National Instruments SCXI-1321 manual

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SCXI-1321 T erminal Block Installation Guide 2 ni.com italic Italic text denotes variables, emphasis, a cross reference, or an int roduction to a key concept. This font also denote s te xt that is a placeholder for a word or v alue that you must supply . monospace T ext in this font denotes text or ch aracters that you should enter from the keyboar[...]

© National Instruments Cor poration 3 SCXI-1321 T erminal Block Installa tion Guide Connecting the Signals Note Refer to the Read Me First: Safety and Radio-Frequency Interference document before removing equipment covers, or connecting or disconnecting any signal wires. To connect the signal to the terminal block, complete the following steps, re[...]

SCXI-1321 T erminal Block Installation Guide 4 ni.com Figure 1. SCXI-132 1 Parts Locator Diagram 1 Strain-Relief Bar 2 Strain-Relief Screws 3 Safety-Ground Lug 4 Mating Connector 5 Thumbscrew 6 Top-Cover Screws 7 Top Cover Back Vie w F ront View 2 1 3 4 5 7 6[...]

© National Instruments Cor poration 5 SCXI-1321 T erminal Block Installa tion Guide Figure 2. SCXI-1321 Circuit Parts Locator Diagram Installing the T erminal Block To connect the terminal block to the SCXI mo dule front connector, complete the follow ing steps: 1. Connect the module front connector to its connector on the terminal block. 2. Make [...]

SCXI-1321 T erminal Block Installation Guide 6 ni.com Note T o minimize the temperature gradient inside the termin al block, move the SCXI chassis aw ay from any extr eme temperature dif ferential. Specifications All specifications are typical at 25 °C unless otherwise specified . Electrical Cold-junction sensor Accuracy 1 ........... ............[...]

© National Instruments Cor poration 7 SCXI-1321 T erminal Block Installa tion Guide Environmental Operating temperature........................ .... 0 to 50 °C Storage temperature ............. ................. . –20 to 70 °C Humidity ............. .............. .............. ....... 10 to 90% RH, noncondensing Maximum altitude ............[...]

SCXI-1321 T erminal Block Installation Guide 8 ni.com Note Refer to the Declaration of Conformity (DoC) for this product fo r any additional regulatory compliance in formation. T o obtain th e DoC for this p roduct, click Declarations of Conformity Information at ni.com/hardref.nsf/ . Performed or Supported Signal Conditioning This section provides[...]

© National Instruments Cor poration 9 SCXI-1321 T erminal Block Installa tion Guide The factory default v alue of all the nulling resistors on the terminal blo ck is 39 k Ω . Note These resistors are socketed for easy re placement. These sockets best f it a 1/4 W resistor lead size. T o determ ine the nulling range, use the f ollowing formula wh[...]

SCXI-1321 T erminal Block Installation Guide 10 ni.com Assuming a strain-gauge range with a gauge factor of GF = 2 and a quarter-bridge conf iguration, this range corresponds to ±1,498 µε , as given by the strain formula for a quarter-bridge strain-gauge configuration: where Figure 3. Quarter-Bridge Nulling Circuit ε 4 V r – GF 12 V r + () --[...]

© National Instruments Cor poration 11 SCXI-1321 T erminal Bloc k Installa tion Guide Figure 4. Half-Bridge Nulling Circuit CH+ CH+ CH– EX+ EX– + – + – R 1 R 2 4.5 k Ω 4.5 k Ω R SCAL 301 k Ω R Tr i m 10 k Ω R Null 39.1 k Ω (Screw Adjusts P otentiometer) R L R L R L R 4 (gauge) EX+ CH+ CH+ CH– EX+ EX– R Tr i m SCXI-1121 SCXI-1[...]

SCXI-1321 T erminal Block Installation Guide 12 ni.com Figure 5. Full-Bridge Nulling Cir cuit Shunt Calibration Shunt calibration prov ides a method of adjusti ng for gain error to improve accuracy. The shunt-calibration circui try configuration places a shunting resistor in parallel with the resis tive element connected between EX+ and CH+ (elemen[...]

© National Instruments Cor poration 13 SCXI-1321 T erminal Bloc k Installa tion Guide z is the module slot of the SCXI-1121 w is the channel o f the module that you want to engage th e shunt and take measurements For e xample, if you want to measure th e volta ge at channel 0 with the shunt resistor enabled, use the SCXI channel string ob0 ! sc1 ![...]

SCXI-1321 T erminal Block Installation Guide 14 ni.com gauge with a gauge factor of GF = 2, V exc = 3.3 V , and R = 120 Ω prod uces the following: V change = 0.3321 mV Replacing the strained voltage by V change in the quarter-bridge strain equation produces an equ i valent 199 µε of change. Refer to the NI-DAQ User Manual for more informat ion [...]

© National Instruments Cor poration 15 SCXI-1321 T erminal Bloc k Installa tion Guide Y ou can read a temperature at the begi nning of the test and use that value with the data that follows. Using this method assumes that there are no temperature v ariations during the measurement period. If there are temperature variations, the measure m ents can[...]

321924C-01 J an03 *321924C-01* W3 Nulling circuit of Channel 2 is enabled (factory default setting) Nulling circuit of Channel 2 is disabled W4 Nulling circuit of Channel 3 is enabled (factory default setting) Nulling circuit of Channel 3 is disabled Table 4. Jumper Settings of the Nu lling Circuits (Continued) Jum p e r Pos i t i o n Description D[...]