Simplex 4100ES — Channel Fail

The control unit display reads Channel Fail. The manuals print the message in this wording only; where quotation marks appear around it in the fault tables, the text is identical. It is an IDNet channel status message shown by the fire alarm control unit.

Devices have been configured on the IDNet channel, but none of the configured devices are communicating on the channel. The message appears when at least one device on the IDNet channel has been configured and no devices are communicating; it does not appear if there are no configured devices on the IDNet channel, so seeing it confirms that the channel does have configured devices. On the hardware, LED2 steady on corresponds to the same state — channel failure, that is, communication problems with configured devices. The fault tables list no corrective action for this message.

• None of the configured devices are communicating on the IDNet channel — at least one device on the channel has been configured, but no devices on the channel are communicating.

1. Look at LED2, which is normally off and illuminates to indicate a problem with the IDNet lines. Steady on indicates channel failure — communication problems with configured devices.
2. Read the blink pattern to tell this trouble apart from other line conditions: one repetitive blink of LED2 indicates a line short, and two repetitive blinks indicate a Class A failure or an open line. Only the steady-on state corresponds to Channel Fail.
3. Check the SPS: its status LED indications include a steady-on state for No devices detected/ channel failure.
4. Check the IDNet wiring against the manual's limits: 40 Ohms maximum loop resistance and 0.58 μF capacitance maximum (line to line and shield to line).
5. Check the channel voltages: the IDNet input is 24 VDC nominal (24V Card Supply from SPS), and the voltage output to IDNet is normally 30VDC, increased to 35VDC when LEDs, piezos, or other outputs are activated, as in the alarm state.

• IDNet input voltage: 24 VDC nominal (24V Card Supply from SPS).
• Comms/power voltage to IDNet slaves: 30 VDC nominal, or 35 VDC @ 250 mA; the output is normally 30VDC and is increased to 35VDC when LEDs, piezos, or other outputs are activated, as in the alarm state.
• Wiring limits: 40 Ohms maximum loop resistance; 0.58 μF capacitance maximum (line to line and shield to line).
• Operating temperature: 0° to 50° C.
• Channel capacity: up to 250 IDNet devices.
• The 30/35V PSU on the IDNet supplies the channel, and the current limit is provided by a PTC.