Rockwell Automation has introduced a new analog output module, the 1756-OF8H, which is part of the ControlLogix controller platform. The 1756-OF8H module features eight (8) voltage or current output channels that can be configured for 0-20 mA and 4-20 mA current output signals as well as +/-10VDC voltage output signals. The module has a resolution of 15-16 bits in all signal ranges, and the built-in digital-to-analog converter (DAC) uses R-ladder DAC, which has a monootone and code-free conversion method, and the data format is integer mode (left justified, 2’s complement), which conforms to the IEEE 32-bit floating point standard.
The 1756-OF8H module is installed in the 1756 ControlLogix chassis, occupies only one slot, and can be used as a local I/O module and remote I/O module component. The module has offset drifts of 100 µV/°C and 200 nA/°C, with a total module error of 0.15% in voltage mode and 0.3% in current mode. In addition, the gain drift of the module varies with temperature of 20 ppm/°C (voltage) and 35 ppm/°C (current), and has a total module error of 0.15% (voltage) or 0.3% (current).
The open circuit detection time of the module is only applicable to the current output configuration, and the output must be set to less than 0.1 mA. The 1756-OF8H also has calibration accuracy of 0.1% for voltage and 0.15% for current without HART function, with a standard calibration interval of about 12 months. The isolation voltage of the module is 50V, and the basic insulation between the output channel and the backplane is tested at 1500V AC for 60 seconds.
The 1756-OF8H module is suitable for a variety of industrial automation applications due to its high resolution and versatility, including but not limited to control and modulation of electrical and field equipment, transmission or retransmission of signals, and interface with measuring and recording instruments. The launch of this module further enriches Rockwell Automation’s product line in the field of industrial automation, providing customers with more choices and possibilities.