Omega Vehicle Security OMB-NETSCAN 1500 User Manual download pdf (Page 117)

NetScan User’s Manual Calibration 6-19

Type

U2X

to verify calibration mode.

U128

should appear, indicating the unit is in calibration mode.

Enter commands similar to those in the first two columns in the following table. This example is for a

T/C card in slot #1, and a Type 3 (“T” type) thermocouple. The table on the preceding page provides

additional channel numbers to use as they apply to your system.

Enter:

J3,3,0000.0X

After each calibration enter

U2X

J6,3,0000.0X

then observe

U128

indicating no errors.

J11,3,0000.0X

J14,3,0000.0X

Note:

The number after the J is the channel number, the next number is the thermocouple “type,” and the

number preceding the X is the temperature in °C. Thus, J3,3,0000.0X means “Calibrate cold

junction offset for channel 3, type 3 (T-type) thermocouple at 0°C.

Response codes and meanings applicable to calibration are as follows:

Response to

U2X

Indication for Calibration Mode

U128

No error

U129

Read Failure (EEPROM Error)

U130

Write Failure (EEPROM Error)

U132

Chksum Err (EEPROM Error)

U136

Cal Err (offset, gain, or temperature sensor out of range)

U144

Invalid password

U160

Invalid command

Verify calibrated temperature using one of the following three options. Note related figure on

following page.

Cold Cell Method. Connect Cold Cell simulator to the T/C card’s 4 CJC reference channels and to the

DC voltage calibrator, as indicated in the following illustration, figure (a). Adjust the calibrator

voltage to match that of the desired test temperature using Voltage-to-Temperature Reference Tables.

Verify the channel readings match the test temperature for each of the four CJC reference channels.

Repeat verification for all T/C cards.

Note: The Cold Cell Simulator in figure (a) shows a special connection box attached to it. This

connection box, which can be easily made, is not part of the cold cell device.

Hot Cell Method. Connect Hot Cell simulator to T/C card’s first CJC reference channel. Adjust Hot

Cell to obtain desired test temperature and ensure temperature is stabilized. Observe channel reading

to match test temperature. Repeat test for remaining three CJC reference channels. Repeat verification

for all T/C cards.

T/C Calibrator Method (see note). Connect a thermocouple calibrator/simulator to the first

ChartScan, or NetScan, CJC channel in accordance with the calibrator/simulator manufacturer’s

instructions. Certain simulators will require the use of specific type T/C extension wire to create a

cold junction at ChartScan’s, or NetScan’s, input; while other simulators require copper wire and

reduce the output voltage as a function of ambient temperature to create the effect of a cold junction at

the main unit. Adjust the output setting to the desired temperature and verify the channel reading is

within the range of ChartScan’s, or NetScan’s, tolerance band for the T/C type and temperature.

Repeat test for remaining three CJC reference channels. Repeat this test for all thermocouple type

signal conditioning cards.

The T/C Calibrator/Simulator Method is not recommended because, unlike voltage

calibrators, T/C Calibrator/Simulators have no provisions for remote sensing (and are

therefore more readily subject to the transient effects of sampled data acquisition

systems, such as ChartScan and NetScan). These transient effects can cause erroneous

readings, even when both units are calibrated within specifications.

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Omega Vehicle Security OMB-NETSCAN 1500 User Manual Page 117

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Omega Vehicle Security OMB-NETSCAN 1500 User Manual Page 117

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