Disconnection Detection Flag (Buffer Memory Address 49: Un\G49) - Mitsubishi Electric Q64RD User Manual

3 SPECIFICATIONS

3.4.11 Disconnection detection flag (buffer memory address 49: Un\G49)

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(1) The disconnection detection flag of the corresponding channel turns to 1 when the
disconnection of the platinum temperature-measuring resistor or conductor is
detected.
(2) Disconnection detection is made on only the channels specified for conversion
enable.
(3) Disconnection is detected on each channel.
(4) The disconnection detection flag is cleared when the Operation Condition Setting
Request (Y9) is turned on.
(5) If disconnection is detected on any of the channels enabled for conversion, the
Disconnection Detection Flag (XC) also turns on.
At the same time, the A/D Conversion Completed Signal (XE) turns off, and the
conversion update of the channel enabled for conversion stops.
b15 b14 b13 b12 b11 b10
0 0 0
(6) The relationships between disconnection detection and conversion enable/disable
are indicated below.
Connection Status
Without
disconnection
With
disconnection
Without
disconnection
POINT
• Any channel where no platinum temperature-measuring resistor is connected
must be specified as "conversion disable".
Not doing so will turn on the disconnection detection flag.
• The temperature conversion value of the channel whose disconnection detection
turned on is held at the value immediately before disconnection detection and the
conversion completed flag of the corresponding channel turns on.
• Refer to Section 4.4 for the platinum temperature-measuring resistor wiring.
• Refer to Section 8.2.5 for the troubleshooting of disconnection detection.
b9 b8
0 0 0 0 0
a
A
B
b
a
A
B
b
a
A
B
b
b7 b6 b5 b4 b3
0 0 0 0 CH.4 CH.3 CH.2 CH.1
Conversion
Enable/Disable
Designation
Conversion enable
Conversion disable
Conversion enable
Conversion disable
Conversion enable
Conversion disable
MELSEC-Q
b2 b1 b0
0: Normal
1: Disconnection
Disconnection
Detection Flag
OFF
ON
OFF
ON
OFF
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