Practical instrument electronics, Simulate 2-wire transmitters, Setting up automatic stepping & ramping – Practical Instrument Electronics 334Plus User Manual

Page 5

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Practical Instrument Electronics

82 East Main Street Suite 3.14 • Webster, NY 14580 Tel: 585.872.9350 • Fax: 585.872.2638 • [email protected] • www.piecal.com

Page 5

2 Wire mA, 2 Wire % (Percent of 4 to 20 mA)

Choose this function to simulate a 2 Wire Transmitter output from 0.000 to 24.000 milliamps.
Operates in loops with power supply voltages from 2 to 100 VDC

Simulate 2-Wire Transmitters

1) Disconnect one or both input

wires from the device to be cali-
brated.

2) Select

“mA” or “% 4 to 20mA”

with slide switch

q

.

3) Select

“2 WIRE” using slide

switch

w

.

4) Connect the red input lead of

the 334Plus to the plus (+) input
of the field connections and the
black lead to the minus (-).

Loop current is adjusted in 0.001 mA
(0.01%) increments by turning the knob

r

while the EZ-CHECK™ switch

e

is in the “DIAL”

position, or the current can be set at the fixed points of 4.000mA (0.00%) or 20.000mA (100.00%)
with switch

e

. Press and turn the knob for faster dialing with 0.100 (1.00%) increments.

Start automatic stepping or ramping by pressing and holding the

r

DIAL KNOB for 3 seconds. The

word STEPPING or RAMPING will flash on the display anytime the selected automatic function is
running. The 334Plus will automatically step or ramp between 4mA & 20mA (or 20mA & 4mA) for 30
seconds then reverse direction. Stop the stepping or ramping by pressing or turning the knob or
moving any switch.

To

Sensor

Typical

2-Wire

Transmitter

(Disconnected)

+ IN - REF +OUT-

Receiver

Powers External

2-Wire Transmitter

Power Supply

(2 to 100 VDC)

2 WIRE

mA

12.002

To change the Automatic Stepping & Ramping settings
Double click the

r

DIAL KNOB at any time the unit is on and the following display will appear for 30

seconds:
Turn the

r

DIAL KNOB to move through the menu. Press the

r

DIAL KNOB to toggle between OFF

and ON or to change the steps setting. These settings are remembered even with the power off.

EXIT MENU - exits this menu immediately and saves any changes. Menu will automatically exit after
30 seconds of inactivity.

STEPS - pressing the knob will cycle from 2, 3, 5 steps and RAMP.

2 steps will automatically switch between 4 & 20 mA (0 & 100%).

3 steps between 4, 12 & 20 mA (0, 50 & 100%).

5 steps between 4, 8, 12, 16 & 20 mA (0, 25, 50, 75 & 100%).

RAMP will continuously ramp the output between 4 & 20 mA (0 & 100%).

Setting Up Automatic Stepping & Ramping

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