Dwyer MS2 - Manual (Page 2)

Power Supply
Refer to the below table for the required supply rating.
Choose a power supply with a voltage and current rating sufficient to meet the power
specifications under all operating conditions. If the supply is unregulated, make sure
that the output voltage remains within the required voltage range under all power line
conditions. Ripple on the supply should not exceed 100 mV.
aC/DC Jumper Selection
Refer to Figure 1 for the location of the AC / DC jumper. Place the shorting jumper
across either the two pins marked AC or the two pins marked DC.
figure 1
2-Wire 4 to 20 ma Current Operation
The connections to the transmitter are made through terminals 2 and 3 on the terminal
block as shown in Figure 2. The terminal block is removable and each of the terminals
are labeled underneath the terminal block on the circuit board. Polarity is indicated by
+IOUT and -IOUT. The AC/DC selection jumper should be set for DC operation.
figure 2
The range of appropriate receiver load resistances (RL) for the power supply voltage
available is given by the formula listed below. Shielded 2-wire cable is recommended
for control loop wiring. Ground the shield at the power supply end only.
The maximum length of connecting wire between the transmitter and the receiver is
a function of wire size and receiver resistance. That portion of the total current loop
resistance represented by the resistance of the connecting wires themselves should
not exceed 10% of the receiver resistance. For extremely long runs (over 1,000 feet),
it is desirable to select receivers with lower resistances in order to keep the size and
cost of the connecting leads as low as possible. In installations where the connecting
run is no more than 100 feet, connecting lead wire as small as No. 22 ga. can be
used.
3-Wire 0 to 10 V and 0 to 5V Voltage Operation
The connection to the transmitter are made to Terminals 1, 2, and 3 on the terminal
block as shown in Figure 3. The terminal block is removable and each of the terminals
are labeled underneath the terminal block on the circuit board. Polarity is indicated by
PWR, COM, and +VOUT. When connecting using a DC power source, make sure the
AC/DC selection jumper is set for DC. If the polarity of the transmitter is inadvertently
reversed, the unit will not function properly, but no damage will be done to the
transmitter. When connecting to an AC power source, make sure the AC/DC selection
jumper is set for AC. Either lead of the supply power may be connected to PWR and
COM without affecting the operation of the transmitter or damage to the transmitter.
figure 3
The minimum receiver load is 1K Ω. The resistance due to the wire should be low
compared to the receiver load resistance. While the voltage at the terminal block
remains unchanged with a 10 mA current flow, resistive losses in the wiring do cause
errors in the voltage delivered to the receiver. For a 1% accurate gauge, the
resistance of the wires should be less than 0.1% of the value of the receiver load
resistance. This will keep the error caused by the current flow below 0.1%.
The output across +VOUT and COM will be either 0 to 5 V, 0 to 10 V, or the inverse
depending on the dip switch setting. See Dip Switch Setting Section for more
information.
The jumper is factory set to AC. If DC power is applied while the
jumper is set to AC, no damage will occur. However, the
accuracy of the unit may temporarily be affected.
NOTICE
Output Type
2-Wire Current
3-Wire Voltage
Simultaneous Current
and Voltage
Power Supply Rating
10 to 40 VDC (40 mA min)
17 to 40 VDC or 21.6 to 33
VAC (40 mA min)
17 to 40 VDC (40 mA min)
11 22 33
11
22
33
44
55
66
77
ZERO ZERO
SPAN SPAN
DC DC
AC AC
AC/DC JUMPER AC/DC JUMPER
11 22 33
11
22
33
44
55
66
77
ZERO
SPAN
POWER RECEIVER
++ ++
__ __
CURRENT OUTPUT WIRING
The receiver may be connected to either the negative or
positive side of the loop, whichever is most convenient. Should
polarity of the transmitter or receiver be inadvertently reversed, the loop will not
function properly but no damage will be done to the transmitter.
NOTICE
11 22 33
11
22
33
44
55
66
77
ZERO
SPAN
POWER RECEIVER
++
++
__ __
VOLTAGE OUTPUT WIRING
Powering the unit with AC power while the jumper is set to DC
may permanently damage the transmitter. CaUTION
DO NOT EXCEED SPECIFIED SUPPLY VOLTAGE RATINGS.
PERMANENT DAMAGE NOT COVERED BY WARRANTY
WILL RESULT. SIMULTANEOUS OUTPUTS ARE NOT DESIGNED FOR AC
VOLTAGE OPERATION.
CaUTION
DO NOT EXCEED SPECIFIED SUPPLY VOLTAGE RATINGS.
PERMANENT DAMAGE NOT COVERED BY WARRANTY
WILL RESULT.
CaUTION
R
L
=
V
ps
- 10.0
20 mA DC