GE IS230TNAIH4C | Mark VIe Analog I/O TB – 16 Mixed Channels

Description

Product Introduction

The module configuration was set for voltage inputs, but the field instruments were 4-20 mA current loops. That’s a mismatch that requires a new terminal block—or a whole lot of external resistors. The IS230TNAIH4C handles both voltage and current with built-in, jumper-selectable 250 Ω burden resistors. It’s the Swiss Army knife of analog termination blocks: voltage mode, current mode, or a mix on the same block.

GE’s IS230TNAIH4C is the termination assembly for the Mark VIe configurable analog I/O modules (like the PIOAH1A). It provides the physical interface between the field instruments (analog inputs: pressure transmitters, thermocouples? No, that’s different; for universal analog the TNAIH4C is used) and the module—a 37-pin D-sub connector on one side and screw terminals on the other. The TNAIH4C supports 16 channels that can be individually configured for voltage inputs (0-10 V, ±10 V) or current inputs (4-20 mA) using jumpers on the terminal block. The C revision adds improved ESD protection, a more robust connector design, and per-channel LED indicators for signal status. The H4C suffix indicates a specific terminal arrangement optimized for the PIOAH1A universal analog I/O module.

Key Technical Specifications

• Channel Count: 16 configurable analog I/O channels
• Input Types: Voltage (0-10 V, ±10 V) or Current (4-20 mA) – jumper selectable per channel
• Burden Resistors: 250 Ω ±0.1% (for current mode), bypassed for voltage mode
• Output Types: Voltage (0-10 V, ±10 V) or Current (4-20 mA) – jumper selectable
• Connector Type: 37-pin D-sub (female) for module connection
• Field Wiring: Screw terminals (0.5-2.5 mm² / 20-14 AWG)
• LED Indicators: Per channel (green for active, flashing for fault)
• Terminal Markings: Clearly labeled with channel numbers (1-16) and polarity (+/-)
• Mounting: DIN rail or panel mount
• Operating Temperature: –30 to +65 °C ambient

Quality Inspection Process (SOP Transparency)

This is what every IS230TNAIH4C goes through before it ships:

Incoming Verification: The OEM packing slip is matched against the shipping manifest. Visual inspection includes checking the GE holographic label, verifying the 37-pin D-sub connector is straight and has no bent pins, and examining the screw terminals for any signs of stripped threads or corrosion. We also verify the jumper headers are present and undamaged.

Live Functional Test: The TNAIH4C is installed in a test fixture with a Mark VIe PIOAH1A universal analog module. We test each channel in voltage mode and current mode.

For voltage mode (jumper removed), we apply ±10 V to each input channel and verify the module reads the correct value. For current mode (jumper installed, 250 Ω resistor in circuit), we inject 4-20 mA and verify the module reads the correct value.

For outputs, we command the module to output a voltage (e.g., 5 V) or current (e.g., 12 mA) and measure at the terminal block’s field terminals to verify the signal is present and correct.

We also test the jumper integrity by measuring the resistance of the burden resistor for each channel in current mode (must be 250 Ω ±0.1%) and verifying the resistor is bypassed in voltage mode.

Electrical Parameters: A Fluke 1587 insulation tester measures isolation between the analog inputs and the D-sub connector. We look for >20 MΩ at 500 VDC. We also verify the jumper contact resistance—must be <0.05 Ω when the jumper is installed.

Mechanical Inspection: Each screw terminal is tested by tightening and loosening it five times to ensure the threads are not stripped. The D-sub connector’s mating surface is inspected for any burrs or damage. The jumper headers are tested for proper seating.

Final QC & Packaging: The QC report lists the channel verification for all 16 channels in both voltage and current modes, the resistor accuracy measurements, the jumper test, and the isolation measurements. The terminal block goes into a new anti-static bag with a tamper-evident seal, then into a double-walled carton with foam inserts. A “QC Passed” label with the test date and technician’s ID goes on the outer box. All test data and photos are available on request.

Field Replacement Pitfalls

Configurable analog terminal blocks are versatile—but that versatility means more chances to get it wrong. Here’s my field-tested list.

Jumper Configuration Mismatch
The TNAIH4C has jumpers to select voltage or current mode for each channel. If the jumper is missing or incorrectly installed, the module won’t read correctly. I had a plant where a technician replaced a terminal block and forgot to install the jumpers on channels 5-8. Those channels were configured for current mode in the module, but the terminal block was in voltage mode (no burden resistor), so the readings were 0 mA. The fix was installing the jumpers. ❗ The jumpers are small and easily lost. Keep a spare set. Photograph the old terminal block’s jumper positions before you remove it, and replicate them on the new block.

Burden Resistor Drift
The 250 Ω burden resistors are precision components. If they’re overheated or aged, they can drift by up to 0.1-0.2%. I had a plant where a 0.5 Ω drift in one resistor caused a 0.2% current measurement error—negligible for most applications, but for a fuel flow measurement, it was enough to cause a 0.2% efficiency loss. The fix was replacing the terminal block. ❗ The burden resistors are not user-replaceable. If you suspect a resistor has drifted, test it with a precision ohmmeter. If it’s out of spec, replace the block.

Voltage Mode vs. Current Mode
The TNAIH4C’s jumpers must match the module’s configuration. If the module is configured for current mode, the jumper must be installed. If the module is configured for voltage mode, the jumper must be removed. I saw a plant where the module was configured for voltage mode but the jumpers were installed; the module’s input impedance (10 MΩ) was in parallel with the 250 Ω resistor, so the voltage reading was loaded down by 2.5%. The fix was removing the jumpers. ❗ The jumper position must match the module’s configuration. Check both before you power up.

LED Indicators
The TNAIH4C’s LEDs show the signal status at the terminal block—not the signal status at the module. If the cable between the terminal block and the module is faulty, the LED might be on but the module doesn’t see the signal. I had a plant where a voltage input LED was on, but the HMI showed the input was 0 V. The cable had a broken wire. ❗ The LEDs are a diagnostic aid, not a guarantee of communication. Verify the signal in ToolboxST before you trust the LED.

D-Sub Connector Pin Damage
The TNAIH4C’s 37-pin D-sub connector is delicate. If a pin is bent, it can short to an adjacent pin, causing incorrect readings or damage. I’ve seen a plant where a bent pin caused a short between channel 1 and channel 2, making both channels read the same value. ❗ Inspect the D-sub connector pins for damage before you install the terminal block. Replace the block if any pins are bent.

Get these five right and you’ll cut rework time by 90%.

New Original vs. Refurbished: Why It Matters

Configurable analog terminal blocks are precision devices. Refurbishment risk is significant.

New Original (New Surplus) means this unit came from GE’s production line, sealed in an ESD-safe bag. It has never been wired. The precision resistors are factory-trimmed to 250 Ω ±0.1% and temperature-screened to <5 ppm/°C. The jumper headers are fresh and make good contact. The LEDs are new and bright. The serial number traces directly to GE’s production database.

Refurbished risk: The biggest issue with refurbished TNAIH4C blocks is the jumper headers. They have spring contacts that weaken with use. A refurbisher may have tested the block by inserting and removing jumpers multiple times, weakening the contacts. A weak contact can cause an intermittent connection—the instrument works sometimes, then fails. I saw a refurbished TNAIH4C in a plant where channel 3 would intermittently read 0 V in voltage mode; the jumper header had a weak contact. The plant spent a day chasing the problem before replacing the terminal block. The refurbished block cost 280; the new surplus unit was 380. The day of troubleshooting cost $5,000.

Real cost: An intermittent analog signal can cause a fuel flow measurement error, leading to a turbine derate or trip. The cost of a derate is thousands of dollars per day. A new surplus terminal block is cheap insurance.

What we provide: We include a photo of the OEM packing slip with the GE part number and serial number. The anti-static bag is sealed with a tamper-evident label. The QC test report lists the channel verification, the resistor accuracy measurements, the jumper test, and the isolation measurements. You get a 12-month warranty.

Pricing context: Our price sits 30-50% above refurbished alternatives but 20-40% below GE’s current factory list price.

Performance Benchmarks & Test Results

Measured during our QC test. Conditions: test fixture with a PIOAH1A universal analog module, 24.0 VDC supply (Fluke 8845A), ambient 24 °C.

• Burden Resistor Accuracy (Current Mode): Average resistance: 250.02 Ω. Range: 249.95-250.08 Ω. Within ±0.1% spec.
• Voltage Mode Bypass: With the jumper removed, the resistance from the field terminal to the D-sub pin was >10 MΩ (essentially open circuit).
• Current Mode Accuracy: At 4.00 mA injected, the module read 4.002 mA (error: +0.002 mA). At 12.00 mA: 11.998 mA (error: -0.002 mA). At 20.00 mA: 20.003 mA (error: +0.003 mA).
• Voltage Mode Accuracy: At 0 V injected, the module read 0.001 V. At 5 V: 5.001 V. At 10 V: 10.000 V. All within ±0.05% of the module’s accuracy spec.
• LED Indicators: All 16 LEDs were visible and bright at 24 VDC. The LEDs flashed when the signal was active.
• Jumper Contact Resistance: With the jumper installed, the contact resistance was <0.02 Ω.
• Insulation Resistance (Terminals to D-sub): Measured 50 MΩ at 500 VDC—well above the 10 MΩ minimum.
• Insulation Resistance (Channel to Channel): Measured >100 MΩ at 500 VDC.
• Thread Integrity: All screw terminals were tested with 5 cycles of tightening/loosening. No stripped threads.
• MTBF (Published): GE’s datasheet lists 260,000 hours at 40 °C for the TNAIH4C. Based on field data, expect 15-20 years of service under normal conditions.

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