PXI-2527 Overview

PXI-2527 Hardware Diagram


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Relay names are the same for every topology.

PXI-2527 Pinout


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Table 1. 1-Wire 64×1 Multiplexer Signal Descriptions
Signal Description
CHx Channel terminals
COM0+ Routing destination for all channel terminals
COM0- Routing destination for the 1WREF0 lead
Table 2. 1-Wire Dual 32×1 Multiplexer Signal Descriptions
Signal Description
CH0 through CH31 Channel terminals that route to COM0+
CH 32 through CH63 Channel terminals that route to COM1+
COM0+ Routing destination for CH0 through CH31
COM1+ Routing destination for CH32 through CH63
COM0- Routing destination for the 1WREF0 lead
COM1- Routing destination for the 1WREF1 lead
Table 3. 2-Wire 32×1 Multiplexer Signal Descriptions
Signal Description
CH0+ through CH31+ Channel terminals that route to COM0+
CH0- through CH31- Channel terminals that route to COM0-
COM0+ Routing destination for all positive channels
COM0- Routing destination for all negative channels
Table 4. 2-Wire Dual 16×1 Multiplexer Signal Descriptions
Signal Description
CH0+ through CH15+ Channel terminals that route to COM0+
CH0- through CH15- Channel terminals that route to COM0-
CH16+ through CH31+ Channel terminals that route to COM1+
CH16- through CH31- Channel terminals that route to COM1-
COM0+ Routing destination for CH0+ through CH15+
COM0- Routing destination for CH0- through CH15-
COM1+ Routing destination for CH16+ through CH31+
COM1- Routing destination for CH16- through CH31-
Table 5. 4-Wire 16×1 Multiplexer Signal Descriptions
Signal Description
CH0A+ through CH15A+ Channel terminals that route to COM0+
CH0A- through CH15A- Channel terminals that route to COM0-
CH0B+ through CH15B+ Channel terminals that route to COM1+
CH0B- through CH15B- Channel terminals that route to COM1-
COM0+ Routing destination for all positive channels (A and B)
COM0- Routing destination for all negative channels (A and B)
Table 6. Independent Topology Signal Descriptions
Signal Description
CHx Channel terminals
COM0+ Routing destination for all channel terminals
COM0- Routing destination for the 1WREF0 lead

PXI-2527 Topology

The following table lists the topologies supported by the module. Each topology supports immediate operation modes.

Topology Software Name
1-wire 64x1 Multiplexer 2527/1-Wire 64x1 Mux(NISWITCH_TOPOLOGY_2527_1_WIRE_64X1_MUX)
1-wire Dual 32x1 Multiplexer 2527/1-Wire Dual 32x1 Mux(NISWITCH_TOPOLOGY_2527_1_WIRE_DUAL_32X1_MUX)
2-wire 32x1 Multiplexer 2527/2-Wire 32x1 Mux(NISWITCH_TOPOLOGY_2527_2_WIRE_32X1_MUX)
1-wire Dual 16x1 Multiplexer 2527/2-Wire Dual 16x1 Mux(NISWITCH_TOPOLOGY_2527_2_WIRE_DUAL_16X1_MUX)
4-wire 16x1 Multiplexer 2527/4-Wire 16x1 Mux(NISWITCH_TOPOLOGY_2527_4_WIRE_16X1_MUX)
Independent 2527/Independent(NISWITCH_TOPOLOGY_2527_INDEPENDENT)

1-Wire 64×1 Multiplexer Topology

1-Wire 64×1 Multiplexer


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Making a Connection

Both the scanning command, ch2->com0;, and the immediate operation, niSwitch Connect Channels VI or theniSwitch_Connect function with parameters ch2 and com0, result in the following connections:

  • signal connected to CH2 is routed to COM0
Table 7. Pinout
Software Name Pin Number Software Name Pin Number
ch0 A1 ch36 B3
ch1 D1 ch37 C3
ch2 A2 ch38 B4
ch3 D2 ch39 C4
ch4 A3 ch40 B5
ch5 D3 ch41 C5
ch6 A4 ch42 B6
ch7 D4 ch43 C6
ch8 A5 ch44 B7
ch9 D5 ch45 C7
ch10 A6 ch46 B8
ch11 D6 ch47 C8
ch12 A7 ch48 B10
ch13 D7 ch49 C10
ch14 A8 ch50 B11
ch15 D8 ch51 C11
ch16 A10 ch52 B12
ch17 D10 ch53 C12
ch18 A11 ch54 B13
ch19 D11 ch55 C13
ch20 A12 ch56 B14
ch21 D12 ch57 C14
ch22 A13 ch58 B15
ch23 D13 ch59 C15
ch24 A14 ch60 B16
ch25 D14 ch61 C16
ch26 A15 ch62 B17
ch27 D15 ch63 C17
ch28 A16 com0 A9
ch29 D16 — —
ch30 A17 — —
ch31 D17 — —
ch32 B1 — —
ch33 C1 — —
ch34 B2 — —
ch35 C2 — —
Table 8. Additional Pin References
Module Connector Pin Number Signal Name
B9 com0–
A18 com1+
B18 com1–
C9 1wref0
C18 1wref1
A25 cjtemp+
D25 cjtemp–
Note In the 1-wire 64×1 multiplexer topology, do not connect to A18 or B18, as they are internally connected to certain routes.

1-Wire Dual 32×1 Multiplexer Topology

1-Wire Dual 32×1 Multiplexer


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Making a Connection

Both the scanning command, ch2->com0;, and the immediate operation, niSwitch Connect Channels VI or theniSwitch_Connect function with parameters ch2 and com0, result in the following connections:

  • signal connected to CH2 is routed to COM0
Table 9. Pinout
Software Name Pin Number Software Name Pin Number
ch0 A1 ch36 A12
ch1 D1 ch37 D12
ch2 A2 ch38 A13
ch3 D2 ch39 D13
ch4 A3 ch40 A14
ch5 D3 ch41 D14
ch6 A4 ch42 A15
ch7 D4 ch43 D15
ch8 A5 ch44 A16
ch9 D5 ch45 D16
ch10 A6 ch46 A17
ch11 D6 ch47 D17
ch12 A7 ch48 B10
ch13 D7 ch49 C10
ch14 A8 ch50 B11
ch15 D8 ch51 C11
ch16 B1 ch52 B12
ch17 C1 ch53 C12
ch18 B2 ch54 B13
ch19 C2 ch55 C13
ch20 B3 ch56 B14
ch21 C3 ch57 C14
ch22 B4 ch58 B15
ch23 C4 ch59 C15
ch24 B5 ch60 B16
ch25 C5 ch61 C16
ch26 B6 ch62 B17
ch27 C6 ch63 C17
ch28 B7 com0 A9
ch29 C7 com1 A18
ch30 B8 — —
ch31 C8 — —
ch32 A10 — —
ch33 D10 — —
ch34 A11 — —
ch35 D11 — —
Table 10. Additional Pin References
Module Connector Pin Number Signal Name
B9 com0–
B18 com1+
C9 1wref0
C18 1wref1
A25 cjtemp+
D25 cjtemp-

2-Wire 32×1 Multiplexer Topology

2-Wire 32×1 Multiplexer


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Making a Connection

Both the scanning command, ch2->com0;, and the immediate operation, niSwitch Connect Channels VI or theniSwitch_Connect function with parameters ch2 and com0, result in the following connections:

  • signal connected to CH2+ is routed to COM0+
  • signal connected to CH2– is routed COM0–
Table 11. Pinout
Software Name Pin Number Software Name Pin Number
+ – + –
ch0 A1 B1 ch18 A11 B11
ch1 D1 C1 ch19 D11 C11
ch2 A2 B2 ch20 A12 B12
ch3 D2 C2 ch21 D12 C12
ch4 A3 B3 ch22 A13 B13
ch5 D3 C3 ch23 D13 C13
ch6 A4 B4 ch24 A14 B14
ch7 D4 C4 ch25 D14 C14
ch8 A5 B5 ch26 A15 B15
ch9 D5 C5 ch27 D15 C15
ch10 A6 B6 ch28 A16 B16
ch11 D6 C6 ch29 D16 C16
ch12 A7 B7 ch30 A17 B17
ch13 D7 C7 ch31 D17 C17
ch14 A8 B8 com0 A9 B9
ch15 D8 C8 cjtemp A25 D25
ch16 A10 B10 — — —
ch17 D10 C10 — — —
Table 12. Additional Pin References
Module Connector Pin Number Signal Name
A18 com1+
B18 com1–
C9 1wref0
C18 1wref1
Note In the 2-wire 32×1 multiplexer topology, do not connect to A18 or B18, as they are internally connected to certain routes.

2-Wire Dual 16×1 Multiplexer Topology

2-Wire Dual 16×1 Multiplexer


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Making a Connection

Both the scanning command, ch2->com0;, and the immediate operation, niSwitch Connect Channels VI or theniSwitch_Connect function with parameters ch2 and com0, result in the following connections:

  • signal connected to CH2+ is routed to COM0+
  • signal connected to CH2– is routed COM0–
Table 13. Pinout
Software Name Pin Number Software Name Pin Number
+ – + –
ch0 A1 B1 ch18 A11 B11
ch1 D1 C1 ch19 D11 C11
ch2 A2 B2 ch20 A12 B12
ch3 D2 C2 ch21 D12 C12
ch4 A3 B3 ch22 A13 B13
ch5 D3 C3 ch23 D13 C13
ch6 A4 B4 ch24 A14 B14
ch7 D4 C4 ch25 D14 C14
ch8 A5 B5 ch26 A15 B15
ch9 D5 C5 ch27 D15 C15
ch10 A6 B6 ch28 A16 B16
ch11 D6 C6 ch29 D16 C16
ch12 A7 B7 ch30 A17 B17
ch13 D7 C7 ch31 D17 C17
ch14 A8 B8 com0 A9 B9
ch15 D8 C8 com1 A18 B18
ch16 A10 B10 cjtemp A25 D25
ch17 D10 C10 - - -

4-Wire 16×1 Multiplexer Topology

4-Wire 16×1 Multiplexer


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Making a Connection

Both the scanning command, ch2->com0;, and the immediate operation, niSwitch Connect Channels VI or theniSwitch_Connect function with parameters ch2 and com0, result in the following connections:

  • signal connected to CH2A+ is routed to COM0A+
  • signal connected to CH2A– is routed to COM0A–
  • signal connected to CH2B+ is routed to COM0B+
  • signal connected to CH2B– is routed to COM0B–
Table 14. Pinout
Software Name Pin Number
A+ A– B+ B–
ch0 A1 B1 A10 B10
ch1 D1 C1 D10 C10
ch2 A2 B2 A11 B11
ch3 D2 C2 D11 C11
ch4 A3 B3 A12 B12
ch5 D3 C3 D12 C12
ch6 A4 B4 A13 B13
ch7 D4 C4 D13 C13
ch8 A5 B5 A14 B14
ch9 D5 C5 D14 C14
ch10 A6 B6 A15 B15
ch11 D6 C6 D15 C15
ch12 A7 B7 A16 B16
ch13 D7 C7 D16 C16
ch14 A8 B8 A17 B17
ch15 D8 C8 D17 C17
com0 A9 B9 A18 B18
cjtemp A25 D25 — —

Independent Topology

Independent


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Making a Connection

With the independent topology, you can let NI-SWITCH determine the path between two specified channels by setting the intermediate channels as reserved for routing and using the niSwitch Connect Channels VI or the niSwitch_Connect function, or you can control individual relays using the niSwitch Relay Control VI or the niSwitch_RelayControl function.

Table 15. Pinout
Software Name Pin Number Software Name Pin Number
+ – + –
ch0 A1 B1 ch17 D10 C10
ch1 D1 C1 ch18 A11 B11
ch2 A2 B2 ch19 D11 C11
ch3 D2 C2 ch20 A12 B12
ch4 A3 B3 ch21 D12 C12
ch5 D3 C3 ch22 A13 B13
ch6 A4 B4 ch23 D13 C13
ch7 D4 C4 ch24 A14 B14
ch8 A5 B5 ch25 D14 C14
ch9 D5 C5 ch26 A15 B15
ch10 A6 B6 ch27 D15 C15
ch11 D6 C6 ch28 A16 B16
ch12 A7 B7 ch29 D16 C16
ch13 D7 C7 ch30 A17 B17
ch14 A8 B8 ch31 D17 C17
ch15 D8 C8 com0 A9 B9
ch16 A10 B10 com1 A18 B18
cjtemp A25 D25 — — —
Table 16. Valid Internal Channel Names
pcom0 pcom1
1wref0 1wref1
cjtemp icom0
pcom1plus pcom1minus
icom0plus icom0minus
pcom0plus pcom0minus
com1plus com1minus

PXI-2527 Thermocouple Measurement

The module and the NI TB-2627 can measure thermocouples. When measuring thermocouples, be sure to account for error in the measurements. The total error in thermocouple measurement is the sum of the system error (determined by the thermal EMF of the module and the CJC temperature of the TB-2627) and the thermocouple error (determined by the type of thermocouple used).

Tip NI software can convert a thermocouple voltage to the thermocouple temperature. Visit ni.com/examples for example programs.

Determining the System Error

To determine the system error for the module/TB-2627, first calculate the thermal EMF error of the module using the following equation.

Equation 1:

EEMF = [(T+1 – T) / (V+1 – V)] × VEMF
where:
EEMFrepresents the thermal EMF error of the module
T is the temperature being measured, in degrees Celsius
T+1 is (T + 1 °C)
V is the voltage that corresponds to T
V+1 is the voltage that corresponds to T+1
VEMF represents the thermal EMF of the module
Note In thermocouple reference tables, T and T+1 are known values used to calculate the slope of the thermocouple Temperature vs. Voltage graph. Refer to a thermocouple reference table to determine the values of V and V+1 that correspond to T and T+1, respectively.
Note Refer to the module Specifications to determine the thermal EMF value. For optimal thermocouple measurement performance (VEMF = 2.5 µV), power down the latching relays of the module. For more information about powering down latching relays, refer to the Power Down Latching Relays After Debounce property in NI-SWITCH or the Power Down Latching Relays After Settling property in NI-DAQmx.

After you have determined the thermal EMF error using Equation 1, calculate the system error using the following equation.

Equation 2:

ES = EEMF + ECJC
where
ES represents the system error of the module/TB-2627
EEMF represents the error due to thermal EMF of the module
ECJC represents the error due to the CJC temperature sensor of the TB-2627

Example: Measuring a K-type thermocouple at 200 °C with a CJC temperature of 25 °C, the system error of the module/TB-2627 is calculated in the following example.

Assuming typical thermal EMF (2.5 µV), first calculate the error due to thermal EMF using Equation 1.
EEMF = [(201 °C – 200 °C)/(8.178 µV – 8.138 µV)] × 0.0025 µV
= 0.063 °C
Note In this example, the values of V and V+1 are found in the thermocouple reference tables of Omega Engineering’s The Temperature Handbook. Vol. 29. Stamford, CT: Omega Engineering Inc, 1995.

To determine the system error, add the error due to thermal EMF to the error due to the CJC temperature sensor using Equation 2.

ES = 0.063 °C + 0.5 °C
= 0.563 °C

Determining the Thermocouple Error

Independent of the module/TB-2627 system, thermocouple error is the greater of the following values: ± a temperature range or ± a percent of the measurement.

In the example, a standard grade K-type thermocouple is used to measure 200 °C. The Temperature Handbook lists the error for a standard grade K-type thermocouple as ±2.2 °C or ±0.75% of the measurement temperature. Because ±0.75% of 200 °C (±1.5 °C) is less than ±2.2 °C, the error of a standard grade K-type thermocouple is ±2.2 °C.

Determining the Total Error

The total error in thermocouple measurement is the sum of the system error and the thermocouple error. Use the following equation to determine the total error in thermocouple measurement.

Equation 3:

ET = ES + ETH
where
ET represents the total error in thermocouple measurement
ESrepresents the system error
ETH represents the thermocouple error

To determine the total error in thermocouple measurement in the example, add the thermocouple error to the system error using Equation 3, as illustrated in the following calculation.

ET = 0.56 °C + 2.2 °C
= 2.76 °C

Assuming typical thermal EMF, the total error in thermocouple measurement at 200 °C for the module/TB-2627 with a K-type thermocouple is ±2.76 °C.

PXI-2527 Relay Replacement

The module uses electromechanical armature relays.

Replacement Relay Part Number
AXICOM (Tyco Electronics) IM42PGR (5-1462039-7)
National Instruments (10 relays, Tyco) 782051-01

Disassemble the Module

  1. Ground yourself using a grounding strap or a ground connected to your PXI chassis.
    Note Properly grounding yourself prevents damage to your module from electrostatic discharge.
  2. Refer to the Hardware Diagram and the following table to locate the relay you want to replace.
    Note Use the numbers printed on the board to verify the revision letter of the NI 2527. (Revision B = ASSY192245B-01; Revision A = ASSY192245A-01.) Use the revision letter to determine the correct reference designator for the relay you want to replace.
    Relay NameReference Designator (Revision B)Reference Designator (Revision A)
    k0k0k33
    k1k1k35
    k2k2k30
    k3k3k38
    k4k4k34
    k5k5k29
    k6k6k25
    k7k7k24
    k8k8k21
    k9k9k20
    k10k10k17
    k11k11k31
    k12k12k16
    k13k13k37
    k14k14k36
    k15k15k26
    k16k16k13
    k17k17k22
    k18k18k6
    k19k19k18
    k20k20k14
    k21k21k11
    k22k22k8
    k23k23k12
    k24k24k9
    k25k25k7
    k26k26k5
    k27k27k10
    k28k28k1
    k29k29k3
    k30k30k4
    k31k31k2
    kbc01k32k32
    khlselect0k33k28
    kref0k34k27
    khlselect1k35k23
    kref1k36k19
    kcjtempk37k15
  3. Locate the assembly and serial number labels on the board with the relay you want to replace. White labels indicate the board was assembled using lead solder (Sn 63 Pb 37). Green labels indicate the board was assembled using lead-free solder (Sn 96.5 Ag 3.0 Cu 0.5). Lead-free assemblies have assembly numbers ending in L.

Replace the Relay

Ensure you have the following:

  • Temperature-regulated soldering iron
    • Set to 371 °C (700 °F) for lead-free solder rework
    • Set to 316 °C (600 °F) for lead solder rework
  • Solder
    • 96.5/3.0/0.5 Tin/Silver/Copper solder (flux core) for lead-free solder rework
    • 63/37 Tin/Lead solder (flux core) for lead solder rework
  • Solder wick
  • Fine pick
  • Isopropyl alcohol
  • Cotton swabs
Note NI recommends using lead-free solder for relay replacement on lead-free assemblies, and lead solder for relay replacement on lead assemblies.
Notice Do not rework lead assemblies using a lead-free work station. Lead solder from the unit could contaminate the station.
Notice If a lead-free assembly is reworked with lead solder, label the assembly to indicate this. This can prevent the same unit from being reworked later on a lead-free solder station, which could contaminate the station.

If you have a surface mount rework station, replace the relay as you would any other surface mount part. Otherwise, complete the following steps to replace the relay:

  1. Use the soldering iron and solder wick to remove as much solder from the relay pads as possible. Do not leave the soldering iron on any lead for more than 5 seconds.
    Note If it is necessary to reapply the soldering iron to the pad, allow the connection to cool completely before reapplying the soldering iron.
  2. Apply heat to the pads one at a time, and use the pick to gently pry the relay pins from the pads. Make sure that the solder is molten before prying.
    Notice Using excessive force on a soldered pad can result in lifting the PCB trace and ruining the board.
  3. Remove the relay.
  4. Clean the pads with isopropyl alcohol and cotton swabs.
  5. Place the new relay on the PCB pads and solder.
  6. Remove the excess flux with isopropyl alcohol and cotton swabs.
    Notice Do not use flux remover to clean the board after relay replacement.

Reassemble the Module

Complete the Disassemble the Module steps in reverse order to reassemble your module.

Tip Use the NI-SWITCH Switch Soft Front Panel to reset the relay count after you have replaced a failed relay. Refer to the Switch Soft Front Panel Help for more information.