Power Connections
It is recommended that an adequately sized circuit breaker be connected between the power service and the control to permit fail-safe removal of power before making adjustments or connections. Connect line power (white) to location N. Connect line power (black) to location L. When using an electrical “job box” mount version secure any ground (green) wire to a steel electrical box or consult local electrical codes.
The Nimbus is not compatible with Uninterruptible Power Supplies (UPS) that generate a square wave.
Fan Connections
Connect fan or fans to positions marked F (red) and L (black). Any number of fans may be controlled in parallel from one unit as long as the total current does not exceed the current rating. See table 1 and figure 9.
Temperature Sensor Selection and Connection
The Nimbus will accept signals from up to 3 temperature sensors and control fan speed based on the hottest sensor. Choose an air, surface or liquid temperature sensor from the CRI catalog or website at www.controlres.com. Each sensor, S1, S2, S3 shares a common return marked SRTN. CAUTION: SRTN is a non-isolated input; use CRI sensor P11 or other sensor with a jacketed cable if installing temperature sensors in a dwelling. When fewer than 3 sensors are used, sensors may be hooked up to S1, S2 or S3. In “Temperature mode”, if no sensors are connected or all sensors read below -25°C, fans will run at full speed and the temperature alarm will activate. The Nimbus can also be supplied with a board mount sensor, contact customer service for details. See wiring diagram, figure 9.
Remote Powered Transducer Connections
When used in the remote transducer mode, the Nimbus can power and control from any 0-5VDC transducer (humidity, pressure, flow etc.) with a maximum supply current of 5mA. Connect the + lead to SRTN, connect – to S1, connect Vout to S2.
Refer to “USING REMOTE POWERED TRANSDUCER MODE” section to set control parameters for your transducer.
Current or Voltage Control Signal Connections
When used in the current or voltage control mode (see table 2), connect a 0-10VDC or 0-20mA control signal to –ISO+ as shown in figure 9.
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Figure 9: Wiring Diagram
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on image for larger version
Over Temperature and Loss of Signal Alarm Connection (for 240Bxxxx models only)
When used in the temperature control mode, (see table 2) an over-temperature alarm can be triggered when the temperature goes 10˚C (18˚F) above the control temperature (TC) or below -25°C. When used in the Voltage or Current signal mode a “loss of signal” alarm can be triggered when DIP switch #6 is in the ON position. Alarm connections are made at –ALM+
The alarm output is a normally open, optically isolated MOS Relay. When no alarm condition is present, the relay is closed and can conduct up to 100 ma. AC or DC, of load current. When the alarm is triggered, the relay opens, and can support up to 300 Volts AC or DC across its terminals. Other alarm trigger points can be supplied, contact customer service for details. See figure 9, 9a, 9b or 9c for possible alarm configurations.
Figure 9a-d: Examples of Alternate Alarm and Control Input Configuration
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on image for larger version
| Table 11: Pin-out and Connection Options |
| Pin-outs |
Connection Options |
| Board Reference |
Description |
Terminal Block (T) |
4" (100mm) Wire (W) |
| F: TB1 (pin 1) |
Fan |
14 - 24 AWG Screw Clamp |
18 AWG Red |
| L: TB1 |
Fan |
18 AWG Black |
| L: TB1 |
Line Power |
18 AWG Black |
| N: TB1 |
Line Power |
18 AWG White |
| SRTN-: TB2 (pin 1) |
Sensor (return) |
18 AWG Brown |
| S1: TB2 |
Sensor #1 |
18 AWG Orange |
| S2: TB2 |
Sensor #2 |
18 AWG Orange |
| S3: TB2 |
Sensor #3 |
18 AWG Orange |
| -ALM: TB3 (pin 1) |
- Temp. Alarm |
18 AWG Blue |
| ALM+: TB3 |
+ Temp. Alarm |
18 AWG Yellow |
| -ISO: TB3 |
- Control Signal |
18 AWG Violet |
| ISO+: TB3 |
+ Control Signal |
18 AWG Gray |
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