Pro-face RHAA038: Error responded for device read command (write only devices)

Pro-face HMI Critical Communication

Model: GP4000/SP5000 Series | Code: RHAA038

Applicable Systems
GP4000 Series

Symptoms

  • GP-Pro EX display unit shows error RHAA038: Error responded for device read command (write only devices).

Possible Causes

  • The device/PLC cannot recognize a Read request; the address is a write-only address.

Troubleshooting Steps

  1. Step 1: Check the device/PLC manual; set read operations to addresses that support reading.
    Communication restored and error cleared

How to Reset

Repower or reset the display unit after correcting the root cause.

Related Pro-face Fault Codes

Source: Pro-face GP-Pro EX Maintenance/Troubleshooting Manual, T.7.1 Common Display errors (proface.tech/otasuke official)

Category: HMI