Electrical Installation; Power Supply - Honeywell Searchpoint Optima Plus Operating Instructions Manual

MAN0905_Issue 7_07/17

4.1 Power supply

The Searchpoint Optima Plus requires a voltage supply from the controller of between 18 Vdc and 32 Vdc.
The maximum power consumption is 5 W. The maximum loop resistance is 600 Ω. The minimum loop
operation is 230 Ω.
resistance for HART
®
Note: In current source mode, for supply voltages of 18 to 20 Vdc the maximum loop resistance is 500 Ω.
The table below gives the total power consumption for Searchpoint Optima Plus with some common
junction box options.
Termination unit
HALO**
XNX
DVC100 series
Honeywell Analytics Junction Box
Ensure that a minimum supply voltage of 18 Vdc is measured at the Searchpoint Optima Plus, taking into
account the voltage drop due to cable resistance.
The maximum resistance in the field cable is calculated as follows:
R loop = (V controller – V detector min) / I detector
Example:
The controller is supplying a nominal 24 Vdc (V controller), the detector minimum allowable voltage is 18
Vdc (V detector min), therefore the maximum allowable voltage drop between the controller and detector is
6Vdc; this means a voltage drop of 3 V in each core (+ve core and -ve core).
Power consumption of the detector is 5.0 W. The current required to drive the detector at the minimum
voltage is (I = P / V), 5.0 / 18 = 278 mA (I detector).
So, the maximum field cable loop resistance (R loop) = 6 / 0.278 = 22 Ω, or 11 Ω per core, (allowing for
component variations, losses, etc.).
The following tables show the maximum cable distances between the controller and Searchpoint Optima
Plus for a 1.5 mm (16 AWG*) core cable, for different termination unit options, assuming a voltage drop of
2
3 V in each core. The tables are examples only and actual cable parameters and source power supply
voltage for the application should be used to calculate the maximum cable distance allowed at the
installation site.
Termination unit
HALO**
XNX
DVC100 series
Honeywell Analytics Junction Box
*nearest equivalent
Note: Sufficient operational margins should be allowed
**Contact Honeywell Analytics for availability

4. Electrical Installation

Total power consumption including Searchpoint Optima Plus
Total power
consumption
6 W
10 W
6 W
5 W
Searchpoint Optima Plus with optional HART
6 W
10 W
6 W
5 W
Max Cable Length for 1.5 mm
(Cable resistance 12.7 Ω/km (20.4 Ω/mile))
Metres
709
433
709
866
25
output
®
Operating Instructions
2108M0550
(16 AWG*) core
2
Feet
2326
1421
2326
2841