SSD Series – Riedon™ Digital Current Sensor with RS485/MODBUS Interface by Bourns

Specifications are subject to change without notice.

Users should verify actual device performance in their specific applications.

The products described herein and this document are subject to specific legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.

Frequently Asked Questions

Q: Is it necessary to install the Model SSD on the low side

of the circuit?

A: The Model SSD Digital Current Sensor is completely

isolated, so it may be installed in either the low or high side

of the circuit.

Q: The sensor is only sending whole Coulombs and Watt-

hours, how precise are these?

A: Internally, micro-coulombs and micro-joules are counted; so

very short ADC timing intervals and very low currents are

accurately counted.

Q: What is the best way to connect to the SSD Series

terminals?

A: Make sure connections are clean and well prepared.

Bolts to be torqued to the hardware manufacturer’s

recommendations. There should be sufficient clamping

force to ensure proper connection. Overlap shown below

should be taken as a minimum. Suitable for Copper,

Copper-Clad Aluminum or Aluminum conductors.

20 mm

BUSBAR

OVERLAP

HARDWARE:

5/16-18 GRADE 5 STEEL or

M8x1.25 CLASS 8.8 STEEL

TORQUE:

11-13 ft-lb,

15-17.6 N-M

Q: What is the best way to cool the Model SSD Digital

Current Sensor?

A: A majority of the heat generated by the SSD is dissipated

through the primary conductors. Care should be taken to

ensure that the primary conductors are sized appropriately

given expected amperage and conductor length. Bourns

recommends a 115 °C maximum conductor temperature at

rated current. If there are thermal concerns, oversizing the

conductors will help minimize the operating temperature of

the Digital Current Sensor.

Q: When should I use the SSD version with the internal

120 Ω termination resistor (-T)?

A: The -T version includes a built-in 120 Ω resistor between

CANH/CANL or 485A/485B. Typical RS485 or CANbus

networks require termination at two endpoints. Use the -T

version accordingly. Avoid using more than two termination

points to ensure proper communication.

Q: What size wire is suitable for the SSD Series?

A:

Copper Conductor Ampacity Ratings (continuous)

mm2

AWG

Amps (75 °C)

mm2

AWG

Amps (75 °C)

13.3

6

65

107

0000 (4/0)

230

21.2

4

85

127

250 MCM

255

33.6

2

115

152

300 MCM

285

42.4

1

130

203

400 MCM

335

54

0 (1/0)

150

253

500 MCM

380

67

00 (2/0)

175

380

750 MCM

475

85

000 (3/0)

200

887

1500 MCM

625