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Insulation Resistance test
1. Short-circuit the + and - SUPPLY terminals in the terminal
box.
2. Turn OFF the insulation tester. Then connect the
insulation tester plus (+) lead-wire to the shorted SUPPLY
terminals and the minus (-) lead wire to the grounding
terminal.
3. Turn ON the insulation tester power and measure the
insulation resistance. The voltage should be applied briefly
to verify that insulation resistance is at least 20MΩ.
4. After completing the test and being very careful not to
touch exposed conductors. Disconnect the insulation
tester and connect a 100kW resistor between the
grounding terminal and the short-circuiting SUPPLY
terminals. Leave this resistor connected at least three
seconds to discharge any static potential. Do not touch the
terminal while it is discharging.
Dielectric Strength Test
a. Short-circuit the + and - SUPPLY terminals in the terminal
box.
b. Turn off the dielectric strength tester. Then connect the
tester between the shorted SUPPLY terminal and the
grounding terminal. Be sure to connect the grounding lead
of the dielectric strength tester to the ground terminal.
c. Set the current limit on the dielectric strength tester to
10 mA, then turn on the power and gradually increase the
tester voltage from '0' to the specified voltage.
d. When the specified voltage is reached, hold it for one
minute.
e. After completing this test, slowly decrease the voltage to
avoid any voltage surges.
2.10 Explosion-Proof Rating
2-10-1. FM Certification
HAZARDOUS LOCATION ELECTRICAL EQUIPMENT
Equipment Rating: Explosion-Proof for use in Class I, Division 1,
Groups A, B, C and D;
Dust- Ignition-Proof for Class II/III, Division 1, Groups E, F and G;
Nonincensive for use in Class I, Division 2, Groups A, B, C and D;
Suitable for use in Class II, Division 2, Groups E, F and G;
and Suitable for Class III, Division 1;
Hazardous (classified) location, indoor and outdoor
(NEMA Type 4X/IP67).
2.11 EMC Conformity Standards
EMI (Emission): EN55011
EMS (Immunity): EN50082-2
Dwyer Instruments, Inc. recommends customer use metal conduit
wiring or twisted pair shield cable for signal wiring to conform with
EMC regulation, when installing the Mercoid
®
3100 transmitters.
Chapter 3 Transmitter Functions
3.1 Overview
This Chapter contains information on operating the Model 3100.
Tasks that should be performed on the bench prior to installation are
explained in this chapter.
3.2 Safety Message
Procedures and instructions in this chapter may require special
precautions to ensure the safety of the personnel performing the
operations. Potential safety issues are indicated by a warning
symbol (▲). Refer to the following safety messages before
performing an operation preceded by this symbol.
3.3 Warning
Warning
Explosion can result in death or serious injury:
• Do not remove the transmitter covers in explosion
environments when the circuit is powered.
• Transmitter covers must be fully engaged to meet
explosion-proof requirements.
Warning
Electrical shock can result in serious injury:
• Only qualified personnel can install the transmitter.
3.4 Fail Mode Alarm
Mercoid
®
Smart Pressure Transmitter automatically and
continuously performs self-diagnostic test. If the self-diagnostic test
detects a failure, the transmitter drives the output outside of the
normal operation values. The transmitter will drive its output low
(down) or high (up) based on the position of the failure mode alarm
jumper. See Table 3.1 for output values.
[Table 3.1 Standard Alarm and Saturation Values]
Warning
Electrical shock can result in serious injury:
• Avoid contact with the leads and terminals. High
voltage, that may be present, on leads can cause
electrical shock.
Fail Safe mode can be set via Jumper switches provided on the LCD
module or the main CPU module. The jumper switch for an
indicating transmitter, located on the LCD module, can be set to the
right (fail down i.e. ≤ 3.75 mA) or left (fail up i.e. ≥ 21.75 mA). For
non-indicating transmitters the jumper switch is located on the main
CPU module, it can be set up (fail up to ≥ 21.75 mA) or down (fail
down to ≤ 3.75 mA). Refer to Figure 3-1 for detailed summary of
jumper settings for both CPU and LCD modules.
Level
Low/Down
High/Up
4~20 mA Saturation
3.9 mA
20.8 mA
4~20 mA Alarm
≤ 3.75 mA
≥ 21.75 mA
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