www.qualitrolcorp.com
Operation
7
2.3.2. Analog
Output
An analog output is available at TB5-1(+) and TB5-2(–) that provides an analog signal
proportional to the highest temperature. The analog signal can be selected by the User
Configuration software to be 0–1 mA, 0–10 mA, 0–20 mA, 4–20 mA, or 0–5 V.
2.3.3. USB
Link
A USB data link is provided for setting up the 118 ITM. A USB plug is provided for this link.
Refer to the Setup Software section of this manual for more detailed information.
NOTE: The USB cable should only be connected when a configuration update is
required. No permanent wires should be connected to this connector.
2.3.4. RS-485 Link (Optional)
The optional RS-485 data link is accessed through a terminal block connector on the back of
the unit. This provides a method of communicating with a remote master station using Modbus
RTU protocol. Convert to a two-wire RS-485 connection jumper TB3-1 (RXD+ (B)) with TB3-3
(TXD+(B)) and jumper TB3-2 (RXD-(A)) with TB3-4 (TXD-(A)) for half duplex operation. Refer to
Appendix E of this manual for additional information.
Operation
3.1. Temperature
Display
The temperature display consists of a three-digit, seven-segment, back-lit LCD display that can
show temperatures from 0°C to 250°C, and three individual icons that identify the temperature
being displayed. The display shows each reading for approximately one second and then
automatically steps to the next reading.
The display shows the three winding temperatures and then the maximum stored temperature.
While the maximum stored temperature is displayed, both the MAX icon and the icon
representing the winding that caused the maximum reading turn ON.
3.2. Status
Lamps
Five LEDs are provided that indicate the status of the output relays. Refer to Figure 3; Front
Panel.
A yellow FAN LED indicates that the FAN relay is activated.
A red ALARM LED indicates that the ALARM relay is in the ALARM state.
A red TRIP LED indicates that the TRIP relay is in the TRIP state.
A red fourth-relay LED indicates that RELAY 4 is in the active state.
A red fifth-relay LED indicates that RELAY 5 is in the active state.
3.3. Audible
Alarm
An internal buzzer sounds each time the ALARM becomes active. The buzzer can be silenced
by pressing the SILENCE/TEST push-button. The buzzer will then turn OFF and remain OFF
until a new ALARM occurs.
