RB/RBS
P. 4 / 4
EM-1334 Rev.7
5-2-55, Minamitsumori, Nishinari-ku, Osaka 557-0063 JAPAN
Phone: +81(6)6659-8201 Fax: +81(6)6659-8510 E-mail: [email protected]
SIMPLE LOOP TEST OUTPUT
Option /E2
Simulated 0% and 100% output is available with Option /E2.
Switch the Loop Test Selector positions.
Top position: 0% fixed
Middle position: 100% fixed
Bottom position: Cancel the loop test mode
(Back to the normal operating mode)
CHECKING
1) Terminal wiring: Check that all cables are correctly con
-
nected according to the connection diagram.
2) Power input voltage: Check voltage across the terminal
7 – 8 with a multimeter.
3) Input: Check voltage across the terminal 3 – 4 with a
sensitive voltmeter.
(With 20°C or 68°F, approx. 220mV with Pt 100, approx.
110mV with Pt 50 Ω.)
If RTD wires are broken, the output goes over 100% (be
-
low 0% with downscale protection) due to burnout pro
-
tection function. Check leadwires in such a case.
4) Output: Check that the load resistance meets the de
-
scribed specifications.
ADJUSTMENT PROCEDURE
This unit is calibrated at the factory to meet the ordered
specifications, therefore you usually do not need any cali-
bration.
The output signal can be finely adjusted to match it to a re
-
ceiving instrument, or to compensate input wire resistance
when the unit is combined with a zenor barrier. Follow the
regular calibration procedure explained below:
■
HOW TO CALIBRATE THE OUTPUT SIGNAL
Use a signal source and measuring instruments of sufficient
accuracy level. Turn the power supply on and warm up for
more than 10 minutes.
1) ZERO: Apply 0% input and adjust output to 0%.
2) SPAN: Apply 100% input and adjust output to 100%.
3) Check ZERO adjustment again with 0% input.
4) When ZERO value is changed, repeat the above proce
-
dure 1) – 3).
MAINTENANCE
Regular calibration procedure is explained below:
■
CALIBRATION
Warm up the unit for at least 10 minutes. Apply 0%, 25%,
50%, 75% and 100% input signal. Check that the output
signal for the respective input signal remains within the
range of accuracy described in the data sheet. When the
output is out of tolerance, recalibrate the unit according to
the “ADJUSTMENT PROCEDURE” explained earlier.
LIGHTNING SURGE PROTECTION
In order to protect the unit from lightning surges entering
through signal and power supply cables, use of appropriate
lightning surge protectors are recommended. Please con-
tact M-System.
