<4. Self-Diagnostics>
4-7
IM 01C50T03-02EN
4.3 Self Check Function
The YTA has the following self-check functions.
(1) Hardware failure
This function detects a failure of CPU, AD converter,
memory and others.
(2) Sensor failure
This function detects an open circuit of sensors.
The transmitter flows the current, and outputs an
open-circuit alarm if the resistance exceeds the
threshold.
Parameter setting: Not required
Alarm output: If the resistance exceeds the
threshold, an S1 Failure (AL.10) or S2 Failure
(AL.11) alarm is output.
(3) Terminal block failure
This function detects an open circuit of CJC. The
transmitter measures the CJC resistance and
notifies of a terminal block failure if the resistance
exceeds the threshold.
Parameter setting: Not required
Alarm output: If the resistance exceeds the
threshold, a Term Sensor Fail (AL.22) alarm is
output.
(4) TC short-circuit (TC)
This function detects a short-circuit of the TC
sensor. The transmitter flows current, and outputs
a short-circuit alarm if the sensor resistance (S1
RP23 for L10, or S2 RP43 for L15) is below the
threshold.
Set the threshold (resistance) using the following
parameters.
Threshold setting
parameter
Alarm detected
Remarks
L20:S1TC SHRT
TH
S1 Short (AL.12)
L22:S2TC SHRT
TH
S2 Short (AL.13)
2-input model
only
NOTE
In order to output the S1 (or S2) Short alarm,
"K12:S1 SHRT MASK" and "K13:S2 SHRT
MASK" must be set to "NO MASK". (The alarm is
masked by default.)
(5) “RTD” or “ohm” short-circuit (for 3-wire/4-
wire type only)
This function detects a short-circuit of the sensor
during “RTD” or “ohm” measurement. If the sensor
resistance drops below the threshold (L11: S1 RC1
to L14: S1 RC4, L17: S2RC4, L16: S2RC4), a
short-circuit alarm is output.
The threshold is fixed to 5 Ω, and parameter setting
is not required.
Threshold setting
parameter
Alarm detected
Remarks
Not applicable
S1 Short (AL.12)
Not applicable
S2 Short (AL.13)
2-input model
only
NOTE
• The alarm mask must be released in order to
output the S1 (or S2) Short alarm. (The alarm
is masked by default.)
• In the case of 3-wire RTD or ohm connection,
if actual connection and connection setting
are imbalanced, an unforeseen alarm may be
generated.
(6) RTD Corrosion (for 3-wire/4-wire type only)
This function detects any corrosion between
terminal block and measurement cables. If the
resistance between the terminal block and cables
(L11:S1 RC1 to L14:S1 RC4, L17:S2 RC3, L16:S2
RC4) exceeds the threshold, a corrosion alarm is
output.
Set the threshold using the following parameters.
Threshold setting
parameter
Alarm detected
Remarks
L21:S1RTD COR
TH
S1 Corrosion
(AL.14)
L23:S2RTD COR
TH
S2 Corrosion
(AL.15)
2-input model
only
NOTE
The alarm mask must be released in order to
output the S1 (or S2) Corrosion alarm. (The alarm
is masked by default.)
