IC670ALG310-JA Replacement | GE Fanuc Analog Module

Description

Product Introduction (Anti-Template)

Positioning a control valve or driving a variable frequency drive from a GE Series 90-30? That analog signal has to come from somewhere. The IC670ALG310-JA is that somewhere. It’s the 8-channel analog output module for the Field Control line, taking the digital commands from the bus interface unit and converting them to the 4-20 mA signals that actually move things in your process.

This module sits out in the field, not in the main rack, which is the whole point of distributed I/O. It reduces wiring runs by placing the I/O closer to the devices. The value here is straightforward: eight isolated outputs in a single compact block, communicating back to the PLC over a single bus cable. It cleans up the panel, simplifies troubleshooting, and for a retrofit, it beats pulling bundles of new wire from the main control room.

Key Technical Specifications

Compatible Replacement Models

The Field Control line has specific compatibilities. Here is how to navigate replacements and alternatives.

• ✅ Drop-in Replacement: IC670ALG310 (any suffix, e.g., -JA, -JD)
  The base model is IC670ALG310. The suffix (like -JA, -JB, -JD) typically indicates the termination style or a minor hardware revision. Functionally, all IC670ALG310 modules are identical in terms of resolution, channel count, and communication protocol. You can swap a -JA for a -JD without any software changes—just ensure the wiring matches the terminal block labeling.
• ⚠️ Software Compatible: IC670ALG230
  This is the analog input version. It fits in the same Field Control rack and uses the same bus structure. However, the configuration in the PLC software (Logicmaster or Proficy) must define the slot as an input module. It’s not a replacement for an output module, but if you are reconfiguring a drop, the physical mounting and bus connection are identical.
• ❌ Hardware Incompatible: IC693ALG392
  This is an analog output module for the Series 90-30 main rack (backplane), not for Field Control. The physical form factor is different (it’s a standard PLC module), and it uses the parallel backplane, not the Field Control serial bus. You cannot use it in a Field Control drop without extensive modification, which isn’t practical.

 Frequently Asked Questions (FAQ)

Does the IC670ALG310-JA require loop power?
Yes. The module provides the signal conditioning and D/A conversion, but it does not power the loop. You must supply an external 24 VDC power source to the field side of the outputs. Check the wiring diagram for your specific termination block—there are typically terminals for +24V and Common that feed the outputs. Without this external power, you’ll get 0 mA on all channels even if the module is communicating.

Why does my channel output stay at 4 mA even when the PLC says 100%?
This usually points to a wiring issue or a bad loop. First, check your load resistance. If the total resistance in the loop exceeds 600 ohms, the module cannot drive the signal. Second, verify the 24V loop power is present and clean. If those check out, the issue could be the D/A converter for that specific channel has failed—we see this most often on channels that have seen a field short circuit.

How do I know if the module is communicating with the BIU?
Look at the OK LED on the front of the module. If it’s solid green, the module has power and is communicating with the Bus Interface Unit. If it’s blinking or off, there is a communication problem. Check the backplane connections, the BIU configuration, and the bus terminator (if required). To be frank, we’ve seen more communication faults from loose modules in the rack than from actual electronics failure.

Can I replace this module with the system powered?
The Field Control system is not designed for true hot-swapping. While the backplane connectors are keyed and the bus can sometimes handle a brief interruption, it’s risky. Removing a module while the bus is active can glitch the communication for the entire drop, affecting all I/O in that rack. We recommend powering down the drop’s 5V logic supply before swapping.

What is the difference between IC670ALG310-JA and -JD?
The difference is purely in the termination block. “-JA” typically refers to a specific style of terminal strip or connector. The electronics board underneath is identical. If you have a mix of suffixes in your plant, keep a spare module and a spare terminal block on hand. That way, if a -JA fails, you can keep the existing wiring intact and just swap the electronics board.

My outputs are jittery or inaccurate. What should I check?
Start with the field power. A noisy or under-spec 24V supply can cause jitter. Check for ground loops—are your field devices sharing a common ground with the module in a way that creates a potential difference? If the power and wiring are clean, the issue could be internal. The 12-bit resolution is decent but not high precision. You may be seeing quantization error if you need very fine control. Consider scaling the signal in the PLC to use more of the 4-20 mA range.

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