However, millivolt applications often use strain gage bridges. A resistive voltage divider using fixed resistors is recommended for this application. The maximum current drawn by the module is shown in the table below. To use it, find the backplane current draw and operating voltage for both modules being used in the chassis. Terminal Block Removal To remove the terminal block: 1. Loosen the two terminal block release screws. To avoid cracking the terminal block, alternate between screws as you remove them.
Drain Wire Signal Wires 1. Connect the signal wires of each channel to the terminal block. Avoid cutting leads too short.
The module ID code for the NT8 module is The module ID automatically assigns the correct number of input and output words. Input image words are multiplexed since each channel has one data word and one status word.
Page Channel Cut-Off Frequencyc Considerations Before Using Your Module The following table shows the available filter frequencies, cut-off frequency, step response, and a DC effective resolution for each filter frequency. Page Update Time Considerations Before Using Your Module Update Time The thermocouple module update time is defined as the time required for the module to sample and convert the input signals of all enabled input channels and make the resulting data values available to the SLC processor.
Page Update Time Calculation Example Considerations Before Using Your Module Update Time Calculation Example The following example shows how to calculate the module update time for the given configuration: Channel 0 configured for Hz filter frequency, enabled Channel 1 configured for Hz filter frequency, enabled Channel 2 configured for 50 Hz filter frequency, enabled Channel 3 through 7 disabled Using the values from the table on page , add the sum of all For example, if some channels are acquired at Hz and some are acquired at 50 Hz, then the total auto-calibration time would be: Frequency Auto-Calibration Words 0 to 7 correspond to module channels 0 to 7.
Page 43 Channel Configuration, Data, and Status 5. If the channel is configured for thermocouple inputs, determine if the channel data word should read in degrees Fahrenheit or degrees Celsius and enter a one or a zero in bit 9 of the configuration word.
The thermocouple module only scans enabled channels. To optimize module operation and minimize throughput times, unused channels should be disabled by setting the channel enable bit to zero default value. When set 1 the channel enable bit is used by the module to read the configuration word information selected. The first six options represent real Engineering Units displayed by the NT8 and do not require explanation. Page 48 1 When millivolts are selected, the temperature setting is ignored.
Software treats it as an over range error. This is a very small input range and, when it is scaled to PID or proportional counts ranges, a small input change results in many counts being changed. Page Select Temperature Units Bit 9 Channel Configuration, Data, and Status For example, if channel one is configured as a thermocouple type when the CJC breaks in an open-circuit condition, if open-circuit detection is disabled, the data word remains unchanged.
If the circuit selection is set at minimum, the data word is set to the low scale value for the range and format. Page Channel Status Checking Channel Configuration, Data, and Status Channel Status Checking You can use the information provided in the status word to determine if the input configuration data for any channel is valid per your configuration in O:e. The channel status can be analyzed bit by bit.
This field reflects the data type selected in bits 5 and 6 of the channel configuration word. An over-range condition exists when the input value is equal to or above the specified upper limit of the particular sensor connected to that channel. Page 57 Chapter Programming Examples Earlier chapters explained how the configuration word defines the way a channel operates.
This chapter shows the programming required to configure the module. It also provides you with segments of ladder logic specific to unique situations that might apply to your programming requirements. During the first program scan, the configuration data in N through N will be sent to the NT8 channel configuration words. Also, the ladder program should use the thermocouple temperature data location N for thermocouple temperature readings and data location N for CJC temperature readings.
Page 60 Programming Examples During the first pass, send the channel configuration data to the thermocouple module. The signal conversion method for the NT8 SLC analogue input module is Delta-sigma; this unit contains a digital low pass filter with program filter frequencies. It also contains 9 green LED lights to indicate to the user a change in the channel or module status. There are two cold-junction compensation sensors that have an accuracy of positive or negative 1.
The normal rejection frequency for the NT8 module when between the inputs is more than dB at 50 to 60 Hertz, as is its common frequency rejection mode between ground and inputs. Free Ground delivery available on all orders. Continue Shopping View Your Cart. Go To Cart Close. The products listed on this website may vary as to their country of origin; the accessories, and other items included with the product; and the language used on the packaging, the parts, and any related instructions or printed material related to the products.
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Electrostatic discharge can damage semiconductor devices inside this module if you touch backplane connector pins. Guard against electrostatic damage by observing the following precautions. Do not touch backplane connector pins. The maximum current drawn by the module is shown in the table below.
When you are using a modular system configuration, add the values shown in the table above to the requirements of all other modules in the SLC chassis to prevent overloading the chassis power supply. Place your NI8 module in any slot of an SLC modular, or modular expansion chassis, except for the extreme left slot slot 0 in the first chassis.
This slot is reserved for the processor or adapter modules.
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