Pyromation SERIES 401 - Manual

INSTALLATION AND OPERATING INSTRUCTIONS
SERIES 401 RTD TEMPERATURE TRANSMITTER
5211 Industrial Road • Fort Wayne, IN 46825 USA • (260) 484-2580 FAX : (260) 482-6805 • http://www.pyromation.com 3/02
 Copyright 2002 Pyromation, Inc. All rights reserved. Form 401f
General Information
The Pyromation Series 401 RTD temperature transmitter is a “two wire” loop powered resistance to current
transducer. This transmitter will produce a linearized (4 to 20) mA dc output current proportional to the
temperature of the RTD temperature sensor.
The transmitter’s small size allows universal mounting
inside Series 300, 400, and 900 screw cover heads,
Series 800 explosion-proof, thermostat housings, and
panel surface mounting using two 6-32 screws
1
. The
transmitter is designed for an operating ambient
temperature of (-30 to 65)
°
C [(-22 to 149)
°
F].
Power Supply
The transmitter is designed for a nominal 24 V dc power supply. The transmitter will operate over a range of (9 to
36) V dc depending on the resistive load. Use the following formulas to determine the maximum resistive loading
(RL) allowed for the power used, or to determine minimum supply voltage (V) required for fixed resistive loads.
The formulas assume a maximum current of 20 mA.
V
MIN
= 20 mA
×
R
LOAD
+ 9 V dc R
MAXLOAD
= (V
SUPPLY
– 9 V dc ) / 20 mA
One power supply can be used for several transmitter loops. Each loop must have only one transmitter in it and all
loops must be wired in parallel. Do not forget to observe the maximum current rating for your power supply.
Note: If used in a manner not specified by the manufacture, the protection provided by the equipment may be impaired.
Wiring
The terminal block on the transmitter can accept wire from 14 to 24 gauge. Shielded or conduit encased (twisted
pair) cable is required from the transmitter to the controller, including the sensing element and lead wire. Note that
low voltage lines should be run in separate conduit isolated from high voltage or high current carrying lines.
Open Sensor Indication
When an RTD has failed due to an open sensor, the transmitter will
indicate an error. The way the error is produced is by either driving the
current low, under 4 mA (downscale burnout) or by driving the current
high, above 20 mA (upscale burnout). Upscale burnout is standard for
all Pyromation transmitters.
However, the burnout indication does not apply to a break in the lead
compensation loop. In this case, the burnout signal will drive the
transmitter either high or low depending upon which lead has broken.
RTD ELEMENT
POWER
SUPPLY
CONTROLLER
COPPER LEADS
Note 1