CT Clamp
A CT clamp is a device for measuring electric current and giving the direction of the flow for solar inverter, which is in fact a current sensor.
CT clamp Specification
Model | Parameters |
Current Ratio | 1000:1 |
Max Current | 100A |
Min Current | 100mA |
Rated Primary Current | 5-400Aac |
Maximum Primary Voltage | 5000Vac(insulated conductor) |
Rated Secondary Voltage | 0.333Vac |
Operating Temperature | -15℃ to +60℃ |
Operating Frequency | 50-400Hz |
Operating Humidity | <85% |
The Length Of The lead | 10m |
Accuracy | Class 1.0 maximum |
Case Material | PC/UL94-V0 |
Environmental Protection | RoHS compliance |
Phase Angle | Less than 2 degrees at 50% of rated current |
Certification | Compliance with CE requirements |

Meter overview(optional)
The meter appearance and dimensions are shown below figure as a reference.
No. | Function Pin | Remarks |
1 | Live Line Input | Input of internal current sensor |
2 | Live Line Output | output of internal current sensor |
3 | Neutral | |
4 | Neutral | |
5 | Pulse 1 out+ | |
6 | Pulse out- | |
7 | Pulse 2 out+ | |
8 | RS485 GND | |
9 | RS485 B | |
10 | RS485 A |
Pulse Output Connection
Pulse output must be fed as shown in the wiring diagram right-side.
Scrupulously respect polarities and connection mode.
Opto-coupler with potential-free SPST-NO Contact.
Contact range:5-27Vdc Max
Current input: 27mAdc
Meter Specification
Model | SDM120 Modbus Pin |
Nominal Voltage(Un) | 120V.a.c or 230 V.a.c |
Operational Voltage | 80%-120% of Un |
Basic Current (lb) | 5A |
Maximum Rated Current (Imax) | 45A |
Operational Current Range | 0.4 lb-Imax |
Over Current Withstand | 30 Imax for 0.01s |
Pulse Output | 1000imp/kWh |
International Standard | IEC62053-21/EN50470-1/3 |
Accuracy Class | Class1/Class B |
Installation Category | CAT ∥ |
Mechanical Environment | M1 |
Electromagnetic Environment | E2 |
Degree of Pollution | 2 |
Ingress Protection Degree | IP51(indoor) |
Voltage Current Accuracy | 0-5% |
Frequency Accuracy | 0-2 of mid-frequency |
Power Factor Accuracy | 1% of utility(0.01) |
Active&Apprarent Power | ±1% of range maximum |
Reactive Power Accuracy | ±1% of range maximum |
Active Energy | Class1 |
Ingress Protection Degree | Class2 |
CT clamp and meter connecting and setting are easy. If you want to know more, please click "What is a CT clamp?" and if you want to know more professionally, please download the PDF.