Product overview
2.2 Functions
ET 200SP F-TM Count 1x1Vpp sin/cos HF (6ES7136-6CB00-0CA0)
22 Equipment Manual, V1.0, 01/2021, A5E47073911-AA
A and B signal monitoring
Signal monitoring evaluates the quality of the A and B signals. The following A and B signal
quality faults can cause a channel diagnostic event to be generated.
• Phase angle of A and B signal has shifted from 90°
• Signal amplitude (voltage) is too great or too small
• Wire break, shorted signals, or encoder failure
Note
If only one of the wires of the differential pair is disconnected (for example, A or A
\), a wire
break may not be immediately detected, and a slight movement of the encoder position is
requi
red to detect the break. Breaking both wires of the differential pair will always be
The module continues monitoring the encoder and accumulating counts while the diagnostic
is present. While the diagnostic is present, a count value of zero and status values of zero
(safe state values) are provided to your safety program. When the error is resolved and the
channel is reintegrated the module will return the accumulated count and status values to
your safety program.
The count value can potentially be affected when a signal quality fault occurs.
Your safety program must determine whether the reported count value remains
representative of actual position. If position is lost, your safety program must do a homing
operation and then reset the counter to its respective start value.
Signal monitoring allows the module to meet SIL, Cat., PL rating. It is possible for a
channel fault to occur that is not readily detected by the module diagnostics if signal
monitoring is disabled.
Disabling this feature reduces the safety rating to SIL 1, Cat. 2, PL c, which causes a loss of
the safety function. Disabling this feature can result in unexpected machine or process
operation, which can cause death, severe personal injury, and/or property damage.
If signal monitoring is disabled, A and B signal or wire break errors detected are not reported
and you might not achieve your required level of safety. You must provide your own safety
measures if you disable these features.
To Next Page
Loading...
Need help?
General
