How to troubleshoot Siemens Control Unit when analog input/output points are not reading as expected?
If the analog input/output points on your Siemens Control Unit aren't reading correctly, verify that all slope/intercept entries are correct. Also, ensure the sensor is functioning properly and replace it if necessary.
What to do if the RUN LED is off on Siemens PXC-24 Compact Control Unit?
If the RUN LED is off on your Siemens Control Unit, first verify that power is connected. Then, check the service box and transformer ON switches. If power is ON, verify that the application firmware has booted. Finally, measure voltage on 24V~ and (Terminals 1 and 2).
How to fix Siemens PXC-24 Compact when points cannot be read or commanded from the operator's terminal?
If points cannot be read or commanded from the operator's terminal on your Siemens Control Unit, verify that any failed points have been properly addressed. Also, verify the status of the points at the operator's terminal and ensure that points are not under Operator priority.
What to do if the RUN LED is ON but no communication is possible with the HMI port on Siemens PXC-24 Compact?
If the RUN LED is ON but there's no communication with the HMI port on your Siemens Control Unit, verify that the HMI port and your terminal are set to the same communication speed. Also, ensure that the cable from the field panel to the operator's terminal is properly connected at both ends. Open the enclosure and verify that both ends of the HMI extension cable are properly connected. Try unplugging the extension cable and plugging directly into the HMI port.
Why is there no communication over the ALN trunk on Siemens Control Unit?
If there is no communication over the ALN trunk on your Siemens Control Unit, and the TX and RX LEDs are off or on solid, verify that the ALN trunk is securely connected to the ALN port on the Field Panel. On a two-wire ALN trunk, verify that the shield is connected to the enclosure ground and not the S-pin. Verify the field panel address and communication speed. Also, verify that the extended ALN trunk is operating.
How to troubleshoot Siemens Control Unit when LAI point does not function properly?
If an LAI point on your Siemens Control Unit isn't functioning correctly or shows as failed (*F*), verify that the field input device is within range. Also, make sure that points are properly terminated on the termination board or module. Confirm that the correct voltage is supplied to the device, as in a 4 to 20 mA device.
How to troubleshoot Siemens Control Unit when LAO point does not function properly?
If an LAO point on your Siemens Control Unit is not functioning properly, displays as failed (*F*), and the output doesn't change when commanded, verify that the device connected to the point is functioning properly and is not shorted out. Also, verify that points are properly terminated on the termination board or module. Finally, verify that the correct voltage is supplied to the device.
How do I fix no communication over the FLN trunk on Siemens PXC-24 Compact?
If there is no communication over the FLN trunk on your Siemens Control Unit, verify the FLN address and communication speed. Also, verify the FLN trunk is connected to the correct FLN port.
Why does the BATT LOW LED remain on after battery replacement in Siemens PXC-24 Compact Control Unit?
If the BATT LOW LED remains on after replacing the battery in your Siemens Control Unit, verify that the correct type of battery is being used. The LOW BATT LED remains ON if an alkaline battery is used in PXC Compact models with extended temperature range operation.
General| Number of I/O Points | 24 |
|---|---|
| Power consumption | 15 VA / 8 W |
| Operating temperature | -20 °C to +60 °C |
| Mounting Type | DIN rail |
| Mounting | DIN rail |
| Dimensions | 160 x 140 x 70 mm |
| Protection class | IP20 |
| Enclosure Rating | IP20 |
| Supply voltage | 24 V DC |
| Power Supply | 24 V DC |
| Communication Protocols | BACnet MS/TP, Modbus RTU |
| Communication | BACnet MS/TP, Modbus RTU |
| Communication Interface | RS-485 |
| Storage Temperature | -40 °C to +70 °C |
| Relative Humidity | 10% to 95% (non-condensing) |
Covers firmware revision, licensing, and an introduction to supported point types.
Lists configurable and dedicated point types for PXC-16, PXC-24, and PXC-36 models.
Details memory types, Flash ROM, RAM, and backup batteries (AA, coin cell).
Covers communication connections, specs, and diagrams for HMI, Ethernet, RS-485.
Explains what PXC Compact on P1 is and its three-part database structure.
Details P1 mode applications, point mapping, and operational aspects.
Troubleshoots TX-I/O Island Bus errors, module failures, and component replacement.
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