
Open thermocouple detect
CJC sensor accuracy

Open thermocouple detect disabledOpen thermocouple detect enabled
fIN = 60 Hz

15 °C to 35 °C
0 °C to 55 °C±25 V (power on)±40 V (power off)
5 Gigohm (power on)
1 Mohm (power off)
30 nA max.
105 nA max.
100 dB min.
24 bits
24 bits
DC30 minutes min.
The maximum open detection time is 3 seconds.
-0.75 °C to 0.5 °C max.
-1.5 °C to 1.25 °C max.

Channel configurations
Table 2. Channel configuration specifications
Sensor Category

Conditions

Specification

Thermocouple

J, K, S, R, B, E, T, or N

8 differential channels

Note 1: Channel configuration information is stored on a EEPROM external to the isolated microcontroller by

the firmware whenever any item is modified. Modification is performed by commands issued over
Ethernet from an external application, and the configuration is made non-volatile through the use of theEEPROM.
Note 2: The factory default configuration is Type J.

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WEB-TC

Specifications

Compatible thermocouples
Table 3. Compatible sensor type specifications
ParameterConditions

Thermocouple

J: -210 °C to 1200 °C
K: -270 °C to 1372 °C
R: -50 °C to 1768 °C
S: -50 °C to 1768 °C
T: -270 °C to 400 °C
N: -270 °C to 1300 °C
E: -270 °C to 1000 °C
B: 0 °C to 1820 °CAccuracy
Thermocouple measurement accuracy
Table 4. Thermocouple accuracy specifications, including CJC measurement error. All specifications are (±).
SensorType

Sensor temperature

Accuracy error
maximum (°C)

Accuracy error typical (°C)

Tempco (°C/°C)

J-210 °C
0 °C
1200 °C-210 °C
0 °C
1372 °C-50 °C
250 °C
1768 °C-50 °C
250 °C
1768 °C
250 °C
700 °C
1820 °C-200 °C
0 °C
1000 °C-200 °C
0 °C
400 °C-200 °C
0 °C
1300 °C

3.098
1.282
1.178
3.318
1.292
1.495
1.892
0.853
0.734
2.010
0.844
0.612
2.199
0.824
0.471
3.050
1.465
1.010
3.226
1.334
0.856
3.406
1.300
0.978

1.762
0.724
0.684
1.843
0.730
0.799
1.058
0.479
0.416
1.124
0.475
0.347
2.192
0.821
0.469
1.708
0.826
0.564
1.797
0.754
0.496
1.897
0.735
0.571

0.040

KS

R

B

ET

N

2

0.045

0.027

0.025

0.004

0.038

0.045

0.035

WEB-TCSpecifications

Note 3: Thermocouple measurement accuracy specifications include polynomial linearization, cold-junction

compensation and system noise. These specs are for one year, or 3000 operating hours, whichevercomes first, and for operation of the WEB-TC between 15 °C and 35 °C after 30 minute warm-up. Thetempco should be applied to the accuracy specifications for operation at an ambient temperature
outside of the 15 °C and 35 °C range. There are total of four CJC sensors, two per side of the module.
Each CJC sensor is dedicated to one of the four channel pairs. The accuracy listed above assumes thescrew terminals are at the same temperature as the CJC sensor. Errors shown do not include inherent
thermocouple error. Contact your thermocouple supplier for details on the actual thermocouple
accuracy error.
Note 4: Thermocouples must be connected to the WEB-TC such that they are floating with respect to AGND

(pins 9, 19, 28, 38, 48). The WEB-TC AGND pins are isolated from earth ground. You can connect
thermocouple sensors to voltages referenced to earth ground as long as the isolation between theAGND pins and earth ground is maintained.
Note 5: When thermocouples are attached to conductive surfaces, the voltage differential between multiple

thermocouples must remain within ±1.4 V. For best results, we recommend using insulated or
ungrounded thermocouples when possible.

Throughput rate
Table 5. Throughput rate specifications
Number of Input Channels

Maximum Throughput

12345
67
82 Samples/second
2 S/s on each channel, 4 S/s total
2 S/s on each channel, 6 S/s total
2 S/s on each channel, 8 S/s total
2 S/s on each channel, 10 S/s total
2 S/s on each channel, 12 S/s total
2 S/s on each channel, 14 S/s total
2 S/s on each channel, 16 S/s total

Note 6: The analog inputs are configured to run continuously. Each channel is sampled twice per second. Themaximum latency between when a sample is acquired and the temperature data is provided by theEthernet unit is approximately 0.5 seconds.

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WEB-TC

Specifications

Digital input/output
Table 6. Digital input/output specifications
Digital type
Number of I/O
Configuration
Power on conditions
Pull-up/pull-down configuration

Digital I/O transfer rate
(software paced)
Input high voltage (+5 V mode)
Input high voltage (+3.3 V mode)
Input low voltage (+5 V mode)
Input low voltage (+3.3 V mode)
Output low voltage (IOL = 2.5 mA)
Output high voltage (IOH=-2.5mA)

CMOS
8 (DIO0 through DIO7)
Independently configured for input or output.
Switch selectable output voltages: +5 V and +3.3 V
Power on reset is Input mode except when bits are configured to operate as alarms.
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 userconfigurable 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 input – 50 port reads or single bit reads per second typical.
 Digital output – 100 port writes or single bit writes per second typical.
4 V min, 5.5 V absolute max.
2.64 V min, 5.5 V absolute max.
1 V max., -0.3 V absolute min.
0.66 V max., -0.3 V absolute min.
0.6 V max.
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
Alarm functionality

Alarm input modes

Alarm output modes

Alarm update rate

8 (one per digital I/O line)
Each alarm controls its associated digital I/O line as an alarm output. The input toeach alarm may be any of the analog temperature input channels. When an alarm isenabled, 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 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 condition ismet)
 Enabled, active low output (digital I/O line goes low when alarm condition ismet)
1 second

MemoryTable 8. Memory specifications
EEPROM
FLASH

512 bytes for sensor configuration
2 MB for device configuration and website storage

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WEB-TC

Specifications

Microcontroller
Table 9. Microcontroller specifications
Type

One high-performance 8-bit RISC microcontroller (isolated)
One high-performance 16-bit RISC microcontroller (non-isolated)

Power
Table 10. Power specifications
ParameterConditions

Specification

Supply current (Note 9)External power input (Note 8)

Continuous mode

External power supply (included)
Voltage supervisor limits

MCC p/n PS-5V2AEPS
4.75 V > Vext or Vext > 5.25 V
4.75 V < Vext < 5.25 VAvailable at +5V screw terminal
Available at +5V screw terminal

440 mA max.
+5 VDC ± 5%(+5 VDC power supply provided)+5 VDC, 10W, 5% regulationPWR LED = Off; (power fault)
PWR LED = On
4.65 V min., 5.25 V max.
10 mA max

User output voltage range
User output current available

Note 8: Voltage specification applies at barrel plug power input. The power supply provided with the board

meets this specification at the rated total power supply current. If a different power supply is used,small line resistances could cause significant voltage drop between the power supply and the barrelplug input.
Note 9: This is the total current requirement for the WEB-TC which includes up to 20 mA for the LEDs and

10 mA for the user voltage output.

Network
Ethernet compliance
Table 11. Ethernet compliance specifications
Device type
Device compatibility

IEEE 802.3 Ethernet 10Base-T
IEEE 802.3-2003 10 Mpbs Media Access Control

Ethernet connection
Table 12. Ethernet connection specifications
Ethernet typeConnector
Cable
Length
MAC address

10Base-T
RJ-45, 8 position
CAT-5 shielded, unshielded twisted pair
100 meters max.
00:12:71:Cx:xx:xx, where xxxxx is the device’s serial number5

WEB-TC

Specifications

Network factory default settings
Table 13. Factory default specifications
Factory default IP address
Factory default subnet mask
Factory default Gateway
Factory default DHCP setting
Factory default user nameFactory default password
Web Server

192.168.0.101
255.255.255.0
192.168.0.1
Enabled"webtc""mccdaq"Enabled

Network protocols
Table 14. Factory default specifications
Protocols implemented

UDP messaging protocol
TCP downloading protocol
HTTP 1.0 alternate port
Network name
Network name publication
Max number of simultaneous HTTP
connections
Max number of non-HTTP TCP
sockets

IP, ARP, ICMP, DHCP, UDP, TCP, NBNS, HTTP
Protocols using UDP or TCP for transport communicate on their IETF assigned
ports (for example HTTP on TCP port 80).
UDP port 54211
TCP port 54267
TCP port 49152-65535 (not including 54267)"webtc_xxxxx", where xxxxx is the device's serial number
via NBNS (responds to b-node broadcasts, therefore only available on the localsubnet)
35

Network security
Table 15. Factory default specifications
Security implementation
Session timeout
User-name/password encryption
Vulnerabilities

IP address based session manager with user-name/password login for
configuration and control transactions (data is not secured.)
5 minutes with no activity
Base64 (The default web page does not support encryption if Javascript isdisabled in the web browser.)
Denial of service attacks, user-name/password spoofing, script probing andsimple decryption

LED displays and the factory reset button
Table 16. LED and button configurations
POWER/COMM LED (top)

LINK/ACTTIVITY LED (bottom)
Factory reset button

4.75 V < Vext < 5.25 VOn
Vext < 4.75 V, Vext > 5.25 V Off (power fault)
Blinks during microcontroller communications.
On when there is a valid Ethernet connection and blinks when an Ethernet packet
is sent or received.
When held for 3 seconds, the POWER LED will turn off for a short time,
indicating a reset is in process. When the POWER LED turns back on, reset iscomplete and the factory default network settings have been restored.

6WEB-TC

Specifications

Environment
Table 17. Environmental specifications
Operating temperature range
Storage temperature range
Humidity

0 to 55 ° C-40 to 85 ° C
0 to 90% non-condensing

Mechanical
Table 18. Mechanical specifications
Dimensions

127 mm (L) x 88.9 mm (W) x 35.56 (H)Screw terminal connector type and pin out
Table 19. Screw terminal connector specifications
Connector type
Wire gauge range

Screw terminal
16 AWG to 30 AWG
Table 20. Screw terminal pin out

Pin1
23
45678910Signal NameRSVDNC
C0HC0L
RSVD
RSVD
C1HC1LAGND
RSVDPin Description
Reserved - see Note 10
No connect - see Note 10
CH0 sensor input (+)
CH0 sensor input (-)
Reserved - see Note 10
Reserved - see Note 10
CH1 sensor input (+)
CH1 sensor input (-)
Analog groundReserved - see Note 10Pin2728
2930
3132
33
343536Signal Name
RSVD
AGND
C7L
C7H
RSVD
RSVD
C6L
C6H
NC
RSVD

Pin Description
Reserved - see Note 10Analog groundCH7 sensor input (-)
CH7 sensor input (+)
Reserved - see Note 10
Reserved - see Note 10
CH6 sensor input (-)
CH6 sensor input (+)
No connect - see Note 10
Reserved - see Note 10

11121314151617181920212223242526

RSVD
NC
C2H
C2LRSVD
RSVD
C3H
C3LAGND
RSVD+5V
PU/D
DIO0
DIO1
DIO2
DIO3

Reserved - see Note 10
No connect - see Note 10
CH2 sensor input (+)
CH2 sensor input (-)
Reserved - see Note 10
Reserved - see Note 10
CH3 sensor input (+)
CH3 sensor input (-)
Analog groundReserved - see Note 10+5V output
Pull-up/down for digital outputs
Digital Input/Output
Digital Input/Output
Digital Input/Output
Digital Input/Output

373839404142
43444546
474849505152

RSVDAGND
C5L
C5H
RSVD
RSVD
C4L
C4H
NC
RSVDNC
GND
DIO7
DIO6
DIO5
DIO4

Reserved - see Note 10
Analog groundCH5 sensor input (-)
CH5 sensor input (+)
Reserved - see Note 10
Reserved - see Note 10
CH4 sensor input (-)
CH4 sensor input (+)
No connect - see Note 10
Reserved - see Note 10
No connect - see Note 10
Digital ground
Digital Input/Output
Digital Input/Output
Digital Input/Output
Digital Input/Output

Note 10:

Do not make connections to pins marked "NC" or "RSVD".

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WEB-TC-spec.doc