K-TEK AccuTrak AT100, Installation & Operation Manual

Page: 14 / 41

AT100-0200-1 Rev L (10-2010) DCN0528 14
4.12 Custom Current Ranging
4.12.1 Description and Method of Operation
All AT200 transmitters are set by the factory with the LRV set to 0 measurement and the URV set to the
range of the transmitter unless a specific calibration is indicated when the transmitter is ordered. In this standard
configuration, the transmitter will output 4mA when the float reaches the LRV and 20mA when the float reaches the
URV. Using the Level Offset (L1O) feature, the indicated measurement at this point can be changed to something
other than 0 measurement. Changing the offset will not affect the output of the transmitter. The mA output will
remain at 4.00 when the float reaches the zero mark on the sensor tube.
In some applications it may be necessary to have the transmitter output something other than 4.00mA with
the float located at the zero mark of the sensor tube. In these cases, Custom Current Ranging (CCR) can be
applied to the transmitter. CCR will allow the user to change the milliamp values associated with LRV and URV. For
example, the Lower Range Current (LRC) can be set to 5.00mA. With the LRV set to 0 measurement, the
transmitter will output 5.00mA and display 0 measurement. Once the LRC and URC are set, using the calibration
procedures in Section 4.1.1 or 4.4 will result in the current output corresponding to LRC and URC instead of 4 and
20mA. Custom Current Ranging may not be activated if the AT100 is being used in a Safety Implemented System.
4.12.2 CCR Set Up
1. Enter the Configuration Menu (CFG).
2. Scroll down to CCR.
3. Press SELECT.
4. Scroll UP or DOWN to turn CCR ON.
5. Press SELECT.
6. Exit the CFG Menu.
7. Enter the Calibration Menu (CAL).
8. Scroll down to LRC and press SELECT.
9. Using the UP and DOWN buttons enter the digits corresponding to the mA value that will be associated
with the measurement in LRV. (Press SELECT after each digit is set to move to the next digit.)
10. Scroll down to URC and press SELECT.
11. Using the UP and DOWN buttons enter the digits corresponding to the mA value that will be associated
with the measurement in URV. (Press SELECT after each digit is set to move to the next digit.)
12. Exit the CAL Menu.
To revert back to standard values for LRV and URV (4 and 20 mA respectively,) turn CCR - OFF.
4.0 TRANSMITTER CALIBRATION AND SETUP
4.11 Alarm Delay
The AT100 transmitter is designed to send the current output into a Fail Safe mode when the transmitter
does not detect a return signal from the sensor tube or the transmitter experiences a diagnostic failure. In certain
installations (such as high vibration areas) the transmitter may experience sporadic interruptions in the return signal
which are not an indication of sensor tube failure. The spiking output affect caused by the interruptions can be
eliminated by using the Alarm Delay feature. Increasing the Alarm Delay will cause the transmitter to hold the last
good level indication (and its corresponding current output) for a period of time equivalent to the Alarm Delay value
(0-99.99 seconds). If the transmitter does not detect a good return signal within this time, the output will change to
the Fail Safe selected by the jumper settings. If within the Alarm Delay time frame, a good signal is detected, the
transmitter will respond with a level indication and output based on the new reading and the Alarm Delay clock will
reset.

Setting the Alarm Delay:
- Under the CFG menu, scroll DOWN to the ALD (Alarm Delay) menu option.
- Press SELECT to access the setting.
- Use the UP and DOWN arrows to change each digit.
- Use the SELECT button to move from one digit to the next.