Dwyer MS2 - Manual (Page 3)

Simultaneous Current and Voltage Operation
The connection to the transmitter are made to Terminals 1, 2, and 3 on the terminal
block as shown in Figure 4. 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. The AC/DC selection jumper should be set
for DC operation. The voltage output and the power supply must have separate
wire leads that are only joined at terminal 2 of the transmitter. Additional error may
occur for the voltage output if a single wire is used or if the wires are joined at the
power supply or receiver.
figure 4
For the current output, the maximum allowable loop resistance (wiring + receiver
resistance) is dependent on the power supply. The maximum loop voltage drop
must not reduce the transmitter voltage below 17 V. The maximum loop resistance
can be calculated using the following equation:
R
MAX
= (VPS – 17.0) / 0.02 Where VPS is the power supply voltage
The equation uses 17.0 instead of 10.0 used in current only equation. This
represents the minimum voltage supply which is higher on the simultaneous output
configuration due to the requirements of the voltage outputs.
Shielded 4-wire cable is recommended for control loop wiring. Ground the shield at
the power supply end only. Should the polarity of the transmitter or receiver be
inadvertently reversed, the unit will not function properly, but no damage will be
done to the transmitter.
For voltage outputs, 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.
DIP SWITCH SETTINGS
DIP Switches can be located next to the terminal block as shown in Figure 5. A
small screw driver or pen can be used to change the position of the switches.
figure 5
factory Settings
Mode = Unidirectional
Range = Highest Range Setting (0.5, 5, or 28 in w.c.)
Units = Inches W.C.
Voltage Output Range = 10 V
Direct / Reverse Output Action = Direct
Setting the Pressure Range
Ranges are selected by adjusting DIP Switch Positions 1 and 2 according to the
below tables. The range also depends on the units selected (Refer to Setting the
Engineering Units Section) and if the input is set for unidirectional or bidirectional
(Refer to the Setting for Unidirectional or Bidirectional Section). The tables below
show the maximum full scale value for the selected range and selected units. If the
unit is set to unidirectional, the ranges are all zero based. If the unit is set for
bidirectional, the ranges will be ± the maximum full scale value shown in the tables
below.
Setting for Unidirectional or Bidirectional
The Models MS2-X101 and MS2-X103 can be set to measure pressure in one
direction or two directions based on the setting of DIP Switch 3. The Model MS2-
X102 can only be set to unidirectional.
• When the switch is in the ON direction, the transmitter will be set for Unidirectional
and will be 0 based (i.e. 0 to 5 in w.c.).
• When the switch is in the OFF position, the transmitter will be set for Bidirectional
and will be ± the maximum of the selected range (i.e. ±5 in w.c.).
• For unidirectional units only, switch has no effect and unit will remain in
unidirectional mode.
DIP Switch full Scale Range for MS2-X101
1
OFF
OFF
ON
ON
2
OFF
ON
OFF
ON
in w.c.
0.1
0.15
0.25
0.5
Pa
25
40
50
125
mm w.c.
2.5
4
6
10
kPa
0.025
0.040
0.050
0.125
DIP Switch full Scale Range for MS2-X102
1
OFF
OFF
ON
ON
2
OFF
ON
OFF
ON
in w.c.
1
2
3
5
Pa
250
500
750
1250
mm w.c.
25
50
75
125
kPa
0.250
0.500
0.750
1.25
DIP Switch full Scale Range for MS2-X103
1
OFF
OFF
ON
ON
2
OFF
ON
OFF
ON
in w.c.
10
15
25
28
Pa
2500
3500
5000
6975
mm w.c.
250
350
500
700
kPa
2.50
3.50
5.00
6.98
11 22 33
11
22
33
44
55
66
77
ZERO ZERO
SPAN SPAN
POWER
VOLTAGE
RECEIVER
CURRENT
RECEIVER
++
++
++
__
__
__
NOTE - POWER
AND VOLTAGE
RECEIVER "-" MUST
BE SEPERATE WIRES
AND BOTH WIRED TO
SIMULTANEOUS CURRENT AND
VOLTAGE OUTPUT WIRING
11 22 33
11
11
22
22
33
33
44
44
55
55
66
66
77
77
ZERO ZERO
SPAN SPAN
ON ON
DIP SWITCH SETTINGS DIP SWITCH SETTINGS
RANGE RANGE
UNITS UNITS
10V 10V
DIR DIR
5V 5V
REV REV
UNIDIRECTIONAL UNIDIRECTIONAL BIDIRECTIONAL BIDIRECTIONAL
All power should be turned off to the transmitter before adjusting
the dip switch settings to avoid electrical shock. WaRNING
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