Epson EM07ZS1647F manual 118

4. Troubleshooting (PROFIBUS DP)

♦ Causes of Error

Possible Cause		Examination Method	Countermeasure
{ Disconnected	(1)	Check that terminating	Fix the problem.
terminating		resistors are connected to
resistors		both ends of the network.	How to find the trouble
{ Cable	(2)	Measure resistance between	point:
disconnection		signal wires with device	Remove the terminating
{ Disconnected		power supply OFF.	resistor on one end of the
connector	→ Normal: 100 to 120 Ω		network. The trouble point
{ Disconnected	z Measuring point: Connection		is where resistance changes
signal wire	of the trouble unit		from 220 Ω.
	z For detail, refer to the section
	4.2.3.1 Connection Problem.
{ Loose connector	Check for the connection of		Connect the connectors and
{ Loose signal wire	connectors and signal wires.		signal wires again.
	→ The connectors and signal
	wires should be firmly
	connected.
	z Checkpoint: all stations and all
	branch taps
	z For details, refer to the section
	4.2.3.2 Loose Connector and
	Signal Wire.
{ Electrical surges of	Measure voltage of device power		Check voltage of the device
device power	supply at the trouble unit.		power supply.
supply	→ It should be within the range
	of sufficient voltage for device
	operation.
{ Noise	Check the noise intrusion via the		Take countermeasures
(external cause)	following paths (1) to (3).		against noise.
	(1)	Noise via shield
	(2)	Induced noise via
		communication cable
	(3)	Device power supply
	→ For details, refer to the section
	4.2.3.3 Noise Intrusion.
{ Broken unit	Replace the trouble unit with a		Replace the unit with a new
	new one.		one.
	→ Verify whether the problem is
	fixed.
z No cause is	Identify the trouble point by
identified.	dividing the network.
	→ For details, refer to the section
	4.2.3.4 Broken Unit
	Examination.

118 Fieldbus I/O Rev.6