JB2
5-2-55, Minamitsumori, Nishinari-ku, Osaka 557-0063 JAPAN
Phone: +81(6)6659-8201 Fax: +81(6)6659-8510 E-mail: [email protected]
EM-2642 Rev.3 P. 4 / 5
Modification Code
D: No modification (writing) possible. Used only for monitoring (reading).
S: Modifiable at any time.
P: Modifiable only when the MAINTENANCE SWITCH is in the ‘PRG’ mode.
*1. RUN contact is open (coil de-energized) while in the programming mode.
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CAS INPUT HIGH/LOW ALARM
• Alarm Trip
The High/Low alarm trips when the CAS input signal reaches or goes beyond the respective setpoints specified with ITEM
26/27.
[Example] Low setpoint at 0.00%
The alarm trips when the input goes below 4.00mA.
• Alarm Reset
The High/Low alarm is reset when the CAS input signal goes out of the alarm zone by 1% deadband.
[Example] Lo setpoint at 0.00%
OPERATING MODES
The alarm is reset when the input goes above 4.160mA, at 4.161mA or more.
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CASCADE CONTROL MODE
The JB2 allows the CAS input (cascade control signal) from the PID controller to pass through at the MV output terminals.
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MANUAL CONTROL MODE
When the external MAN command contact is closed, the JB2 turns on to manual control mode.
Actual output signal is determined by following three operation modes:
MODE 1: Holds the CAS control signal at the moment of the MAN command.
MODE 2: Goes back the preset time period and hold the CAS control signal at that moment.
MODE 3: Holds a specific value preset by the Programming Unit (PU-2x).
In this mode, the output can be manipulated with external UP or DOWN commands.
When the MAN command contact is opened, the CAS control signal is recovered with smooth transition.
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TRANSITION FROM MAN TO CAS CONTROL MODE
The JB2 increases/decreases the MV output until it reaches to the same value as the CAS control signal, and turns on to CAS
control mode. The response time constant can be set/changed with the PU-2x.
If the external command contact is closed during the transition, the JB2 output holds the signal of this moment and turns on
to MAN control mode.
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JB2 ACTIONS WHEN THE POWER SUPPLY IS RECOVERED AFTER FAILURE
OPERATING MODE
BEFORE FAILURE
MAN COMMAND
STATUS AT RECOVERY
ITEM 31: 0
ITEM 31: 1
CASCADE
OFF (CAS mode)
Cascade control action
Cascade control action
ON (MAN mode) *
1
Manual control starting with the
CAS control signal at the moment
of failure
Manual control starting with a
specific value preset in ITEM 30
MANUAL
OFF (CAS mode)
Cascade control action
Cascade control action
ON (MAN mode) *
1
Manual control holding the MAN
control signal at the moment of
failure
Manual control starting with a
specific value preset in ITEM 30
SLIDING-BACK
OFF (CAS mode)
Cascade control action
Cascade control action
ON (MAN mode) *
1
Manual control holding the transi-
tion signal at the moment of failure
Manual control starting with a
specific value preset in ITEM 30
*1. Approx. 0.3 seconds is required to switch from CAS to MAN when the power supply is recovered.
