Disconnection Detection Flag (Un\G49) - Mitsubishi Electric 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) Disconnection detection flag is cleared when Operating Condition Setting Request
(Y9) or Error Clear Request (YF) 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 measured temperature 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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