The SDM-CVO4 is attached to a data logger and outputs variable voltage or current signals under data logger program control. Typical applications include driving remote current-loop display units, retransmitting measured values to industrial control systems, sending control signals to valve controllers, and providing excitation voltages or currents to external sensors.
The SDM-CVO4 includes four output channels for connecting the external devices. It outputs variable voltage or current signals under data logger program control. The outputs are isolated both from the data logger and the other channels on the SDM-CVO4, thereby avoiding ground loop problems. Each output can be set to 0 to 10 Vdc or 0 to 20 mA by the data logger program. (Current outputs can also be scaled and limited to 4 to 20 mA.)
In the current mode, the output either acts as a two-wire current controller, where the loop is powered from a remote voltage source, or generates a 0 to 20 mA current source using a voltage output derived from its own power supply.
Isolation
The SDM-CVO4 includes an internal isolation barrier and components rated to provide signal isolation for transients up to 1500 Vac (rms), 2500 Vdc nominal. The isolation is between any output and the SDM-CVO4 ground connection and between individual output channels.
Protection components are built-in, which will break down in a controlled fashion at voltages close to this limit. (See the Instruction Manual, Section 4.5 Safety Considerations, for details).
Function | Expands data logger current/voltage output capability. |
Number of Channels | 4 |
Operating Temperature | -25 to +50°C |
Operating Voltage | 12 Vdc nominal (8 to 16 V) |
Minimum Voltage Drop | 2.5 V (@ 20 mA current flow) across the internal current regulating circuit |
Maximum Input Voltage | 20 Vdc (relative to channel ground) |
EMC Status | Complies with EN55022-1:1998 and EN50082-1:1998. |
Isolation
Tested Isolation | Each channel of each unit is tested for isolation resistance at 500 Vdc. Pass level > 10 MΩ |
Current Mode
Range | 0 to 20,000 µA |
Resolution | 5 µA |
Minimum Output Current (leakage) | 5 µA (at +50°C) |
Accuracy at +23°C | ±0.02% of set current + (±5 µA) |
Typical Accuracy at -25° to +50°C | ±0.1% of set current + (±5 µA) |
Worst Case Accuracy at -25° to +50°C | ±0.15% of full scale range + (±5 µA) |
Voltage Mode
Range | 0 to 10,000 mV |
Resolution | 2.5 mV |
Maximum Output Current | 30 mA per channel |
Minimum Load Current | 5 µA if output < 200 mV |
Accuracy at +23°C | ±0.02% of set voltage + (±2.5 mV) |
Accuracy at -25° to +50°C | ±0.13% of set voltage + (±2.5 mV) |
Current Drain @ 12 Vdc
Typical Active Current | 27 or 54 mA, depending on operating mode (no load on output ports)
To estimate the total current, add the active current to the sum of all output currents multiplied by 1.5. For example, if each port is at 10 mA output, the total = 54 + (1.5•4•10) = 114 mA. |
With All Outputs Off | < 0.5 mA |