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Second input check 84, Heater current monitor check 84, Second analog input check 84 – Red Lion TCU User Manual

Page 92: Valve positioner check 84, Calibration 84

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Second Input Check

The Second Input Check applies to those models that have the Second

Analog Input (Remote Setpoint), Heater Current Monitor and Valve
Positioner options. Different signals are required for each option.

Heater Current Monitor Check

1. Apply signals over the range of 0 to 100 mA AC, 60 Hz to the terminals

labeled CT. The tolerance is 1% of full scale

±

1 LSD (10 to 100% of

range).

2. Calibrate the Heater Current Monitor if out of tolerance.

Second Analog Input Check

1. Apply signals over the range of 0 to 20 mA DC to the terminals labeled

Second Input, 4-20 mA+ and 4-20 mA-. The tolerance is 0.2% of full scale

±

1 LSD.

2. Calibrate the Second Analog Input if out of tolerance.

Valve Positioner Check

1. Apply signals derived from the resistor string as described in Valve

Positioner Calibration. The tolerance is 0.2% of full scale

±

1 LSD.

2. Calibrate the Second Analog Input if out of tolerance.

Calibration

When re-calibration is required (generally every two years), this procedure

should be performed by qualified technicians using appropriate equipment.
Equipment source accuracy of 0.01% or better is required.

The procedure consists of: applying accurate mV signals, setting the

thermocouple cold junction temperature, applying precision resistance and
measuring accurate mA currents, among others. Allow a 30 minute warm-up
period before starting this procedure. Do not use thermocouple wire at any
stage of calibration.

This procedure may be aborted by disconnecting power to the controller

before exiting the configuration mode. The existing calibration settings
remain in affect.
Note: After completing any of the calibration sequences, the controller defaults

the input sensor type to thermocouple type “J” (tc-j). Be sure to set input
sensor for proper type.

Configure Step 9 - Factory Service Operations (9-Fs)

Display

Parameter

Description/Comments

Code

Enter factor service
function code

48

Calibrate instrument

CAL

Millivolt Calibration

yes/no

Calibration required for both
RTD and TC input. If this
procedure is performed, the
cold junction temp and RTD
ohms calibration procedures in
turn must be completed.

CJC

Thermocouple cold
junction temperature
calibration

yes/no

Not required if only using RTD
input. This procedure can only
be performed AFTER an
accurate millivolt calibration.

rtd

RTD Resistance
Calibration

yes/no

Not required if only using TC
input. This procedure can only
be performed AFTER an
accurate mV calibration.

ANCL

Analog Output

yes/no

This parameter will not appear
if analog output option is not
installed.

2CAL

Second Analog Input
Calibration

yes/no

This parameter will not appear
if second analog input is not
installed.

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