Disconnection Detection Flag (Un\G49) - Mitsubishi q64rd User Manual

3 SPECIFICATIONS

3.4.14 Disconnection detection flag (Un\G49)

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(1) The disconnection detection flag of the corresponding channel turns to 1 when the
disconnection of the RTD or wire break is detected.
(2) Disconnection detection availabe for conversion-enabled channels only.
(3) Disconnection is detected on each channel.
(4) The disconnection detection Signal is cleared when the Operating Condition
Setting Request (Y9) is turned on.
(5) If disconnection is detected on any of conversion-enabled channels, the
Disconnection Detection Signal (XC) also turns on.
For a channel where disconnection is detected, a value based on the Conversion
setting for disconnection detection (buffer memory address 148: Un\G148) is
stored in the CH measured temperature value (buffer memory addresses 11 to
14, 54 to 61: Un\G11 to 14, Un\G54 to 61).
Conversion of the channels not disconnected is continued.
For the Q64RD-G, "ALM LED" flashes.
b15 b14 b13 b12 b11 b10
0 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 RTD is connected must be specified as "conversion
disable".
Not doing so will turn on the disconnection detection flag.
• For temperature conversion values to be stored when the Disconnection
Detection Signal (XC) turns ON, any of "Value immediately before
disconnection", "UP scale (maximum value of measured temperature range + 5%
of measured temperature range)", "Down scale (minimum value of measured
temperature range – 5% of measured temperature range)" or "Given value" can
be selected. (Refer to Section 3.2.2.)
• Refer to Section 4.4 for the RTD wiring.
• Refer to Section 8.2.7 for the troubleshooting of disconnection detection.
b9 b8 b7
0 0 0 0 0
Conversion Enable/
Disable Setting
a
Conversion enable
A
B
b
Conversion disable
a
Conversion enable
A
B
b
Conversion disable
a
Conversion enable
A
B
Conversion disable
b
MELSEC-Q
b6 b5 b4 b3 b2
0 0 0 CH4 CH3 CH2 CH1
0: Normal
1: Disconnection
Disconnection
Detection Flag
b1 b0
OFF
ON
OFF
ON
OFF
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