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Set-Up Instructions (Cont.)
SET-UP OF THE UCM-420A IN THE SAMPLE AND HOLD
D
MODE (SEE PAGE 12)
For Direct-Acting Output (4-20 mA in and 4-20 mA out or 1-5 VDC in and 1-5 VDC out) switch A3
STEP
and A4 should be "ON" and all other switches "OFF". For Reverse Acting Output (4-20 mA in and
E-1
20-4 mA out or 1-5 VDC in and 5-1 VDC out) switch A4 should be "ON" and all other switches "OFF."
STEP
Set the jumpers as shown in TABLE 23 for the signal being monitored.
E-2
Signal Monitored
OPERATION
The UCM-420A may be used to sample an analog signal and hold the value on a loss of signal. In this mode of
operation, the analog remote setpoint signal is sampled and the local setpoint and input signals are ignored. The
"lost" threshold for the sampled signal is 3.2 mA or 0.8 volts.
The remote setpoint signal is sampled once per second. If the new value is within 6% of the previous reading, the
new value is passed through to the output.
If the new sample of the signal is more than 6% higher or lower than the previous sample but is not "lost" (the input
signal is moving), the old output value is held. The new sample is then saved for comparison against the next
sample. When the input signal stops moving so that two consecutive samples are within 6% of each other, the
output updates.
When the newest sample of the signal drops below the "lost" threshold value, the old value is held at the current
output.
On power loss, the current output value is remembered up to 6 hours. On power return, if the sampled signal is
"lost," the old value will be output until a good signal is received.
WIRING OF THE UCM-420A IN THE SAMPLE AND HOLD MODE
UCM-420A
TIME
MUX
PROP
B3
B4
B5
ADDR
B6
B7
B8
BASE
A6
A7
A8
T.R.
2.65
0
0
0
1
0
0
0
0
0
0
10%
0
0
1
0
0
1
5.2
0
0
1
2
20%
0
1
0
3
0
1
0
12.85
0
1
0
35%
25.6
0
1
1
4
0
1
1
0
1
1
50%
1
1
.59-2.93
1
0
0
0
5
X
X
0
65%
1
0
1
1
0
1
6
80%
RESET
1
1
0
7
1
1
0
90%
PER MIN
A4
A5
1
1
1
8
1
1
1
100%
OFF
0
0
0
1
0.5
"1" MEANS
"0" MEANS
1
1
0
TURN SWITCH ON
TURN SWITCH OFF
2
1
1
SWITCH OFF
SWITCH ON
A3
REVERSE ACTING
DIRECT ACTING
A2
BOTH OFF >> REMOTE SETPT
LOCAL SETPT ENABLE
A1
REMOTE SETPT ENABLE
SAMPLE AND HOLD MODE
B1
BOTH OFF >> ANALOG
PWM REM SETPT SGLE UNIT
B2
REMOTE SETPOINT
PWM REM SETPT MUX MODE
TABLE 23
4-20 mA
1-5 VDC
1 2 3 4 5 6 7 8
A
1 2 3 4 5 6 7 8
B
STATUS
PWM
1
INPUT
PWM
2
INPUT
3
+
REM SPT
INPUT SIGNAL
INPUT
4
–
LOC SPT
5
POT +
MONITORED
6
LOC SPT
INPUT
7
LOC SPT
8
POT –
FEEDBK
9
INPUT
10
24 PWR
11
COMMON
–
OUTPUT SIGNAL
12
+
MA SIG
TO SYSTEM
OUTPUT
+
24 VAC OR 24 VDC POWER
–
26
Set jumper plugs on
Positions 1, 7, & 11
Positions 2, 7, & 11
LED INDICATION
Steady Green
- Signal O.K.
Dark
- Power Loss
Steady Red
- Signal Lost, Output Being Held
Slow Red/Green Blink - Signal Changing Rapidly.
Output Being Held
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